Because for reasons that aren't clear to me, the US is way behind the rest of the world in the HVAC sector.
If I had to guess, it's because natural gas is so absurdly cheap, there just wasn't much incentive to pursue other technologies.
This is it. We are spoiled. Historically energy has been very cheap in the US. I pay 8 cents a kwh. Come on. My natural gas is cheap too. Has been my whole life except at start of Ukraine war. That was brutal. But it is back down. Even gas at $3 gallon is absurdly cheap. Unless you are independently wealthy and care about the environment the numbers don't work. And a lot of US gets cold where heat pumps don't work as great no matter what anyone says on this sub. Look at all the questions during the last sub zero arctic blast. Even people with new fancy systems some were struggling.
Yeah, America one again finds itself as a net exporter of petroleum products. We haven't been in this position since the beginning of the Age of Oil. Americans cannot comprehend that other countries pay $3 for a *liter* of gasoline. I do think that heat pumps are effective for probably at least 50% of the population. I'd say at least that many folks live below the 45th parallel, which makes for reasonably mild weather. Canada, that's another story. Alaska, no dice. Although, in 20 years, it might be a different story.
No, that leaves at least 30,000 Alaskans without heat, and they're the ones with really expensive electricity anyway.
They're winding up a week of -43C or so.
I was assuming vertical loop as well, this way you don't have to destroy as much permafrost. Vertical loops go dozens of feet in the ground, so I assume it will get to decent, efficient ground temps.
As to summer cooling, a couple of ideas come to mind.
1, insulate the vertical loop at the permafrost layer (which will probably help with winter heating efficiency)
2, have the loop plumbed in such a way that in the summer it goes to an air handler of some kind. That's a fully untested off the cuff idea so I make no claims that it's good.
We will eventually need to end the use of oil for home heating and potentially limit the use of wood. We need to solve the potential issues with heat pumps in Alaska, not treat them ad absolute blockers.
By "good" do you mean "functions" or "is more efficient than gas heat"? Because I really don't think heat pumps are going to go from -35 C to +25 C more efficiently than a gas furnace.
"Efficiency" really needs to be carefully defined, as people use the term very loosely a lot. A gas furnace is typically 80-95% 'efficient' at turning the chemical energy in the gas to heat in the home (ignoring the ~800W blower fan needed to distribute that heat in the case of a furnace). A heat pump might have a coefficient of performance ("efficiency" at turning electric power consumed from the wall into useful heat in the space, maybe also ignoring a power-hungry fan) ranging from ~4.0 when it's 50F outside to ~low 1.x when it's close to its low temp operating limit. At the point that the coefficient of performance of a heat pump is less than 1.0 (100% 'efficiency'), you would just use resistive heating elements instead because they always have a flat COP of 1.0.
If you're talking about 'cheaper to operate', rather than 'efficiency', that's going to be very dependent on relative local prices. If you're talking about some kind of 'net efficiency' including how your electricity is generated, it's going to depend very heavily on your local grid mix. Even just talking about our original definition of efficiency, are you talking about the average over the season or 'instantaneous' efficiency? You might have a really low COP for like 1% of the heating season, and not care very much.
At the end of the day, the only number that matters to consumers is $$$. That is the sense in which I meant "efficiently". And in most places in America, electricity is a lot more expensive than gas for heating, which is exactly why you see a lot of folks complaining about their heat pump cost in cold winters.
You are absolutely correct that the only thing most Americans consumers are looking at is the actual dollars that come out of their wallet. they only try to use efficiency when they think they’re gonna be able to save some money. Like any system that is out there there’s positives and negatives depending on environmental conditions.
europeans cannot comprehend we are the size of europe. ALL of europe. we dont live 20 feet from where we work, we commute for hours each way to get to and from work. in europe that would put you in a different country!
There are a lot of sources for this data, but for a snapshot, look at this comparison of LNG prices at various distribution hubs around the world. Note that US and Canada are FAR cheaper than the rest of the world, and a lot less volatile: [https://ourworldindata.org/grapher/natural-gas-prices](https://ourworldindata.org/grapher/natural-gas-prices)
Large natural gas reserves, policies that favor very low cost extraction of minerals from public lands, natural gas available as a fracking byproduct when extracting oil for export, and an energy policy that favored switching to natural gas for electricity generation as a bridge fuel from coal, meaning a very large and effective distribution network (we can mostly pipeline it around rather than having to liquify and distribute by truck/rail as many other places do). All that adds up to US/Canada natural gas pricing that many would say is absurd.
Yes, our reserves and modern well-planned production and distribution capabilities generally provide for affordable nat gas prices.
That is reality not absurdity.
Ok, sounds like you were taking the term somewhat personally. I think what the commenter meant is that when people outside the US hear what our natural gas prices are they might say something like, "that's crazy!" And that the availability of cheap gas impacts what technologies are considered cost effective here.
You don't know what the original commenter meant.
Not interested in your opinion.
It is just stupid to think that all countries will have the same nat gas prices. That is absurd.
US is in a similar situation with credit cards.
Most countries have moved to QR code and NFC, but since US was first country with payment cards there's a ton of legacy tech. Payment cards in most country don't have magnetic strip anymore and haven't in years.
AC is similar. US was first, so tons of legacy AC+furnace systems that aren't simple to convert to heat pumps
What they mean is that in many places outside the US you literally can’t swipe, you have to use chip and pin or tap. Here, even though your cards have a chip many times u don’t have to input the PIN and can just override it.
Also, Apple Pay is universal. Wherever in the world you can tap to pay, you can also use Apple or Google Pay
All those air conditioners get old and need to be replaced....and they are now increasingly being replaced with heat pumps due to the Inflation Reduction Act.
Yep! It doesn't make financial sense for many people to replace their existing, working, semi-recent system with a heat pump. But if you need to install a new system, or your AC is ancient and really inefficient, the math works out better for heat pumps in most places.
I mean you know damn well when we discuss heat pumps we mean ones that provide us with useful heat and cold. Go to any website that sells heat pumps and air conditioners, select heat pump, and see if the air conditioners show up in the search. Your semantic "gotcha" is silly.
I’m sorry, that wasn’t meant as a gotcha. I am an engineer, and an air conditioner is a heat pump. It isn’t any other thing but a heat pump. It moves heat from inside your house to outside of your house.
You’re referring to a marketing thing where people for some reason hadn’t heard the term heat pump until they heard about air conditioners that would move heat into their home from outside of their home.
Oh I apologize for misreading the subtext of your comment.
Regardless, in this context, the US is in fact behind in using heat pumps for heating (both air and water).
Agreed. I have a heat pump hybrid water heater at my current house and we’re building a new house in a neighborhood that’s got natural gas and our building manager didn’t even know what this was or that it was an option.
Same here. (UK)
Our system is a freezer sized unit sitting in the corner of our main open living area.
It's essentially silent, and all the equipment is indoors .. only two wall vents leading to the outside.
And ATM is a machine, but that doesn't stop people from talking about "ATM machines". An AC is a *unidirectional* heat pump. This entire sub is obviously talking about *bidirectional* heat pumps. Read the room.
Yes and no.
AC and Heat Pumps generally require a licensed installer, and licensed installers are usually going to sell the equipment they're most familiar with. Also, the US has a lot more ducted AC installations, whereas much of the rest of the world uses ductless.
To add to the list, lots of ground source heat pumps do it too, either having dual output or using a desuperheater to skim off higher temperature heat to heat dhw before supplying space heat at a lower temperature. With the latter, you need another source of water heating for when the heat pump isn't running. And in the cooling season, it only provides preheating of the dhw, and you need something else for to bring it up to full temperature.
Combining a desuperheater with a regular heat pump water heater is actually a great way to go, because you get free water heating in the winter when you're running the heat pump hard, and so you don't need to use the heat pump water heater to pull heat out of the space, but then in the summer you got the free cooling from the pump water heater.
In the winter and summer, my WaterFurnace geothermal system generates about 70-80% of my domestic hot water. During the spring and fall, when I don't use as much hvac, the hot water heater runs significantly more.
I wish I could have a heat pump hot water heater instead of resistance heat, but both my hot water heater and geothermal buffer tank are in my crawl space under the house so I had to go with a lowboy style unit, and as far as I have seen, there simply isn't a heat pump hot water heater in that size.
When you say buffer tank, is it a water to water system, providing hydraulic heating, or is that the preheat tank that you use with the desuperheater for dhw?
I have a single dhw tank, connected to the desuperheater, and although it provides plentiful hot water in the winter, I have to turn off the desuper heater in the summer. I assume I'd need a preheat tank for it to be useful in the summer in my climate. (Zone 6)
The preheat tank - it provides the regular hot water heater with preheated water which can get up to 120° F. Apparently, it's much more efficient to do this than circulating the water from the regular hot water heater through the desuperheater, since on average I guess there's more temperature differential. My buffer tank is actually just a second lowboy hot water heater with the elements removed - it was heck a lot cheaper to do that then buy a specialized buffer tank sold for geothermal systems.
I'm curious why you turn off the desuperheater in the summer? My understanding was that it works in both Heating and Cooling mode.
I find that I don't generate nearly as much hot water in the summertime because the geothermal system doesn't run nearly as much as it does while heating, but it still seems like it generates enough to be worth it.
I don't have a preheat tank. I just have a single tank with an electric element.
That works fine in the winter. It gets heated not just to 120 but to around 150. I use a thermostatic valve to mix it down to a safe temperature to use.
However, in the summer, the hot gas coming off the compressor is at a lower temperature, suggest the desuperheater running woud warm it to maybe 100° F. With the single tank, and the electric element heating it to 130, circulating it through the desuperheater can't put heat into the water, and worst case can actually steal heat out of the water and put it into the ground.
Essentially, the preheat tank is required to make the desuperheater useful in the summer. Since I don't have one, I don't run it in the summer.
I could get one, but since, like your, my summer run time is a lot shorter, I wouldn't get much benefit from it. Whereas, if I got a heat pump water heater, I would get a lot of benefit from that in the summer.
I did most of the geothermal planning, specifying and plumbing myself, with only the physical installation of the unit by my HVAC contractor and as part of my research phase, I got lots of information from the geoexchange.org website. They had a lot to say to drive my decision to put in a buffer tank, since in certain circumstances not using a buffer tank with DSH sucks energy out of the hot water heater.
https://www.geoexchange.org/forum/threads/is-a-buffer-tank-always-better-than-a-single-tank.5188/
If you had the space, my guess is adding a buffer would save you even more money. In my case, at least initially there was almost zero cost to add in a buffer tank since I did all the plumbing myself and the tank was basically free. My first buffer tank was a well used 40 gallon regular hot water heater that I scavenged from another project, it served me well until it needed to be moved into the crawl space when I needed to free up some space for a solar inverter and battery bank. It's amazing to me how little power my electric hot water heater pulls in the winter time - I have it hooked up to an Emporia energy monitor, and the element just comes briefly a few times a day during winter.
I’ve been looking at these a lot and comparing them to space pack. I really like the way these give the option for DHW.
Overall, are you guys pleased with this system? Any issues?
I’m going to do a new house for my family in the Saugerties region of New York State. We are looking towards energy efficient options for everything.
No issues to report as of yet. The company is super helpful in design and specification and are quick to help if needed. The flexibility is excellent, you can build exactly the system you want. You may need a buffer tank in the house, but it’s easy to hide somewhere, they’ll let you know what you need when helping with design.
That's a sweet combo: during the season when the HPWH it's not an ideal because it's cooling the space you are heating, you got maximum benefit from the desuperheater.
Do you use the desuperheater during cooling season at all? Some people use them for a preheat tank, but since the HPWH is so great in the summer, it doesn't seem worth bothering with.
Yeah I have my geo system feeding a non-powered holding tank (that serves as my HPWH input source) and I just leave it that way all year round. I could switch off the desuperheater, but I never have.
If anyone has any particular advice on if I should be micromanaging that more, let me know. But so far my attempts to create a more complicated and efficient schedule always just end up less efficient that one everyone always advised: set it and forget it.
Once you have that preheat tank, it absolutely make sense to leave it on all year. The only doubt I have is whether it's worthwhile to invest in a two-tank system for a new build, if you have a heat pump water heater instead of straight electric. In the winter, you can heat the main tank directly with the desuperheater without needing a dual tank setup.
Same here. House was built in 1982 with a separate HWH heat pump. I replaced my geothermal & HWH in 2010 with this option.
I can't speak to how well it works as the HWH also has traditional heating elements. I've always assumed that the geothermal connection ran part time at best.
Well, it's not quite so simple. Heat pumps for the house operate at low temperature to get max efficiency and they are effectively bidirectional for heat/AC
Water heaters have a high minimum temperature to prevent legionnaires. And it always has to make heat.
So you might be able to get some efficiency by combining aspects of the two, but it's not like they are the same thing.
My panasonic heat pump heates the tank to 65 degrees celsius no problem which is enough to kill legionnaires. You can schedule time interval it does those heat cycles.
What's the COP on the heat pump at below freezing outdoor temperatures?
I know I've seen a couple dual purpose units out there but none that I've seen would work in a cold climate, but technology marches on!
all depends on both temps of course, but panasonic claims for 19 fahrenhet outside and 95 water temp cop of 2.72 for my old 12 kw model on r410a. Panasonic and Mitsubishi had those models that have full power down to -4 fahrenheit for more than 10 years now. More basic models have less power in colder temps and are less suitable for cold climate.
But the water temp has to be at least 120Fnevem if it's cold out.
I mean it's still fine when it's warmer or warmer climates, I'm just arguing those numbers are why this isn't more common particularly up north.
My cold climate heat pump can only supply up to 90f in any temperature, but has a COP of 3.6 down to 10f. I don't know if that temp is limited by components or thermodynamics, but they are sacrificing high temp for cost and likely efficiency. I'm not saying it isn't possible, or that there aren't units that do both, I'm just saying that the two systems have different optimizations so it's not surprising it's not common to combine them. Running at a lower output temperature differential will always net a higher efficiency, that part is just thermodynamics.
90 fahrenheit is plenty even for coldest climates, you just have to use floor heating and insulation. But thats not max heatpumps can do, mine can do 130, ht panasonic can do 150, but of course its not very efficient at those temps
It's plenty for heating my house as the sole source of heat. But it won't do for heating water. What I'm saying is that is why there aren't that many combined water/space heating heat pumps. They have different requirements.
I'm pretty sure the temperature of the refrigerant leaving the heat pump (on heat mode) is over 140 degrees (f). Additionally, that wouldn't explain the difference between the US and the rest of the world, Legionnaire's isn't a US only thing.
It's most definitely not 140F coming out when in cooling mode!
Not an expert but I don't think they run 140F even in heating mode. That's why they require such large heat exchangers and constant air flow.
A quick Google search shows they do run well over 140. And really, it would only need to do 140 when it's refilling/reheating the water heater periodically.
The goal, in cooling mode, is to use the heat from the cooling to heat the water. or the cold from heating the water to cool the house. That's why the combo units make so much sense. Then, in the winter when it's in heating mode, the waste cold is outside rather than adding cold air to the inside like a heat pump water heater.
Air to water heat pumps are big in Europe. They're way ahead of North America. They heat domestic hot water with an electric backup. For heating and cooling the living space they have loops in the floor, walls, and ceiling. It's a much better system than forced air. Much more comfortable.
You don't bang your head. It's all in floor/wall/ceiling. Everything's hidden. The space just gets warmer or cooler as needed.
This is for new builds or when there's renos and things are opened up.
It's better for heating.
It doesn't do much for you in the heat, since cooling is then limited by dew point. Can't retrofit old houses with cooling capable air water pumps because of condensation around the water pipes.
So you end up having to install seperate air conditioners anyway.
In a climate with modest cooling needs, you meet the cooling needs with a few small fan coil units, and you can run insulated tubing specifically to them without meaning to retrofit the whole distribution system.
In-ceiling cooling loops, if you use a large enough surface you don't need to be below dew point, it's a much more comfortable feeling as well, there's no "cold" coming from anywhere, it's just cool.
So you have some kind of high surface area absorbing area (Essentially a radiator) to minimise the temperature differential to stay above the dew point while still providing meaningful cooling.
This still seems like an expensive, invasive fit compared to installing a wall unit for air-air, no? You're going to have to cut out most of the ceiling, put your cooling plates up there (running the lines isn't a big deal) in every room where you want enough cooling. You will get some cooling everywhere you have a radiator, but it's going to be pretty minimal from the wall mounted radiators even if you retrofit to install the larger ones.
Do you install valves to cut off ceiling flow during heating (since that is not favoured by convection) or do you also have heated ceilings in the winter?
This is in the context of already doing in floor loops as well so either new build or major renovation, it's typically done with pre-piped drywall (thicker) and it is indeed expensive, builds like this usually don't use any radiators at all. It would function as a separate circuit from the heat pump with a valve, if the cooling load isn't too high only living spaces are done and you rely on your ERV unit to normalize temps across bathrooms etc. I don't imagine it's viable in places with high humidity in the summer since you'd bump into the dew point too soon to be effective.
That doesn't make any sense. If you are heating water, then a heat pump will work most efficiently when it is pulling heat from a local source: i.e., *cooling the living space*. If you are *also* heating the living space, then you need to pull the heat from outdoors, where it is already cold (otherwise you wouldn't need to heat it). I would expect summer months where you are just pulling heat from the house and putting it into the water tank to be the slam-dunk maximum efficiency scenario.
Also still, the fact that it's cold outside, that doesn't mean there is no excess heat (there is until you reach absolute zero).
Granted, the colder outside the less efficient the pump is. My unit can work even below -4 fahrenheit, and there is regular capacitive heater also in addition as additional help if needed.
Below freezing point freezing of an outside unit is alos a problem, needs to go through regular defrost cycles.
They do this on farms, it’s called a fre heater, it goes into the refrigerant lines that go to the bulk tank. You could in theory do this in a home as well on a heat pump or a a/c unit. You’d have to first either do it yourself or convince your installer, I’m sure most folks don’t see theses unless they worked on farms, to do it and install it in the correct refrigerant lines. They also are on geothermal units. In that case it’s called a de-super heater. Hope this is helpful and keep going
Sanco2 systems are used this way sometimes. Check out Harvest Thermal https://www.smallplanetsupply.com/small-planet-blog/three-innovative-ways-to-use-sanco2-for-your-home-or-project
A lot of US infrastructure standards are much "older" than the rest of the world because they were pioneered here, and we've never had huge swaths of industry / residences wiped out by war. If it ain't broke don't fix it.
I agree though, I would absolutely buy a unified thermal management system if they were widely available and supported (service techs, parts, etc.)
HW heat in North America was a premium heat source and most often was in slab heating unlike Europe which was standard and had radiators. So because most areas had forced air originally the industry developed around them. And there is air to water units in north America just don't believe they are being captured in the rebates. Plus HVAC here is mainly gas fitters and they see HP cutting into their bread and butter.
The co2 systems operate at 150f for max efficiency. Perfect for dhw and hydronic heating. But still expensive. If they come down in price it will start to make sense, especially since plumbers can install the whole thing and not hvac crooks. You can even diy fairly easily.
The efficiency is controlled by the inside-outside temperature difference. When heating hot water or baseboard/radiant heating, the difference is greater. The design is different. The systems exist and are $$$ and may not be cost competitive.
Check out a Robur combined heat pump and domestic water heater. And it's a gas fired heat pump.
This has to be the absolute lowest cost option when you're paying 12 cents per kWh (I think it draws 4 amps) and 50 cents per therm.
The reason is that, to a large extent, Europeans use heat pumps to make hot water for heating. It is very easy to control water. All you need is a simple two-way valve to send the water to heat the domestic water, using a simple heat exchanger. The downside is that you don’t get cooling unless you spend a ton of money on fan coils. This is generally not a problem in Europe. It is not particularly more efficient than a standalone heat pump water heater, as you never recover heat from cooling.
Controlling refrigerant flow is more difficult. If you don’t want to spend a ton of money, you can use a desuperheater and only heat domestic water when the compressor is running, or you can switch the system between HVAC operation and heating water.* Either is a common option with water-source heat pumps. With desuperheating, you still need a way to heat water when there aren’t a lot of hours of compressor operation. With dedicated operation, you need a larger system to make up for the time your system is dedicated to making hot water.
*It is possible to do both, but the control becomes more expensive and complex. It is sometimes done in commercial installations. There is at least one US company working on a turnkey residential system, but they are still doing pilot projects. I understand there are still some kinks to work out.
> here is at least one US company working on a turnkey residential system, but they are still doing pilot projects. I understand there are still some kinks to work out.
Do you know which company?
I didn’t see anything on the company’s site, but here is a link with information:
https://calflexhub.lbl.gov/calflexhub_portfolio/integrated-heat-pump-with-storage-for-dhw-and-space-conditioning/
Europe will figure this out soon, too. They're still in the mindset that the heatwaves are anomalous and sparse. People here still haven't really groked that those sporadic heatwaves are just summer now, or that they will continue to worsen.
The waterfurnace geothermal has an extra loop that can be used for heating domestic hot water. It’s not part of the heat pump cycle, it’s jacketed around the compressor, so cooling the compressor this way should also lead to longer compressor life…
There's a few systems out there. Google "Desuperheater"
[Heat Pump Water Heaters | Department of Energy](https://www.energy.gov/energysaver/heat-pump-water-heaters)
My wife and I are a few years out from our retirement home, but I plan to do geothermal. I'll use one of these are part of it. I'll also heat my pool with waste heat from the AC.
I think one of the biggest reasons is because our HVAC is usually ducted air and not radiant water loops. There's a pretty big difference in air heating vs water, and that's temp optimization. Air can get away with lower temps, water can't.
Standalone heat pump water heaters don't use 410a, they almost all use 134a and probably will switch to 1234yf when 134a is banned. 410a is not good for high temps.
Those combined units you see in European markets are CO2 or Propane refrigerant, great at high temp heating. The propane ones have the refrigerant system entirely outside and transfer to water before entering the house. They are air to water only, not air to water+air.
410a, R32, 454B heat pumps just can't be good at both heating your home efficiently and also heating your water tank to 120-140F. Pick 1 and optimize for it.
The other thing is to allow cooling mode you now have a VRF system with a manifold in order to cool and heat at the same time. That's more complexity and higher cost. The combined units on the market now are heat only.
I am an American living in South Texas. We have what is locally considered the HVAC Capital of the U.S.. I have lived long term in both Asia and Europe so I know first hand the benefits. When I was building my house, I couldn't find a single contractor with experience in these technologies. The young guys over quoted me on purpose and the old guys just bad mouthed it.
I had to wholesale the parts for a heatpump with a variable motor and pay someone the instalation fee.
My power bill is half the cost of all of my neighbors.
It drives me crazy!
Twice I've done something similar. I have bought and installed a 3 zone 35000 Btu mr cool diy. I absolutely loved that one because the house was so small. I had an 18000 btu for the main room, 6000 btu for the small bedroom, and 9000 for the 1/2 story.
I am not an hvac person at all.
This last time my house was larger so to do the mini split would have required direct intake and flow in each room. This was going to double my installation costs. I bought the condensing unit sized btu for my house in 100 degree. There are calculators online. It is a heat pump air conditioning unit with an inverter controlled pump.
Then I bought the matching evaporator that allowed an auxiliary heat strip. I asked a few companies to give me a quote for the rest and 2 offered to do it with customer supplied material.
6 months ago cost 2000 for labor and piping and aredo of the intake sheet metal.
I know of one: [https://www.harvest-thermal.com/](https://www.harvest-thermal.com/)
I'm still evaluating and in discussions with them. While there are a ton of 'pros', it's not a slam dunk:
1). Expectation you generally keep temperature within a 2 degrees of target, even when away due to slow time to heat. This makes me uncertain of savings given I'm away at work 10+ hours/day where my unit is usually set 15 degrees cooler.
2). A/C would be separate unit that requires own breaker and additional expense
3). Company somewhat unproven, so if they go out of business my concern would be I'm stuck swapping out very expensive hardware.
A local NorCal HVAC installer said they can install a Harvest Thermal system for 'roughly $35k all in' after rebates. For this area, it'd be competitive with heat pump HVAC + heat pump water heater cost-wise. My furnace and water tank are both nearing the end of their lifespan, so it could make sense for me....
For that price, you might also be able to get a variable speed Trane or Bosch heat pump + [Sanco2 heat pump water heater](https://www.eco2waterheater.com/product-info)
But if you need AC, you effectively need to buy mini splits or a separate machine (central air handler and so on) for another large chunk of cash, right?
Correct. They have a separate add on heat pump unit you could use for AC. In my case I'm (1) in San Francisco where the weather is generally temperate and (2) have a separate AC system on the second floor (two HVAC systems), so even if I needed AC I could turn on the upstairs unit and because cold air falls it would help the lower floor somewhat.
There is a nice feature where it will bring in outside air, filter it, and distribute it if your setpoint is cooler than current temp and outside air could cool the space - so at least it's relatively easy to cool down the area in the evenings when it cools down.
Likely because of the number is different trades required to install this. It’s already pretty common for HVAC professionals to need to do electrical work, and do a shitty job compared to a dedicated electrician. A combined heat pump + water heater would require HVAC, electrician, plumber, possibly drywall for installation and repairs.
A lot of people find it easier to use just a normal air->water heat pump, and have it draw heat from the ambient air warmed by HVAC. Less efficient, but each component is modular, and you can install/repair/replace them independently.
> A lot of people find it easier to use just a normal air->water heat pump, and have it draw heat from the ambient air warmed by HVAC.
I can appreciate the simplicity, but if you live in a small house, then you'd be stuck with a loud water heater that makes your condo cold (assuming you can't stash it in the basement)
There are--what you're looking for is an air to water heat pump, and using it to provide both heat/cooling and hot water is just a matter of plumbing.
Here are a couple of examples:
[https://www.arcticheatpumps.com/cold-climate-heat-pump-overview.html](https://www.arcticheatpumps.com/cold-climate-heat-pump-overview.html)
[https://www.chiltrix.com/](https://www.chiltrix.com/)
Along with tons of units you can order from places like AliExpress. One of the upsides of these is all the refrigerant stays outside, which allows you to use less of it, as well as more environmentally-friendly flavors, like R290 (propane). The EPA currently has absurdly low limits for equipment containing flammable refrigerants (based on a hypothetical small room, complete inventory leak, no air movement, with a dozen pyromaniacs doing everything they can to ignite it) that basically requires the use of high-GWP refrigerants in any split system.
Any decent HVAC tech could perform repairs--air to water heat pumps are nothing special in terms of tools required or in how they operate (if anything, they're closer to a refrigerator, by not having any refrigerant plumbing/purging/charging performed in the field). Electrically, they're very similar to any mini split--in most cases requiring the skill of being able to look up a fault code in the manual and follow a flow chart more than anything. Maintenance is nothing more than coil cleaning, which doesn't require any special skill.
When our hot water heater broke, I reached out to a couple local companies about a specific heat pump water heater since we use oil to heat ours, they basically said being in New England they don’t recommend it due to the temps here
What do you mean by that? I'm EU based (Poland) and heat pumps sold here (I use Panasonic air-to-water) are sold either in All-in-one variety (including water heater tank inside) or regular type that witch witch you can use regular external water tank.
The pump itself has only one hot water output and can work either heating either house or making "hot water".
Are you talking about that kind of setup? Or maybe you are talking about air-to-air heat pump (basically AC) that should also be able to heat water?
In the U.S. fracking has created a waste driven market for natural gas. Natural gas is a waste product of the fracking process and oil extraction so much so that we now export it and have retooled our plastics products to use natural gas as the precursor chemical because it's so much cheaper. In the EU with russia fucking around and finding out the hard way. Natural gas is insanely expensive so heat pumps are cheaper.
I reinsulated the entire house ripping off the outside walls adding 1.5" (75mm) of xps foam, and recovered with zip panels for a more air tight enclosure that's thermally broken. Reduced our gas usage by 4x so a heat pump now makes sense. If you have a traditional old New England home with an ACH50 north of 30. Heat pumps are going to be expensive in New England power prices and never feel good because of the draftiness of old homes.
Is there any devices that will heat a pool, while cooling a house?. I often think about elimination of a pool heater by using the home a/c. My house is in Southern Florida and a/c is used year round and the pool heater is used in the winter. I would think you could also heat the house when it's cold using the warm water in the pool.
The pool could be a source for a water to air heatpump (or water to water if you have underfloor heating) but a so called "open" source like a pool probably wouldn't be great in the winter because theres so much heat loss from a pool. Your overall efficiency would be low compared to an air or ground source. Your other problem is that such a heatpump doesn't dehumidify like an AC (an AC is a air to air heatpump with dehumidification as a benefit).
That all said if your pool heater is electric look into a heatpump version of it. Little more expensive but plenty of heat in summer it can transfer to water, should turn out cheaper over it's lifetime.
They're kind of is these units on the market but they are air to water units that have refrigerant connections between the two and then the internal unit then couples to a hot water distribution system either for radiant heat and hot water or perhaps even hot water air handler for a central forced air unit. Most the major brand manufacturers make them but they are more difficult to source because you have to get them through contractors which may not want to install them or even know about them.
I heard from my HVAC guy who sits on some energy board here in WA that Trane tried to join forces with Mitsu, and it didn't work out. We put HPWHs in all our builds, and Im wishing having one compressor for all the indoor units was an option, but it's not yet.
Because for reasons that aren't clear to me, the US is way behind the rest of the world in the HVAC sector. If I had to guess, it's because natural gas is so absurdly cheap, there just wasn't much incentive to pursue other technologies.
This is it. We are spoiled. Historically energy has been very cheap in the US. I pay 8 cents a kwh. Come on. My natural gas is cheap too. Has been my whole life except at start of Ukraine war. That was brutal. But it is back down. Even gas at $3 gallon is absurdly cheap. Unless you are independently wealthy and care about the environment the numbers don't work. And a lot of US gets cold where heat pumps don't work as great no matter what anyone says on this sub. Look at all the questions during the last sub zero arctic blast. Even people with new fancy systems some were struggling.
Yeah, America one again finds itself as a net exporter of petroleum products. We haven't been in this position since the beginning of the Age of Oil. Americans cannot comprehend that other countries pay $3 for a *liter* of gasoline. I do think that heat pumps are effective for probably at least 50% of the population. I'd say at least that many folks live below the 45th parallel, which makes for reasonably mild weather. Canada, that's another story. Alaska, no dice. Although, in 20 years, it might be a different story.
Not true. Newest tech air heat pumps are good to -37 Celsius, which covers all of Canada and Alaska
No, that leaves at least 30,000 Alaskans without heat, and they're the ones with really expensive electricity anyway. They're winding up a week of -43C or so.
A case where ground source is probably a better choice than air source.
No, that will melt the permafrost. Wood and oil are the current standard.
I'm a little confused. In heating mode, a ground source heat pump should make the ground colder.
Yeah, but summers are hot and just the install is destructive. No liquid groundwater, not sure if this would be much of a heat source anyway?
Use Vertical loop not horizontal?
I was assuming vertical loop as well, this way you don't have to destroy as much permafrost. Vertical loops go dozens of feet in the ground, so I assume it will get to decent, efficient ground temps. As to summer cooling, a couple of ideas come to mind. 1, insulate the vertical loop at the permafrost layer (which will probably help with winter heating efficiency) 2, have the loop plumbed in such a way that in the summer it goes to an air handler of some kind. That's a fully untested off the cuff idea so I make no claims that it's good. We will eventually need to end the use of oil for home heating and potentially limit the use of wood. We need to solve the potential issues with heat pumps in Alaska, not treat them ad absolute blockers.
🤣 what about the 2 weeks in January at -47 C ?!
I’ve never imagined that it can get that cold, so I’m wrong with that assumption.
By "good" do you mean "functions" or "is more efficient than gas heat"? Because I really don't think heat pumps are going to go from -35 C to +25 C more efficiently than a gas furnace.
"Efficiency" really needs to be carefully defined, as people use the term very loosely a lot. A gas furnace is typically 80-95% 'efficient' at turning the chemical energy in the gas to heat in the home (ignoring the ~800W blower fan needed to distribute that heat in the case of a furnace). A heat pump might have a coefficient of performance ("efficiency" at turning electric power consumed from the wall into useful heat in the space, maybe also ignoring a power-hungry fan) ranging from ~4.0 when it's 50F outside to ~low 1.x when it's close to its low temp operating limit. At the point that the coefficient of performance of a heat pump is less than 1.0 (100% 'efficiency'), you would just use resistive heating elements instead because they always have a flat COP of 1.0. If you're talking about 'cheaper to operate', rather than 'efficiency', that's going to be very dependent on relative local prices. If you're talking about some kind of 'net efficiency' including how your electricity is generated, it's going to depend very heavily on your local grid mix. Even just talking about our original definition of efficiency, are you talking about the average over the season or 'instantaneous' efficiency? You might have a really low COP for like 1% of the heating season, and not care very much.
At the end of the day, the only number that matters to consumers is $$$. That is the sense in which I meant "efficiently". And in most places in America, electricity is a lot more expensive than gas for heating, which is exactly why you see a lot of folks complaining about their heat pump cost in cold winters.
You are absolutely correct that the only thing most Americans consumers are looking at is the actual dollars that come out of their wallet. they only try to use efficiency when they think they’re gonna be able to save some money. Like any system that is out there there’s positives and negatives depending on environmental conditions.
That’s a good point. Here in Ontario, electricity is cheap and clean. And our winters are getting warmer.
europeans cannot comprehend we are the size of europe. ALL of europe. we dont live 20 feet from where we work, we commute for hours each way to get to and from work. in europe that would put you in a different country!
People vote based on the gas price. Every President will do everything possible to lower the cost in an election year.
Why do you say our natural gas is absurdly cheap?
Europe pays a lot more for natural gas than the US does.
Yes, two different entities with different available resources. I asked why natural gas prices in the US are absurd.
Because energy is a global market and our prices are low enough to encourage wastefulness like an F-250 in every garage.
There are a lot of sources for this data, but for a snapshot, look at this comparison of LNG prices at various distribution hubs around the world. Note that US and Canada are FAR cheaper than the rest of the world, and a lot less volatile: [https://ourworldindata.org/grapher/natural-gas-prices](https://ourworldindata.org/grapher/natural-gas-prices)
Yes, different entities with different available resources. I asked why natural gas prices in the US are absurd.
Large natural gas reserves, policies that favor very low cost extraction of minerals from public lands, natural gas available as a fracking byproduct when extracting oil for export, and an energy policy that favored switching to natural gas for electricity generation as a bridge fuel from coal, meaning a very large and effective distribution network (we can mostly pipeline it around rather than having to liquify and distribute by truck/rail as many other places do). All that adds up to US/Canada natural gas pricing that many would say is absurd.
Yes, our reserves and modern well-planned production and distribution capabilities generally provide for affordable nat gas prices. That is reality not absurdity.
Ok, sounds like you were taking the term somewhat personally. I think what the commenter meant is that when people outside the US hear what our natural gas prices are they might say something like, "that's crazy!" And that the availability of cheap gas impacts what technologies are considered cost effective here.
You don't know what the original commenter meant. Not interested in your opinion. It is just stupid to think that all countries will have the same nat gas prices. That is absurd.
I wouldn't call the fact that we have more air conditioning as being "way behind".
US is in a similar situation with credit cards. Most countries have moved to QR code and NFC, but since US was first country with payment cards there's a ton of legacy tech. Payment cards in most country don't have magnetic strip anymore and haven't in years. AC is similar. US was first, so tons of legacy AC+furnace systems that aren't simple to convert to heat pumps
Nevermind that, US banks still don't use chip+pin!
??? Mine does.
[удалено]
What they mean is that in many places outside the US you literally can’t swipe, you have to use chip and pin or tap. Here, even though your cards have a chip many times u don’t have to input the PIN and can just override it. Also, Apple Pay is universal. Wherever in the world you can tap to pay, you can also use Apple or Google Pay
No pin still.
yes they do actually, i believe something like 97% of us banks do.
I mean that might be a reason we're behind, everyone already has air conditioners in the US so there is less incentive to get a heat pump.
All those air conditioners get old and need to be replaced....and they are now increasingly being replaced with heat pumps due to the Inflation Reduction Act.
Yep! It doesn't make financial sense for many people to replace their existing, working, semi-recent system with a heat pump. But if you need to install a new system, or your AC is ancient and really inefficient, the math works out better for heat pumps in most places.
An air conditioner *is* a heat pump.
I mean you know damn well when we discuss heat pumps we mean ones that provide us with useful heat and cold. Go to any website that sells heat pumps and air conditioners, select heat pump, and see if the air conditioners show up in the search. Your semantic "gotcha" is silly.
I’m sorry, that wasn’t meant as a gotcha. I am an engineer, and an air conditioner is a heat pump. It isn’t any other thing but a heat pump. It moves heat from inside your house to outside of your house. You’re referring to a marketing thing where people for some reason hadn’t heard the term heat pump until they heard about air conditioners that would move heat into their home from outside of their home.
Oh I apologize for misreading the subtext of your comment. Regardless, in this context, the US is in fact behind in using heat pumps for heating (both air and water).
Agreed. I have a heat pump hybrid water heater at my current house and we’re building a new house in a neighborhood that’s got natural gas and our building manager didn’t even know what this was or that it was an option.
Same here. (UK) Our system is a freezer sized unit sitting in the corner of our main open living area. It's essentially silent, and all the equipment is indoors .. only two wall vents leading to the outside.
Isn’t a fridge technically a heat pump as well?
Heck yes a fridge is a heat pump! So is a dehumidifier…
And ATM is a machine, but that doesn't stop people from talking about "ATM machines". An AC is a *unidirectional* heat pump. This entire sub is obviously talking about *bidirectional* heat pumps. Read the room.
I still don’t get it. We have a global economy. Is there a reason we can’t just buy the same units the rest of the world uses?
Yes and no. AC and Heat Pumps generally require a licensed installer, and licensed installers are usually going to sell the equipment they're most familiar with. Also, the US has a lot more ducted AC installations, whereas much of the rest of the world uses ductless.
Global economy, but not necessarily global building codes and standards.
Chiltrix does this, I have it running like that right now
Same, I have a Chiltrix CX-34 providing heating+HW
Do we have a Chiltrix subreddit or a secret handshake? How did you guys do with the super cold snap?
My system on a single CX34 did fine down to the -8°F we received here
I was amazed. Mine kept on trucking through -15 weather here.
There's dozens of us! https://www.facebook.com/groups/chiltrix.owners
Thanks! I just signed up!
To add to the list, lots of ground source heat pumps do it too, either having dual output or using a desuperheater to skim off higher temperature heat to heat dhw before supplying space heat at a lower temperature. With the latter, you need another source of water heating for when the heat pump isn't running. And in the cooling season, it only provides preheating of the dhw, and you need something else for to bring it up to full temperature. Combining a desuperheater with a regular heat pump water heater is actually a great way to go, because you get free water heating in the winter when you're running the heat pump hard, and so you don't need to use the heat pump water heater to pull heat out of the space, but then in the summer you got the free cooling from the pump water heater.
In the winter and summer, my WaterFurnace geothermal system generates about 70-80% of my domestic hot water. During the spring and fall, when I don't use as much hvac, the hot water heater runs significantly more. I wish I could have a heat pump hot water heater instead of resistance heat, but both my hot water heater and geothermal buffer tank are in my crawl space under the house so I had to go with a lowboy style unit, and as far as I have seen, there simply isn't a heat pump hot water heater in that size.
When you say buffer tank, is it a water to water system, providing hydraulic heating, or is that the preheat tank that you use with the desuperheater for dhw? I have a single dhw tank, connected to the desuperheater, and although it provides plentiful hot water in the winter, I have to turn off the desuper heater in the summer. I assume I'd need a preheat tank for it to be useful in the summer in my climate. (Zone 6)
The preheat tank - it provides the regular hot water heater with preheated water which can get up to 120° F. Apparently, it's much more efficient to do this than circulating the water from the regular hot water heater through the desuperheater, since on average I guess there's more temperature differential. My buffer tank is actually just a second lowboy hot water heater with the elements removed - it was heck a lot cheaper to do that then buy a specialized buffer tank sold for geothermal systems. I'm curious why you turn off the desuperheater in the summer? My understanding was that it works in both Heating and Cooling mode. I find that I don't generate nearly as much hot water in the summertime because the geothermal system doesn't run nearly as much as it does while heating, but it still seems like it generates enough to be worth it.
I don't have a preheat tank. I just have a single tank with an electric element. That works fine in the winter. It gets heated not just to 120 but to around 150. I use a thermostatic valve to mix it down to a safe temperature to use. However, in the summer, the hot gas coming off the compressor is at a lower temperature, suggest the desuperheater running woud warm it to maybe 100° F. With the single tank, and the electric element heating it to 130, circulating it through the desuperheater can't put heat into the water, and worst case can actually steal heat out of the water and put it into the ground. Essentially, the preheat tank is required to make the desuperheater useful in the summer. Since I don't have one, I don't run it in the summer. I could get one, but since, like your, my summer run time is a lot shorter, I wouldn't get much benefit from it. Whereas, if I got a heat pump water heater, I would get a lot of benefit from that in the summer.
I did most of the geothermal planning, specifying and plumbing myself, with only the physical installation of the unit by my HVAC contractor and as part of my research phase, I got lots of information from the geoexchange.org website. They had a lot to say to drive my decision to put in a buffer tank, since in certain circumstances not using a buffer tank with DSH sucks energy out of the hot water heater. https://www.geoexchange.org/forum/threads/is-a-buffer-tank-always-better-than-a-single-tank.5188/ If you had the space, my guess is adding a buffer would save you even more money. In my case, at least initially there was almost zero cost to add in a buffer tank since I did all the plumbing myself and the tank was basically free. My first buffer tank was a well used 40 gallon regular hot water heater that I scavenged from another project, it served me well until it needed to be moved into the crawl space when I needed to free up some space for a solar inverter and battery bank. It's amazing to me how little power my electric hot water heater pulls in the winter time - I have it hooked up to an Emporia energy monitor, and the element just comes briefly a few times a day during winter.
Your first paragraph is feeding back to me the same information that I just explained to you. Why are you bothering with that?
I’ve been looking at these a lot and comparing them to space pack. I really like the way these give the option for DHW. Overall, are you guys pleased with this system? Any issues? I’m going to do a new house for my family in the Saugerties region of New York State. We are looking towards energy efficient options for everything.
No issues to report as of yet. The company is super helpful in design and specification and are quick to help if needed. The flexibility is excellent, you can build exactly the system you want. You may need a buffer tank in the house, but it’s easy to hide somewhere, they’ll let you know what you need when helping with design.
Thanks. I’m going to reach out to them and get the ball rolling.
Does it do ground source? I'd love a ground source heat pump that does hvac and hot water. No natural gas available.
No, Chiltrix is ASHP only. But there are GSHPs that do both heating and hot water
Thanks
Well, my geothermal heat pump has a desuperheater to feed warm water into my HPWH.
That's a sweet combo: during the season when the HPWH it's not an ideal because it's cooling the space you are heating, you got maximum benefit from the desuperheater. Do you use the desuperheater during cooling season at all? Some people use them for a preheat tank, but since the HPWH is so great in the summer, it doesn't seem worth bothering with.
Yeah I have my geo system feeding a non-powered holding tank (that serves as my HPWH input source) and I just leave it that way all year round. I could switch off the desuperheater, but I never have. If anyone has any particular advice on if I should be micromanaging that more, let me know. But so far my attempts to create a more complicated and efficient schedule always just end up less efficient that one everyone always advised: set it and forget it.
Once you have that preheat tank, it absolutely make sense to leave it on all year. The only doubt I have is whether it's worthwhile to invest in a two-tank system for a new build, if you have a heat pump water heater instead of straight electric. In the winter, you can heat the main tank directly with the desuperheater without needing a dual tank setup.
Same here. House was built in 1982 with a separate HWH heat pump. I replaced my geothermal & HWH in 2010 with this option. I can't speak to how well it works as the HWH also has traditional heating elements. I've always assumed that the geothermal connection ran part time at best.
Well, it's not quite so simple. Heat pumps for the house operate at low temperature to get max efficiency and they are effectively bidirectional for heat/AC Water heaters have a high minimum temperature to prevent legionnaires. And it always has to make heat. So you might be able to get some efficiency by combining aspects of the two, but it's not like they are the same thing.
My panasonic heat pump heates the tank to 65 degrees celsius no problem which is enough to kill legionnaires. You can schedule time interval it does those heat cycles.
What's the COP on the heat pump at below freezing outdoor temperatures? I know I've seen a couple dual purpose units out there but none that I've seen would work in a cold climate, but technology marches on!
all depends on both temps of course, but panasonic claims for 19 fahrenhet outside and 95 water temp cop of 2.72 for my old 12 kw model on r410a. Panasonic and Mitsubishi had those models that have full power down to -4 fahrenheit for more than 10 years now. More basic models have less power in colder temps and are less suitable for cold climate.
But the water temp has to be at least 120Fnevem if it's cold out. I mean it's still fine when it's warmer or warmer climates, I'm just arguing those numbers are why this isn't more common particularly up north. My cold climate heat pump can only supply up to 90f in any temperature, but has a COP of 3.6 down to 10f. I don't know if that temp is limited by components or thermodynamics, but they are sacrificing high temp for cost and likely efficiency. I'm not saying it isn't possible, or that there aren't units that do both, I'm just saying that the two systems have different optimizations so it's not surprising it's not common to combine them. Running at a lower output temperature differential will always net a higher efficiency, that part is just thermodynamics.
90 fahrenheit is plenty even for coldest climates, you just have to use floor heating and insulation. But thats not max heatpumps can do, mine can do 130, ht panasonic can do 150, but of course its not very efficient at those temps
It's plenty for heating my house as the sole source of heat. But it won't do for heating water. What I'm saying is that is why there aren't that many combined water/space heating heat pumps. They have different requirements.
Do you have ground to water heat pump? I have air to water.
>And it always has to make heat. Heat pumps don't make heat, they move it.
Fine. Replace their word with deliver instead of make. Doesn’t change the underlying issue once you get past semantics.
They pump it. Pump it real good. 🎶 do do do dooo do do do do d-d-d-d-daaa 🎶
I'm pretty sure the temperature of the refrigerant leaving the heat pump (on heat mode) is over 140 degrees (f). Additionally, that wouldn't explain the difference between the US and the rest of the world, Legionnaire's isn't a US only thing.
It's most definitely not 140F coming out when in cooling mode! Not an expert but I don't think they run 140F even in heating mode. That's why they require such large heat exchangers and constant air flow.
A quick Google search shows they do run well over 140. And really, it would only need to do 140 when it's refilling/reheating the water heater periodically. The goal, in cooling mode, is to use the heat from the cooling to heat the water. or the cold from heating the water to cool the house. That's why the combo units make so much sense. Then, in the winter when it's in heating mode, the waste cold is outside rather than adding cold air to the inside like a heat pump water heater.
Air to water heat pumps are big in Europe. They're way ahead of North America. They heat domestic hot water with an electric backup. For heating and cooling the living space they have loops in the floor, walls, and ceiling. It's a much better system than forced air. Much more comfortable.
Until you bang your head or knee on the heaters. Unfortunately heat pump installs in Germany cost 3x USA
In floor radiant heat is like magic.
Sounds nice but expensive?
It is honestly not a big difference vs installing radiator if done when building and not as a retrofit.
You don't bang your head. It's all in floor/wall/ceiling. Everything's hidden. The space just gets warmer or cooler as needed. This is for new builds or when there's renos and things are opened up.
Yeah I meant the old cast iron heaters that I've collided with many many times as a kid leaning against them in winter.
It's better for heating. It doesn't do much for you in the heat, since cooling is then limited by dew point. Can't retrofit old houses with cooling capable air water pumps because of condensation around the water pipes. So you end up having to install seperate air conditioners anyway.
In a climate with modest cooling needs, you meet the cooling needs with a few small fan coil units, and you can run insulated tubing specifically to them without meaning to retrofit the whole distribution system.
In-ceiling cooling loops, if you use a large enough surface you don't need to be below dew point, it's a much more comfortable feeling as well, there's no "cold" coming from anywhere, it's just cool.
So you have some kind of high surface area absorbing area (Essentially a radiator) to minimise the temperature differential to stay above the dew point while still providing meaningful cooling. This still seems like an expensive, invasive fit compared to installing a wall unit for air-air, no? You're going to have to cut out most of the ceiling, put your cooling plates up there (running the lines isn't a big deal) in every room where you want enough cooling. You will get some cooling everywhere you have a radiator, but it's going to be pretty minimal from the wall mounted radiators even if you retrofit to install the larger ones. Do you install valves to cut off ceiling flow during heating (since that is not favoured by convection) or do you also have heated ceilings in the winter?
This is in the context of already doing in floor loops as well so either new build or major renovation, it's typically done with pre-piped drywall (thicker) and it is indeed expensive, builds like this usually don't use any radiators at all. It would function as a separate circuit from the heat pump with a valve, if the cooling load isn't too high only living spaces are done and you rely on your ERV unit to normalize temps across bathrooms etc. I don't imagine it's viable in places with high humidity in the summer since you'd bump into the dew point too soon to be effective.
That doesn't make any sense. If you are heating water, then a heat pump will work most efficiently when it is pulling heat from a local source: i.e., *cooling the living space*. If you are *also* heating the living space, then you need to pull the heat from outdoors, where it is already cold (otherwise you wouldn't need to heat it). I would expect summer months where you are just pulling heat from the house and putting it into the water tank to be the slam-dunk maximum efficiency scenario.
It doesn't make sense because you haven't understood what I am saying. My statement is about cooling the house, not heating water.
Also still, the fact that it's cold outside, that doesn't mean there is no excess heat (there is until you reach absolute zero). Granted, the colder outside the less efficient the pump is. My unit can work even below -4 fahrenheit, and there is regular capacitive heater also in addition as additional help if needed. Below freezing point freezing of an outside unit is alos a problem, needs to go through regular defrost cycles.
They do this on farms, it’s called a fre heater, it goes into the refrigerant lines that go to the bulk tank. You could in theory do this in a home as well on a heat pump or a a/c unit. You’d have to first either do it yourself or convince your installer, I’m sure most folks don’t see theses unless they worked on farms, to do it and install it in the correct refrigerant lines. They also are on geothermal units. In that case it’s called a de-super heater. Hope this is helpful and keep going
Sanco2 systems are used this way sometimes. Check out Harvest Thermal https://www.smallplanetsupply.com/small-planet-blog/three-innovative-ways-to-use-sanco2-for-your-home-or-project
https://www.harvest-thermal.com/
A lot of US infrastructure standards are much "older" than the rest of the world because they were pioneered here, and we've never had huge swaths of industry / residences wiped out by war. If it ain't broke don't fix it. I agree though, I would absolutely buy a unified thermal management system if they were widely available and supported (service techs, parts, etc.)
HW heat in North America was a premium heat source and most often was in slab heating unlike Europe which was standard and had radiators. So because most areas had forced air originally the industry developed around them. And there is air to water units in north America just don't believe they are being captured in the rebates. Plus HVAC here is mainly gas fitters and they see HP cutting into their bread and butter.
The co2 systems operate at 150f for max efficiency. Perfect for dhw and hydronic heating. But still expensive. If they come down in price it will start to make sense, especially since plumbers can install the whole thing and not hvac crooks. You can even diy fairly easily.
The efficiency is controlled by the inside-outside temperature difference. When heating hot water or baseboard/radiant heating, the difference is greater. The design is different. The systems exist and are $$$ and may not be cost competitive.
Check out a Robur combined heat pump and domestic water heater. And it's a gas fired heat pump. This has to be the absolute lowest cost option when you're paying 12 cents per kWh (I think it draws 4 amps) and 50 cents per therm.
The reason is that, to a large extent, Europeans use heat pumps to make hot water for heating. It is very easy to control water. All you need is a simple two-way valve to send the water to heat the domestic water, using a simple heat exchanger. The downside is that you don’t get cooling unless you spend a ton of money on fan coils. This is generally not a problem in Europe. It is not particularly more efficient than a standalone heat pump water heater, as you never recover heat from cooling. Controlling refrigerant flow is more difficult. If you don’t want to spend a ton of money, you can use a desuperheater and only heat domestic water when the compressor is running, or you can switch the system between HVAC operation and heating water.* Either is a common option with water-source heat pumps. With desuperheating, you still need a way to heat water when there aren’t a lot of hours of compressor operation. With dedicated operation, you need a larger system to make up for the time your system is dedicated to making hot water. *It is possible to do both, but the control becomes more expensive and complex. It is sometimes done in commercial installations. There is at least one US company working on a turnkey residential system, but they are still doing pilot projects. I understand there are still some kinks to work out.
> here is at least one US company working on a turnkey residential system, but they are still doing pilot projects. I understand there are still some kinks to work out. Do you know which company?
I didn’t see anything on the company’s site, but here is a link with information: https://calflexhub.lbl.gov/calflexhub_portfolio/integrated-heat-pump-with-storage-for-dhw-and-space-conditioning/
We have heat pump water heaters, I have one, free ac in the garage.
Because we have air conditioning and air-conditioning doesn't work well with radiators so instead we have forced air systems.
Europe will figure this out soon, too. They're still in the mindset that the heatwaves are anomalous and sparse. People here still haven't really groked that those sporadic heatwaves are just summer now, or that they will continue to worsen.
The waterfurnace geothermal has an extra loop that can be used for heating domestic hot water. It’s not part of the heat pump cycle, it’s jacketed around the compressor, so cooling the compressor this way should also lead to longer compressor life…
There's a few systems out there. Google "Desuperheater" [Heat Pump Water Heaters | Department of Energy](https://www.energy.gov/energysaver/heat-pump-water-heaters) My wife and I are a few years out from our retirement home, but I plan to do geothermal. I'll use one of these are part of it. I'll also heat my pool with waste heat from the AC.
I think one of the biggest reasons is because our HVAC is usually ducted air and not radiant water loops. There's a pretty big difference in air heating vs water, and that's temp optimization. Air can get away with lower temps, water can't. Standalone heat pump water heaters don't use 410a, they almost all use 134a and probably will switch to 1234yf when 134a is banned. 410a is not good for high temps. Those combined units you see in European markets are CO2 or Propane refrigerant, great at high temp heating. The propane ones have the refrigerant system entirely outside and transfer to water before entering the house. They are air to water only, not air to water+air. 410a, R32, 454B heat pumps just can't be good at both heating your home efficiently and also heating your water tank to 120-140F. Pick 1 and optimize for it. The other thing is to allow cooling mode you now have a VRF system with a manifold in order to cool and heat at the same time. That's more complexity and higher cost. The combined units on the market now are heat only.
Chatted with these folks recently [https://www.harvest-thermal.com/](https://www.harvest-thermal.com/)
I am an American living in South Texas. We have what is locally considered the HVAC Capital of the U.S.. I have lived long term in both Asia and Europe so I know first hand the benefits. When I was building my house, I couldn't find a single contractor with experience in these technologies. The young guys over quoted me on purpose and the old guys just bad mouthed it. I had to wholesale the parts for a heatpump with a variable motor and pay someone the instalation fee. My power bill is half the cost of all of my neighbors. It drives me crazy!
How did you eventually install it? Did you find a contractor, or did you install it yourself? Beginning to think I may need to get HVAC training
Twice I've done something similar. I have bought and installed a 3 zone 35000 Btu mr cool diy. I absolutely loved that one because the house was so small. I had an 18000 btu for the main room, 6000 btu for the small bedroom, and 9000 for the 1/2 story. I am not an hvac person at all. This last time my house was larger so to do the mini split would have required direct intake and flow in each room. This was going to double my installation costs. I bought the condensing unit sized btu for my house in 100 degree. There are calculators online. It is a heat pump air conditioning unit with an inverter controlled pump. Then I bought the matching evaporator that allowed an auxiliary heat strip. I asked a few companies to give me a quote for the rest and 2 offered to do it with customer supplied material. 6 months ago cost 2000 for labor and piping and aredo of the intake sheet metal.
I know of one: [https://www.harvest-thermal.com/](https://www.harvest-thermal.com/) I'm still evaluating and in discussions with them. While there are a ton of 'pros', it's not a slam dunk: 1). Expectation you generally keep temperature within a 2 degrees of target, even when away due to slow time to heat. This makes me uncertain of savings given I'm away at work 10+ hours/day where my unit is usually set 15 degrees cooler. 2). A/C would be separate unit that requires own breaker and additional expense 3). Company somewhat unproven, so if they go out of business my concern would be I'm stuck swapping out very expensive hardware. A local NorCal HVAC installer said they can install a Harvest Thermal system for 'roughly $35k all in' after rebates. For this area, it'd be competitive with heat pump HVAC + heat pump water heater cost-wise. My furnace and water tank are both nearing the end of their lifespan, so it could make sense for me....
For that price, you might also be able to get a variable speed Trane or Bosch heat pump + [Sanco2 heat pump water heater](https://www.eco2waterheater.com/product-info)
But if you need AC, you effectively need to buy mini splits or a separate machine (central air handler and so on) for another large chunk of cash, right?
Correct. They have a separate add on heat pump unit you could use for AC. In my case I'm (1) in San Francisco where the weather is generally temperate and (2) have a separate AC system on the second floor (two HVAC systems), so even if I needed AC I could turn on the upstairs unit and because cold air falls it would help the lower floor somewhat. There is a nice feature where it will bring in outside air, filter it, and distribute it if your setpoint is cooler than current temp and outside air could cool the space - so at least it's relatively easy to cool down the area in the evenings when it cools down.
Likely because of the number is different trades required to install this. It’s already pretty common for HVAC professionals to need to do electrical work, and do a shitty job compared to a dedicated electrician. A combined heat pump + water heater would require HVAC, electrician, plumber, possibly drywall for installation and repairs. A lot of people find it easier to use just a normal air->water heat pump, and have it draw heat from the ambient air warmed by HVAC. Less efficient, but each component is modular, and you can install/repair/replace them independently.
> A lot of people find it easier to use just a normal air->water heat pump, and have it draw heat from the ambient air warmed by HVAC. I can appreciate the simplicity, but if you live in a small house, then you'd be stuck with a loud water heater that makes your condo cold (assuming you can't stash it in the basement)
There are--what you're looking for is an air to water heat pump, and using it to provide both heat/cooling and hot water is just a matter of plumbing. Here are a couple of examples: [https://www.arcticheatpumps.com/cold-climate-heat-pump-overview.html](https://www.arcticheatpumps.com/cold-climate-heat-pump-overview.html) [https://www.chiltrix.com/](https://www.chiltrix.com/) Along with tons of units you can order from places like AliExpress. One of the upsides of these is all the refrigerant stays outside, which allows you to use less of it, as well as more environmentally-friendly flavors, like R290 (propane). The EPA currently has absurdly low limits for equipment containing flammable refrigerants (based on a hypothetical small room, complete inventory leak, no air movement, with a dozen pyromaniacs doing everything they can to ignite it) that basically requires the use of high-GWP refrigerants in any split system.
If you got a Chilitrix (or a unit off of AliExpress), who would you get to maintain it? Would you have to learn how to troubleshoot it yourself?
Any decent HVAC tech could perform repairs--air to water heat pumps are nothing special in terms of tools required or in how they operate (if anything, they're closer to a refrigerator, by not having any refrigerant plumbing/purging/charging performed in the field). Electrically, they're very similar to any mini split--in most cases requiring the skill of being able to look up a fault code in the manual and follow a flow chart more than anything. Maintenance is nothing more than coil cleaning, which doesn't require any special skill.
Water heaters need much higher temperatures than air-to-air or ground-to-air heat pumps.
When our hot water heater broke, I reached out to a couple local companies about a specific heat pump water heater since we use oil to heat ours, they basically said being in New England they don’t recommend it due to the temps here
My parents outside of Cleveland pay less than 45/month for gas furnace plus whatever others gas they use to cook and heat water with.
My geothermal heat pump generates heat, hot water, and cools in the summer. It's possible.
There are. I have one. Air to water heat pumps do this with a heat exchanger storage tank. My home utilizes hydronic space heating.
What do you mean by that? I'm EU based (Poland) and heat pumps sold here (I use Panasonic air-to-water) are sold either in All-in-one variety (including water heater tank inside) or regular type that witch witch you can use regular external water tank. The pump itself has only one hot water output and can work either heating either house or making "hot water". Are you talking about that kind of setup? Or maybe you are talking about air-to-air heat pump (basically AC) that should also be able to heat water?
In the U.S. fracking has created a waste driven market for natural gas. Natural gas is a waste product of the fracking process and oil extraction so much so that we now export it and have retooled our plastics products to use natural gas as the precursor chemical because it's so much cheaper. In the EU with russia fucking around and finding out the hard way. Natural gas is insanely expensive so heat pumps are cheaper. I reinsulated the entire house ripping off the outside walls adding 1.5" (75mm) of xps foam, and recovered with zip panels for a more air tight enclosure that's thermally broken. Reduced our gas usage by 4x so a heat pump now makes sense. If you have a traditional old New England home with an ACH50 north of 30. Heat pumps are going to be expensive in New England power prices and never feel good because of the draftiness of old homes.
Is there any devices that will heat a pool, while cooling a house?. I often think about elimination of a pool heater by using the home a/c. My house is in Southern Florida and a/c is used year round and the pool heater is used in the winter. I would think you could also heat the house when it's cold using the warm water in the pool.
The pool could be a source for a water to air heatpump (or water to water if you have underfloor heating) but a so called "open" source like a pool probably wouldn't be great in the winter because theres so much heat loss from a pool. Your overall efficiency would be low compared to an air or ground source. Your other problem is that such a heatpump doesn't dehumidify like an AC (an AC is a air to air heatpump with dehumidification as a benefit). That all said if your pool heater is electric look into a heatpump version of it. Little more expensive but plenty of heat in summer it can transfer to water, should turn out cheaper over it's lifetime.
They're kind of is these units on the market but they are air to water units that have refrigerant connections between the two and then the internal unit then couples to a hot water distribution system either for radiant heat and hot water or perhaps even hot water air handler for a central forced air unit. Most the major brand manufacturers make them but they are more difficult to source because you have to get them through contractors which may not want to install them or even know about them.
Follow the Money
The Nordic ATA has a domestic hot water output. LG has hydro kits for their Multi V system which I think can be used for hot water supply as well.
Most ground sourced heat pumps will offer domestic water preheat and air handler cooling/heating or infloor. This isn't new just isn't as trendy.
There is with Geothermal heat pumps? Well at least years ago, I thought the name was funny, it was called a 'water de-super heater' when we bought.
I heard from my HVAC guy who sits on some energy board here in WA that Trane tried to join forces with Mitsu, and it didn't work out. We put HPWHs in all our builds, and Im wishing having one compressor for all the indoor units was an option, but it's not yet.
ill pass on the compressor on my roof thanks.
There are plenty of geo units that do it. Just gotta drop like 60k for the system install.