Air Conditioner and Furnace Sizing

WHAT SIZE AIR CONDITIONER OR FURNACE DOES MY HOUSE REQUIRE?

Many factors are involved when determining what size of an air conditioner or furnace would have the required power output to cool or heat your home. These factors include the extent of exposure to the sun and the outside air, the thickness and type of outside wall insulation, the size, type and number of windows and outside doors, the ceiling height, etc.

Generally speaking, however, if you live in Southern Ontario, you may use the following charts to estimate the correct size of the heating or cooling product that you may need for your home.

Keep in mind that the following furnace output power estimates are aside from the furnace’s nominal power ratings. For example, a 95% rated efficiency furance with a power rating of 80,000 BTU/hr has a power output of 0.95 x 80,000 BTU/hr = 76,000 BTU/hr.

Furnace Output and Air Conditioner size for a Bungalow

Bungalow Area [square feet] *
Furance Output [BTU/hr] Air Conditioner size [ton]
Built after year 1980 Built before year 1980 Built after year 1980 Built before year 1980
up to 1200 sq ft
40,000 BTU/hr
50,000 BTU/hr
1.5 ton
up to 2 ton
1200 to 1500 sq ft
50,000 BTU/hr
55,000 BTU/hr
2 ton
2 ton
1500 to 1800 sq ft
55,000 BTU/hr
60,000 BTU/hr
2 ton
up to 2.5 ton
1800 to 2500 sq ft
65,000 BTU/hr
70,000 BTU/hr
up to 2.5 ton
2.5 to 3 ton
2500 to 3500 sq ft
80,000 to 90,000 BTU/hr
90,000 to 100,000 BTU/hr
3 to 3.5 ton
3.5 to 4 ton
* The above square footages do not include the area of the basement.

Furnace and Air Conditioner size for a semi-detached 2-storey home

Semi-detached House square footage *
Furnace Output [BTU/hr]
Air Conditioner size [ton]
Built after year 1980
Built before year 1980
Built after year 1980
Built before year 1980
up to 1500 sq ft
40,000 BTU/hr
50,000 BTU/hr
1.5 ton
up to 2 ton
1500 to 1800 sq ft
50,000 BTU/hr
55,000 BTU/hr
up to 2 ton
2 ton
1800 to 2200 sq ft
55,000 BTU/hr
60,000 BTU/hr
2 ton
up to 2.5 ton
2200 to 3000 sq ft
60,000 BTU/hr
70,000 BTU/hr
2.5 ton
2.5 to 3 ton
*The above square footages do not include the area of the basement.

Furnace and Air Conditioner size for a detached 2-storey home

House square footage *
Furnace Output [BTU/hr]
Air Conditioner size [ton]
Built after year 1980
Built before year 1980
Built after year 1980
Built before year 1980
up to 1300 sq ft
40,000 BTU/hr
50,000 BTU/hr
1.5 ton
up to 2 ton
1300 to 1700 sq ft
45,000 BTU/hr
up to 55,000 BTU/hr
1.5 ton
2 ton
1700 to 2500 sq ft
55,000 BTU/hr
up to 65,000 BTU/hr
2 to 2.5 ton
2.5 ton
2500 to 3500 sq ft
up to 65,000 BTU/hr
up to 80,000 BTU/hr
2.5 to 3 ton
3 to 3.5 ton
3500 to 4500 sq ft
up to 80,000 BTU/hr
up to 100,000 BTU/hr
3.5 to 4 ton
4 to 5 ton
*The above square footages do not include the area of the basement