How to Choose a Furnace
Choosing a furnace can be confusing. If you know the square-footage of your home, here's how to choose the right size:
Furnace size is measured using the amount of heat it produces, and amount of heat is expressed in in BTU, which is short for British Thermal Unit.
The size of the furnace depends on the climate you live in and the square footage of your home. For the climate in Canada, to calculate the furnace size for your home, you would need about 31 BTU per square footage. So, if your home is, for example 2000 square-feet, we need a 62,000 Btu furnace :
2,000 square feet X 31 BTU per square feet = 62,000 BTU (output required)
However, no furnace is 100% efficient, thus, we need to take that into account. For example, 62,000 BTU furnace with an efficiency of 85% will produce only 53,000 BTU heat, therefore we need a 80,000 BTU furnace and an efficiency rating of 85% or higher to heat a home with 2000 square footage:
62,000/0.85 = 80,000 BTU's