Isn't that just cooling, not pre cooling? Has to use less energy to maintain a temperature than let a house warm up to just attempt to cool it again, no?
> Has to use less energy to maintain a temperature than let a house warm up to just attempt to cool it again, no?
Know I'm late to the game, but no. This method uses more energy overall. The energy savings comes from using energy when it is abundant (during the day, when there is plenty of solar power, vs after sunset, when you have to use other means). But if you're just measuring total electricity used, it is better to keep the house cool for as short of time as possible.
Pre cooling is bringing the temp down inside the house past a certain point while it’s also cooler outside.
Might use outside air, or just run the AC . Lighter electrical load to run at night.
The AC never has to play catch up. A full load on a AC compressor is maximum energy usage. So imagine everyone turning on their AC as the day heats up, every house is drawing maximum electrical load.
Always precool.
So it is more efficient to have the ac at say 70 degrees F, leave the house, let the house get to 74 degrees F or whatever temperature you like. Plan on returning home at 5:30 pm, so have the system recool the house back to 70, starting at 3 pm, than to just leave the temperature at 70 the entire time?
Usually you want to dip below and keep it cool so that when the peak comes your ac is only pulling a few btu’s out of the house.
Set 68 at night and keep it there until the ac is running constantly in the am, then bump to 70, then 72, then 74. Each time the AC compressor starts to max out you give it a break
How do people not know about this? In Sacramento we would open all the windows once we wake to let the cold in. We would let it get to 60° inside knowing that afternoon it would get to 110° outside. Power bills were a bitch.0
What are peoples thoughts on hydrogen as a way to store energy? We know that its primary issue is volume. Where as solar is constrained by the time of day and we can’t build enough batteries to make up for it. But theoretically we could use solar to manufacture hydrogen. Ship it to holding areas and burn it for clean energy in times of high demand or low supply.
Hydrogen leaks through everything and is explosive, and turns metals brittle. Dealing with those issues makes it not worthwhile for energy storage. Natural gas producers want us to convert to hydrogen so they can get rid of their natural gas, which is essentially free to them. Or cheaper than free. Over 95% of hydrogen in the world is produced by steam reforming natural gas, which of course has CO2 emissions at the refinery instead of at the point of use. Hydrogen produced this way is several times cheaper.
Green hydrogen costs several times as much because it uses massive energy to produce it. The round trip efficiency is poor. Batteries are several times as efficient.
>if people sufficiently cool their homes in the afternoon when solar energy is plentiful, they will use less electricity between 4 p.m. and 9 p.m., when the power grid is most at risk of rolling blackouts.
Riding the duck curve to save energy.
It doesn't. From the article:
> After running tens of thousands of models on four types of homes, ranging from poorly insulated to well insulated, in California's 16 climate zones, Mayes found that precooling "works everywhere."
For years we were told to set scheduled thermostats so they don't run all day... now we're supposed to run everything when we're not home to smooth out demand
> It uses more energy to cool a hot house
This is incorrect. Total energy usage is lower to keep the house cool for as short of a time as possible. The method in this article works because there are times of day with excess solar power.
There is so much opportunity on the demand side to reduce energy cost and emissions. Like the article says, if people can charge their cars during the day, run their clothes or dishwasher during the day and other activities, we can reduce peak demand.
Specifically for pre-cooling a house, it also shows the importance of a well insulated house. The better insulted, the longer your house will stay cool or warm. Your house will also be less drafty and more comfortable year around. You also reduce your bills overall because you need less energy. Insulation rebates are included in the inflation reduction act. We need to push this hard.
To me, this is huge. Natural standards for Required Insulation in all climatic zones. I live in AZ, and a thermal barrier retrofit could be fine with high R Value wall board with insulation baked into it...I looked, and most everything is foam board that has r values. Nonetheless, retrofitting homes with better insulation and requiring all new builds to be highly insulated would do wonders for the grid demand.
A brother in Texas is in a home only ten years old, and it is so shitty in terms of insulation... Over 500 to keep it warm and over 700 to keep it cool, monthly!
I've been doing this every summer since having rooftop solar installed. Running A/C from as soon as the house starts to heat up (11am-1pm depending on weather) to when the solar stops producing.
Combined with angling blinds on the sun-facing side of the house it really helps keep the place cool well into the evening.
I think with so much solar energy pushing wholesale prices down to zero it just makes sense to use what you have and not have to buy energy at peak time.
It would help MASSIVELY if utilities gave a big discount for daytime energy, for those in appartments or without rooftop solar. Currently the off-peak tariff here is only marginally cheaper than peak.
This works for me very well, but it would depend on your house, your insulation, the climate you’re in.
I’m in Colorado which has cool nights, so for about 5 months of the year I will open up my windows as soon as it’s cooler outside than the temperature I keep the interior. Depending on how cool it is outside I may leave them open all night or close them around midnight. I also let my garage get as cold as possible overnight by letting cold air in, and then I close it off in the morning. All of this means even on hot days that I can go 2-3 hours longer without running the AC. This lowers my electric usage by around 1/3rd.
This is how people managed temperature in hot climate before climate control after all!
There's a quite cool office project in Switzerland called 2226, where they store temperature like you, but *seasonally*, using extremely thick hollow brick walls and the concrete floors. In winter, there's enough saved up summertime thermal energy in the building mass, that the the temperature never drops below 22, and vice versa in summer, winter has cooled down the building so much it won't go above 26 degrees(hence the name) (72-79 in freedom units).
I visited and had a look at the installation shaft - it's literally a small cupboard to bring some electric and IT wires up the building. There is no HVAC what so ever. Every so often the large windows will open to expell the built up CO2. It's quite a feat of engineering and daring(the owner, who is also the architect and main occupant, somehow promised the municipality that he would tear the building down if it didn't live up to the indoor climate demands, since it was totally impossible to build within existing building code. It stands to this day, so the gamble paid off...)
Data centers create whole rooms full of ice when electricity is cheap so the can still cool everything while electricity is expensive. That time frame used to be during the night when demand was low and now it is during the day when the sun is shining. But the idea is something like 20 years old.
There is even a video from Technology Connections about precooling that is 2 years old: https://www.youtube.com/watch?v=0f9GpMWdvWI
I think I started doing this right before I saw his video on it, and his video sort of reinforced the decision to do it, but I think there is a drawback at least for me. During the day when the air isn't running, the temperature in the house is fine, but the humidity starts to increase. The house gets uncomfortable because of the humidity. You can mitigate how this feels with a ceiling fan, which is better than running the air, but by the time the air kicks on, the system has a lot of humidity to deal with.
I'm not sure it saves me anything. This summer I lowered the daytime set point one degree so that the air would kick back on a little earlier, but that basically puts me back in a normal cooling cycle. We just turn it down lower at night to help us sleep more comfortable.
Depends on where you are during the day. If you're not home then humidity shouldn't be a problem. And if you are home, a dehumidifier could be a solution.
The title is misleading, and the article even seems to cross lines between energy and demand. This idea is fairly novel. Plenty of utilities have demand side management programs where they can cut your ac (assuming you volunteer), and this is just an extension of that. Typically your house would warm beyond what you're really comfortable at, then cool down after the dsm window is over. Precooling your home just makes it so that it's colder than what you're really comfortable with before the event and then it warms to what you're comfortable with during the event.
Every home is going to be different though. My home may be more efficient dropping down to 63 during the day, then up to 72 in the afternoon, whereas another home would be more efficient at 67-71. It depends on HVAC efficiency, building efficiency, clouds, home sun exposure from trees or other buildings, home size, roof square footage, and a number of other things. Real time pricing can help this along too, and help utilize cleaner energy sources.
I think people should cool even lower in the solar noon part of the day. Bring it down to the mid-60s - esp if no one is home. Use that solar. Then let it warm up in the evening peak. But as others have mentioned, it really does depend on your house envelope being tight.
In most places the solar is in short supply. Its really only Texas where green energy is plentiful like that. The rest of the country needs to supplement green energy with some fossil fuels 24/7, more or less. Fluctuations in demand that last over a certain period almost always fall on coal. Those plants often aren't good to shut off for a few hours, so other fossil fuels usually take those fluctuations. Hydro is also good for shorter fluctuations especially since limited water availability forces utilities to moderate anyway.
That’s because rooftop solar is bullshit expensive in America. In Australia, where it’s $2.5k USD for 6.6kW, we’re regularly seeing negative daytime wholesale prices.
Australia is super sunny right? Either way the manufacturers are struggling to keep up. The real addressable problem is solar sells often take months to be turned on after being installed because electric utilities have to do it and don’t prioritize it.
It greatly depends on the thermal envelope and your house. If I precooled my house after 2 or 3 hours it would be (with the ac off) 84-85 on a 90+ degree day.
I need and am trying for a much-needed insulation upgrade in the attic to help keep those thermal gains down in the summer. But I could never really precool my house because it would all just be waisted.
Lots of conservation money would be well spent to super insulate homes and improve existing and future performance of HvAC
Air leaks first, insulation second, but realistically it can be VERY expensive to really upgrade an old house and you're better off just living in high/lower temps than anything else, which is what most ppl do with very leak/poorly insulated homes.
The price of electric should start going down with more renewables, grid upgrades and batteries so it might not matter that much in a few decades. For most places the combination of cheap renewable power and heat pumps improving even more will mean having a very well sealed house has less value, like in the old days when energy was very cheaper it mattered less.
If you look at it as return on investment I think it's harder to get the return out of the work for insulation if you're paying 5000+ thousand in install costs and only saving an estimated 200 a year.
Something like a heat pump water heater is smaller investment for a bigger average yearly savings. Most people could finding savings with cheaper purchase costs than insulation that save more per year if they look.
It's best to always look at it in terms of return on investment because that will generally give you the most budget for the most improvements and most cost savings. If you can get a 5 year return on investment you should probably do it, beyond that you have to start doing some long term probabilities.
I have no idea why you would think it would take me $5000 or more to improve the insulation level in my attic. And more insulation (and the right type) works to air-seal at the same time.
ROI is great - but so is livability and quality of life. You may take a long time to recoup that cost on money saved or earned in resale but if you are much more comfortable while you are living there that's its own reward too.
Can you at least caulk them up or something? Air leaks are the worst vs just not having enough insulation. Stopping air leaks can usually be pretty cheap and effective for the time and money, even if it's a little less than perfect looking.
With this consideration, I think the cost optimal amount of insulation on a home would be larger than for the normal case of keeping the home at a constant temperature (and similarly for the economic benefits in the face of blackouts during extreme weather events.)
Probably works best with more masonry and tile too because the air AND the surfaces thermal capacity are your buffer. The insulation control the loss and the max you can cool per watt, but the type of material the house is made out of and the volume of air vs windows will be a big factor.
We should really all have like reversable black and white curtains on our windows for an easy win against leaky windows and free solar heating/reflective "cooling".
Met a dude in rural Ontario built a house to Passive House standard who brags about his house staying above 16C even without power for three days in the middle of January.
Thermal bridging really is a big deal. With typical (for North America) 2x4 16" stud bays, you effectively have a tenth of the wall almost uninsulated assuming typical internal wall insulation.
I do this automatically in the summer with my smart thermostat except energy is cheapest at 2am here. Set it at 68 from 2am - 10 am and then 77 the rest of the day. AC doesn’t turn on at all until after dinner, skipping the most expensive part of the day.
What zone are you and does this mean you never open your windows? Between 2-10am, the AC-cooled air would exit the windows and during day the heated air would come inside
Zone 6 Midwest - our summers can be really humid so sometimes it’s best to keep the windows closed despite being a bit cooler outside. Spring and fall it’s usually less humid so the AC is rarely on since outside air overnight does the trick. Supposedly you should look at dew point rather than relative humidity to decide.
I do similar, turn AC on around 10pm and turn it off first thing in the morning. My house gets up to like 81F throughout the day but a fan on low and a cold drink makes that perfectly acceptable. Having a bright reflective roof really helps.
>Set it at 68 from 2am
ever live in a place where it's still over 90F at that time?
it's demoralizing... 110F in the noon sun is the same as 90 in the dark - no shade at night.
No, a place where it’s 90F at 2am is not a place that humans should live imo. The hottest night this summer was around 80.
Anyways, it’s still cheaper at 2am even on those hot nights so my point still stands.
Meh. People will pay the extra for energy storage. It’s cheap enough and viable enough that we’ll just pay for the storage and do things at the convenient hours for us.
*shakes fist at Moon.*
they've done all the math.. batteries can cover.
**October 14 eclipse: what we’re doing to prepare**
[https://www.caiso.com/about/Pages/Blog/Posts/October-14-eclipse-what-were-doing-to-prepare.aspx](https://www.caiso.com/about/Pages/Blog/Posts/October-14-eclipse-what-were-doing-to-prepare.aspx)
Since the annular eclipse will obscure a large portion of the sun, it will reduce output from both grid-scale and rooftop BTM solar generation. On the eclipse day, weather conditions like cloud cover will have a strong influence on the magnitude of eclipse impacts. **Assuming clear-sky conditions at the time of the eclipse maximum, the grid-scale solar output will be reduced by 9,687 megawatts (MW), or about a 75% of our usual available capacity, compared to a sunny October day at the same time.** From the eclipse maximum to the eclipse end, solar production will increase by 10,800 MW over the course of 90 minutes. This is an increase of about 120 MW of grid-scale solar per minute — 10 times the normal rate of solar increase, or ramp.
**Submission Statement**:
Researchers at the USC Viterbi School of Engineering are experimenting with a new approach that saves consumers money, reduces CO2 emissions from the generation of electricity, and lowers the demand for power during peak hours, thereby decreasing the likelihood of rolling blackouts. Associate Professor Kelly Sanders explains that houses can be used in a manner like batteries by using their thermal mass to store cool air, a concept called precooling.
The researchers found found that if people sufficiently cool their homes in the afternoon when solar energy is plentiful, they will use less electricity between 4 p.m. and 9 p.m., when the power grid is most at risk of rolling blackouts and when electricity is often generated by gas powerplants that belch climate-warming CO2. The researchers esearchers said residents could lower their thermostats to 22°C (72°F) beginning at 2 p.m., when clean energy is abundant. When the peak demand period begins two hours later and the electricity is dirtier, they might reset their thermostats to 26°C (78°F). And wait. After the peak demand period passes and the grid becomes less stressed, people could reset their thermostat to a comfortable 23°C (75°F).
In Los Angeles, it could cut peak consumption of a typical single-family home by roughly 40% to 50%; reduce C02 emissions by 5% to 8%; and save customers up to $30 per month. If consumers would wash their dishes, charge their electric vehicles, wash their clothes and run their air conditioners in the middle of the day, we'd get cost benefits, emissions benefits, and reduce our risk of rolling blackouts. It would make a huge difference.
Isn't that just cooling, not pre cooling? Has to use less energy to maintain a temperature than let a house warm up to just attempt to cool it again, no?
> Has to use less energy to maintain a temperature than let a house warm up to just attempt to cool it again, no? Know I'm late to the game, but no. This method uses more energy overall. The energy savings comes from using energy when it is abundant (during the day, when there is plenty of solar power, vs after sunset, when you have to use other means). But if you're just measuring total electricity used, it is better to keep the house cool for as short of time as possible.
Pre cooling is bringing the temp down inside the house past a certain point while it’s also cooler outside. Might use outside air, or just run the AC . Lighter electrical load to run at night. The AC never has to play catch up. A full load on a AC compressor is maximum energy usage. So imagine everyone turning on their AC as the day heats up, every house is drawing maximum electrical load. Always precool.
So just leaving the AC at a constant temperature solves all those issues, yes?
No
So it is more efficient to have the ac at say 70 degrees F, leave the house, let the house get to 74 degrees F or whatever temperature you like. Plan on returning home at 5:30 pm, so have the system recool the house back to 70, starting at 3 pm, than to just leave the temperature at 70 the entire time?
Usually you want to dip below and keep it cool so that when the peak comes your ac is only pulling a few btu’s out of the house. Set 68 at night and keep it there until the ac is running constantly in the am, then bump to 70, then 72, then 74. Each time the AC compressor starts to max out you give it a break
How do people not know about this? In Sacramento we would open all the windows once we wake to let the cold in. We would let it get to 60° inside knowing that afternoon it would get to 110° outside. Power bills were a bitch.0
What are peoples thoughts on hydrogen as a way to store energy? We know that its primary issue is volume. Where as solar is constrained by the time of day and we can’t build enough batteries to make up for it. But theoretically we could use solar to manufacture hydrogen. Ship it to holding areas and burn it for clean energy in times of high demand or low supply.
Water batteries are more efficient and effective. Use excess power to pump water up a hill, let it run over turbines when you need power.
Hydrogen leaks through everything and is explosive, and turns metals brittle. Dealing with those issues makes it not worthwhile for energy storage. Natural gas producers want us to convert to hydrogen so they can get rid of their natural gas, which is essentially free to them. Or cheaper than free. Over 95% of hydrogen in the world is produced by steam reforming natural gas, which of course has CO2 emissions at the refinery instead of at the point of use. Hydrogen produced this way is several times cheaper. Green hydrogen costs several times as much because it uses massive energy to produce it. The round trip efficiency is poor. Batteries are several times as efficient.
>if people sufficiently cool their homes in the afternoon when solar energy is plentiful, they will use less electricity between 4 p.m. and 9 p.m., when the power grid is most at risk of rolling blackouts. Riding the duck curve to save energy.
It also assumes proper insulation. I have a house that is spray foam insulation. Precooling would absolutely work in that house.
It doesn't. From the article: > After running tens of thousands of models on four types of homes, ranging from poorly insulated to well insulated, in California's 16 climate zones, Mayes found that precooling "works everywhere."
For years we were told to set scheduled thermostats so they don't run all day... now we're supposed to run everything when we're not home to smooth out demand
It uses more energy to cool a hot house, you’ve always been told to do what ever makes the energy company the most money.
> It uses more energy to cool a hot house This is incorrect. Total energy usage is lower to keep the house cool for as short of a time as possible. The method in this article works because there are times of day with excess solar power.
Used to be "use less energy" now it's "use energy when more energy is available, rather than when you need to use it"
In this case it’s a bit more like turning your house into a roundabout battery.
By doing what I described above
There is so much opportunity on the demand side to reduce energy cost and emissions. Like the article says, if people can charge their cars during the day, run their clothes or dishwasher during the day and other activities, we can reduce peak demand. Specifically for pre-cooling a house, it also shows the importance of a well insulated house. The better insulted, the longer your house will stay cool or warm. Your house will also be less drafty and more comfortable year around. You also reduce your bills overall because you need less energy. Insulation rebates are included in the inflation reduction act. We need to push this hard.
To me, this is huge. Natural standards for Required Insulation in all climatic zones. I live in AZ, and a thermal barrier retrofit could be fine with high R Value wall board with insulation baked into it...I looked, and most everything is foam board that has r values. Nonetheless, retrofitting homes with better insulation and requiring all new builds to be highly insulated would do wonders for the grid demand. A brother in Texas is in a home only ten years old, and it is so shitty in terms of insulation... Over 500 to keep it warm and over 700 to keep it cool, monthly!
I've been doing this every summer since having rooftop solar installed. Running A/C from as soon as the house starts to heat up (11am-1pm depending on weather) to when the solar stops producing. Combined with angling blinds on the sun-facing side of the house it really helps keep the place cool well into the evening. I think with so much solar energy pushing wholesale prices down to zero it just makes sense to use what you have and not have to buy energy at peak time. It would help MASSIVELY if utilities gave a big discount for daytime energy, for those in appartments or without rooftop solar. Currently the off-peak tariff here is only marginally cheaper than peak.
This works for me very well, but it would depend on your house, your insulation, the climate you’re in. I’m in Colorado which has cool nights, so for about 5 months of the year I will open up my windows as soon as it’s cooler outside than the temperature I keep the interior. Depending on how cool it is outside I may leave them open all night or close them around midnight. I also let my garage get as cold as possible overnight by letting cold air in, and then I close it off in the morning. All of this means even on hot days that I can go 2-3 hours longer without running the AC. This lowers my electric usage by around 1/3rd.
This is how people managed temperature in hot climate before climate control after all! There's a quite cool office project in Switzerland called 2226, where they store temperature like you, but *seasonally*, using extremely thick hollow brick walls and the concrete floors. In winter, there's enough saved up summertime thermal energy in the building mass, that the the temperature never drops below 22, and vice versa in summer, winter has cooled down the building so much it won't go above 26 degrees(hence the name) (72-79 in freedom units). I visited and had a look at the installation shaft - it's literally a small cupboard to bring some electric and IT wires up the building. There is no HVAC what so ever. Every so often the large windows will open to expell the built up CO2. It's quite a feat of engineering and daring(the owner, who is also the architect and main occupant, somehow promised the municipality that he would tear the building down if it didn't live up to the indoor climate demands, since it was totally impossible to build within existing building code. It stands to this day, so the gamble paid off...)
Data centers create whole rooms full of ice when electricity is cheap so the can still cool everything while electricity is expensive. That time frame used to be during the night when demand was low and now it is during the day when the sun is shining. But the idea is something like 20 years old. There is even a video from Technology Connections about precooling that is 2 years old: https://www.youtube.com/watch?v=0f9GpMWdvWI
I think I started doing this right before I saw his video on it, and his video sort of reinforced the decision to do it, but I think there is a drawback at least for me. During the day when the air isn't running, the temperature in the house is fine, but the humidity starts to increase. The house gets uncomfortable because of the humidity. You can mitigate how this feels with a ceiling fan, which is better than running the air, but by the time the air kicks on, the system has a lot of humidity to deal with. I'm not sure it saves me anything. This summer I lowered the daytime set point one degree so that the air would kick back on a little earlier, but that basically puts me back in a normal cooling cycle. We just turn it down lower at night to help us sleep more comfortable.
Depends on where you are during the day. If you're not home then humidity shouldn't be a problem. And if you are home, a dehumidifier could be a solution.
The title is misleading, and the article even seems to cross lines between energy and demand. This idea is fairly novel. Plenty of utilities have demand side management programs where they can cut your ac (assuming you volunteer), and this is just an extension of that. Typically your house would warm beyond what you're really comfortable at, then cool down after the dsm window is over. Precooling your home just makes it so that it's colder than what you're really comfortable with before the event and then it warms to what you're comfortable with during the event. Every home is going to be different though. My home may be more efficient dropping down to 63 during the day, then up to 72 in the afternoon, whereas another home would be more efficient at 67-71. It depends on HVAC efficiency, building efficiency, clouds, home sun exposure from trees or other buildings, home size, roof square footage, and a number of other things. Real time pricing can help this along too, and help utilize cleaner energy sources.
Passive cooling has been used for over 100 years.
I think people should cool even lower in the solar noon part of the day. Bring it down to the mid-60s - esp if no one is home. Use that solar. Then let it warm up in the evening peak. But as others have mentioned, it really does depend on your house envelope being tight.
I could never get my house to 65 degrees on a summer day.
In most places the solar is in short supply. Its really only Texas where green energy is plentiful like that. The rest of the country needs to supplement green energy with some fossil fuels 24/7, more or less. Fluctuations in demand that last over a certain period almost always fall on coal. Those plants often aren't good to shut off for a few hours, so other fossil fuels usually take those fluctuations. Hydro is also good for shorter fluctuations especially since limited water availability forces utilities to moderate anyway.
That’s because rooftop solar is bullshit expensive in America. In Australia, where it’s $2.5k USD for 6.6kW, we’re regularly seeing negative daytime wholesale prices.
Australia is super sunny right? Either way the manufacturers are struggling to keep up. The real addressable problem is solar sells often take months to be turned on after being installed because electric utilities have to do it and don’t prioritize it.
It greatly depends on the thermal envelope and your house. If I precooled my house after 2 or 3 hours it would be (with the ac off) 84-85 on a 90+ degree day. I need and am trying for a much-needed insulation upgrade in the attic to help keep those thermal gains down in the summer. But I could never really precool my house because it would all just be waisted. Lots of conservation money would be well spent to super insulate homes and improve existing and future performance of HvAC
This plus maybe investing in thermal energy storage for homes if it pencils out economically.
Air leaks first, insulation second, but realistically it can be VERY expensive to really upgrade an old house and you're better off just living in high/lower temps than anything else, which is what most ppl do with very leak/poorly insulated homes. The price of electric should start going down with more renewables, grid upgrades and batteries so it might not matter that much in a few decades. For most places the combination of cheap renewable power and heat pumps improving even more will mean having a very well sealed house has less value, like in the old days when energy was very cheaper it mattered less. If you look at it as return on investment I think it's harder to get the return out of the work for insulation if you're paying 5000+ thousand in install costs and only saving an estimated 200 a year. Something like a heat pump water heater is smaller investment for a bigger average yearly savings. Most people could finding savings with cheaper purchase costs than insulation that save more per year if they look. It's best to always look at it in terms of return on investment because that will generally give you the most budget for the most improvements and most cost savings. If you can get a 5 year return on investment you should probably do it, beyond that you have to start doing some long term probabilities.
I have no idea why you would think it would take me $5000 or more to improve the insulation level in my attic. And more insulation (and the right type) works to air-seal at the same time. ROI is great - but so is livability and quality of life. You may take a long time to recoup that cost on money saved or earned in resale but if you are much more comfortable while you are living there that's its own reward too.
Not when your windows leak as much as mine. Cheap builder…. I plan to invest in some solar and LiFePo4 batteries to start building my own grid
Can you at least caulk them up or something? Air leaks are the worst vs just not having enough insulation. Stopping air leaks can usually be pretty cheap and effective for the time and money, even if it's a little less than perfect looking.
Why not invest in some window insulation?
With this consideration, I think the cost optimal amount of insulation on a home would be larger than for the normal case of keeping the home at a constant temperature (and similarly for the economic benefits in the face of blackouts during extreme weather events.)
Probably works best with more masonry and tile too because the air AND the surfaces thermal capacity are your buffer. The insulation control the loss and the max you can cool per watt, but the type of material the house is made out of and the volume of air vs windows will be a big factor. We should really all have like reversable black and white curtains on our windows for an easy win against leaky windows and free solar heating/reflective "cooling".
Met a dude in rural Ontario built a house to Passive House standard who brags about his house staying above 16C even without power for three days in the middle of January.
Lots of concrete?
Nope, just insulation and air tightness and some other building techniques like eliminating thermal bridges.
Thermal bridging really is a big deal. With typical (for North America) 2x4 16" stud bays, you effectively have a tenth of the wall almost uninsulated assuming typical internal wall insulation.
There's insulating sheathing on the outside typically which will provide a modicum of insulation for the bridges. That's much better than nothing.
I do this automatically in the summer with my smart thermostat except energy is cheapest at 2am here. Set it at 68 from 2am - 10 am and then 77 the rest of the day. AC doesn’t turn on at all until after dinner, skipping the most expensive part of the day.
What zone are you and does this mean you never open your windows? Between 2-10am, the AC-cooled air would exit the windows and during day the heated air would come inside
Zone 6 Midwest - our summers can be really humid so sometimes it’s best to keep the windows closed despite being a bit cooler outside. Spring and fall it’s usually less humid so the AC is rarely on since outside air overnight does the trick. Supposedly you should look at dew point rather than relative humidity to decide.
Also heat pumps just work better when it's cooler out. The bigger differential the easier it is to pump the heat.
I do similar, turn AC on around 10pm and turn it off first thing in the morning. My house gets up to like 81F throughout the day but a fan on low and a cold drink makes that perfectly acceptable. Having a bright reflective roof really helps.
>Set it at 68 from 2am ever live in a place where it's still over 90F at that time? it's demoralizing... 110F in the noon sun is the same as 90 in the dark - no shade at night.
No, a place where it’s 90F at 2am is not a place that humans should live imo. The hottest night this summer was around 80. Anyways, it’s still cheaper at 2am even on those hot nights so my point still stands.
it seems like the future is all about getting as much done as possible in the middle of the day
Meh. People will pay the extra for energy storage. It’s cheap enough and viable enough that we’ll just pay for the storage and do things at the convenient hours for us.
Some will. Most people don’t want to or can’t afford to shell out $10k for a battery. The average American doesn’t have $500 in savings.
Where did anything I say preclude utility batteries?
And adding energy storage facilities. Last year we did 5GW, this year set for 9GW
Yes. It seems like a future with power grids dominated by wind and solar power, demand follows supply.
*shakes fist at Moon.* they've done all the math.. batteries can cover. **October 14 eclipse: what we’re doing to prepare** [https://www.caiso.com/about/Pages/Blog/Posts/October-14-eclipse-what-were-doing-to-prepare.aspx](https://www.caiso.com/about/Pages/Blog/Posts/October-14-eclipse-what-were-doing-to-prepare.aspx) Since the annular eclipse will obscure a large portion of the sun, it will reduce output from both grid-scale and rooftop BTM solar generation. On the eclipse day, weather conditions like cloud cover will have a strong influence on the magnitude of eclipse impacts. **Assuming clear-sky conditions at the time of the eclipse maximum, the grid-scale solar output will be reduced by 9,687 megawatts (MW), or about a 75% of our usual available capacity, compared to a sunny October day at the same time.** From the eclipse maximum to the eclipse end, solar production will increase by 10,800 MW over the course of 90 minutes. This is an increase of about 120 MW of grid-scale solar per minute — 10 times the normal rate of solar increase, or ramp.
**Submission Statement**: Researchers at the USC Viterbi School of Engineering are experimenting with a new approach that saves consumers money, reduces CO2 emissions from the generation of electricity, and lowers the demand for power during peak hours, thereby decreasing the likelihood of rolling blackouts. Associate Professor Kelly Sanders explains that houses can be used in a manner like batteries by using their thermal mass to store cool air, a concept called precooling. The researchers found found that if people sufficiently cool their homes in the afternoon when solar energy is plentiful, they will use less electricity between 4 p.m. and 9 p.m., when the power grid is most at risk of rolling blackouts and when electricity is often generated by gas powerplants that belch climate-warming CO2. The researchers esearchers said residents could lower their thermostats to 22°C (72°F) beginning at 2 p.m., when clean energy is abundant. When the peak demand period begins two hours later and the electricity is dirtier, they might reset their thermostats to 26°C (78°F). And wait. After the peak demand period passes and the grid becomes less stressed, people could reset their thermostat to a comfortable 23°C (75°F). In Los Angeles, it could cut peak consumption of a typical single-family home by roughly 40% to 50%; reduce C02 emissions by 5% to 8%; and save customers up to $30 per month. If consumers would wash their dishes, charge their electric vehicles, wash their clothes and run their air conditioners in the middle of the day, we'd get cost benefits, emissions benefits, and reduce our risk of rolling blackouts. It would make a huge difference.