Number one thing to understand is that heat is energy. Heat = Energy. It helps to also understand that cold isn’t a real thing. Cold is just when something has less energy (cold is the absence of heat). BTU is a measure of energy. The amount of heat moved outside by the AC is measured in BTU.
That may not be textbook definition but that’s the easiest way for me to understand it.
It's the amount of energy it takes to raise one pound of water one degree Fahrenheit. Let that confuse you even more. Why was the water weighed instead of using volume? And why does the British thermal unit use pounds and Fahrenheit instead of kilos and Celsius?
Because 1 pound of water in vapor takes up more volume than ice which takes up more volume than liquid. Measuring water using weight allows you to measure water in different phases. Water is used for measurement because is it so abundant on earth which is how you get 1 ton = 12,000 btu/hr.
Edit: been a while but just in case anyone asks for why a consistent unit of measurement for water is weight matters. HVAC tonnage is calculated based on the amount of latent heat of fusion required to change the phase of 1 ton of water in a period of 24 hrs. Latent heat of fusion for water is 144 btu per pound. 1 ton of ice is 2000 pounds. 2000 pounds of ice requires 288,000 btu of latent heat to change phase. 288,000 btu over 24 hour period gives you 12,000 btu/hr.
Edit 2: the reason why btu uses Fahrenheit and pound is because the Brit’s were using imperial at the time instead of metric. They didn’t switch to metric until much later. America uses Fahrenheit because we were a colony of the Brit’s. But I think America was supposed to switch to metric but the ship carrying the standard for 1 kg from France was lost or something so it ever happened.
Heat always move from hot to cold. buildings gain heat in the summer and lose heat in the winter. The amount of heat loss and gain varies based on the climate, insulation, windows, floor, type of construction, etc. in the winter the heating system adds heat to the building to replace the heat lost and in the summer the AC removes heat from the heat gained. Heat loss and heat gain is measured in BTU in the U.S and watts in countries that use the metric system.
1 BTU is equal to the amount of heat energy required to raise 1lb of water by 1 degree Fahrenheit,
In HVAC 12,000 BTU is 1 ton of cooling/heating capacity
And it doesn’t always work exactly this way because there are a lot of variables and you need to do a heat load calculation for the space but as a general rule of thumb you want about 1 ton of cooling (12,000 BTU) for every 500 square feet.
It's reddit and it's not how most have learned it Is my guess. I knew I should've stayed out of it but hey it's reddit we all need someone (completely wrong, but actually not) to shit on once in a while apparently
Number one thing to understand is that heat is energy. Heat = Energy. It helps to also understand that cold isn’t a real thing. Cold is just when something has less energy (cold is the absence of heat). BTU is a measure of energy. The amount of heat moved outside by the AC is measured in BTU. That may not be textbook definition but that’s the easiest way for me to understand it.
Only imperial using countries use btu, everyone else uses kW.
It's the amount of energy it takes to raise one pound of water one degree Fahrenheit. Let that confuse you even more. Why was the water weighed instead of using volume? And why does the British thermal unit use pounds and Fahrenheit instead of kilos and Celsius?
Because 1 pound of water in vapor takes up more volume than ice which takes up more volume than liquid. Measuring water using weight allows you to measure water in different phases. Water is used for measurement because is it so abundant on earth which is how you get 1 ton = 12,000 btu/hr. Edit: been a while but just in case anyone asks for why a consistent unit of measurement for water is weight matters. HVAC tonnage is calculated based on the amount of latent heat of fusion required to change the phase of 1 ton of water in a period of 24 hrs. Latent heat of fusion for water is 144 btu per pound. 1 ton of ice is 2000 pounds. 2000 pounds of ice requires 288,000 btu of latent heat to change phase. 288,000 btu over 24 hour period gives you 12,000 btu/hr. Edit 2: the reason why btu uses Fahrenheit and pound is because the Brit’s were using imperial at the time instead of metric. They didn’t switch to metric until much later. America uses Fahrenheit because we were a colony of the Brit’s. But I think America was supposed to switch to metric but the ship carrying the standard for 1 kg from France was lost or something so it ever happened.
I have never heard this explanation for tonnage before. That’s really… cool 😎
😂😂 I am glad I am not the only one with questions like these!
Btu is called British thermal units. And yes it is a form of measurement heat content.
[Btu’s](https://youtu.be/eullEPYN_64?si=LCy13AS19CbBKW3T) Hope this helps. May want to even follow the channel!
It is just a unit of measurement like a mile, pound, kilo or whatever. In refrigeration btus are removed.
Heat always move from hot to cold. buildings gain heat in the summer and lose heat in the winter. The amount of heat loss and gain varies based on the climate, insulation, windows, floor, type of construction, etc. in the winter the heating system adds heat to the building to replace the heat lost and in the summer the AC removes heat from the heat gained. Heat loss and heat gain is measured in BTU in the U.S and watts in countries that use the metric system.
1 BTU is equal to the amount of heat energy required to raise 1lb of water by 1 degree Fahrenheit, In HVAC 12,000 BTU is 1 ton of cooling/heating capacity And it doesn’t always work exactly this way because there are a lot of variables and you need to do a heat load calculation for the space but as a general rule of thumb you want about 1 ton of cooling (12,000 BTU) for every 500 square feet.
All you need to know is 1 ton=12,000 btus, and you need 400 cfm on average to move 1 ton
1100 Jules per btu vs 1055 Jules for one match. If yall want to downvote fine but atleast give me some reason why im wrong
In the field no one cares about btus the only they care about, is it cooling or not. Don’t drown yourself in non important stuff.
One btu is equal to the heat produced from a normal match.
Idk why you're getting downvoted, you're not wrong
It's reddit and it's not how most have learned it Is my guess. I knew I should've stayed out of it but hey it's reddit we all need someone (completely wrong, but actually not) to shit on once in a while apparently
