Pool Heater Sizing

[pb11186]

Hey everyone,

I'm installing a 12x25 fibreglass pool this summer. From what i am reading, the recommended heater size for natural gas is 100,000 to 150,000 btu. Anyone know is a 100,000 btu heater would suffice? Or would it be pushing it? We will be using a solar cover, also the pool exterior is insulated with spray foam insulation. Also, I am in North eastern Ontario.

Thanks!

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[Denniswiseman]

The British thermal unit is a non-SI, traditional unit of heat; it is defined as the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit. It is also part of the United States customary units
A UK gallon weighs 10lb
There are 6.25 gallons in a cubic foot
So you need to calculate the amount of UK gallons in your pool
And then find the efficiency of your boiler

[pb11186]

For future reference for anyone... Went with a 250000btu heater. Water heats up 4° to 5°F per hour. I know the standard is 1°F per hour, but thats too long of a wait for me!

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[Mikeval]

I did all kinds of research on this when our poo\spa heater went out but I no longer have it and going from memory which, well... I only heat the spa but wanted btu's for both when it came to sell the house, it would be a benefit. It seemed at the time, doing the straight math, the recommended BTU's were way over what the formula spit out. But it came down to air temps, the depth layout of the pool, the temperature of where you are, etc, Heating a gallon of water 1 degree via the formula does not take into account where that water is, but rather a perfect room temp lab setting so to speak. I don't have my notes but it was something like 30% more btu's than the formula spit out.