100,000 btu how much will that heat?

Question

100,000 btu how much will that heat?

Answer 1

You genrally need 20 BTU per square foot of area if you get snow in your area. If the temprature outside gets as low as -10 F in the winter you're going to need about 25 BTU per foot

Answer 2

Way too many factors to give a generic answer. It depends on the temperatures where you live, windows, insulation, area, in other words the heat loss in the home.  

Be aware that old furnaces were not very efficient. It can be as low 60-65%. So a 90% efficient 90k BTU unit puts more heat in the house than a 110k BTU old one.

I find that oversizing with a higher efficiency furnace is a much more common and bigger problem than undersized. Bigger is NOT better in most cases. And with higher efficiencies even the same size is too big.

The size and design of the ducting must be able to remove all the heat from the furnace or the furnace will overheat short cycling off on limits. In that case you risk cracking a heat exchanger and it hurts your efficiency running hot because more heat goes up the stack.

A smaller furnace simply runs more. And these days with the new furnaces they run them at a much lower heat rise (outlet temperature) and run them almost twice as much as the old ones. This isn't bad because it circulates more air giving you a more even heat.

With a replacement, an estimator usually has a computer program to tell them the figures and they input all the factors they can, like windows and square footage.

The BTU "input" rating of your old furnace will be on the model number plate if want to compare but then the efficiency rating has to be factored.

If you go up in efficiency, you must go down in BTU input rating.  

Good Luck.  

Answer 3

I have a 75,000 BTU furnace for about 1300 sf of living space. I'm guessing it will heat up to 2000 sf. Good luck!