Each climate zone has a recommended heating factor which is the suggested number of btus per square foot.
60000 btu furnace heats how many square feet.
And in cold climates multiply the square foot number by 30 40.
For example if a furnace is rated at 100 000 btus and is 80 efficient then the heat output will be 80 000 btus 100 000 x 8.
Its heating factor is 50 to 60 btus.
You might want to plan to invest in upgrading the insulation putting in new windows and weatherstripping around the doors.
Your heating bills will probably be sky high though.
1900 square feet x 40 heating factor from the chart above 76 000 btu required to heat your home.
A heating degree day calculation using the month.
One therm is equal to 100 000 btu or 0 10 mmbtu while 100 cubic feet of natural gas equals 103 700 btu or 1 037 therms.
Furnaces are rated on their btus of energy consumption not their btus of energy output.
A more efficient furnace will output more btus of heat than a less efficient furnace with the same btu rating.
Btu charts furnace output and air conditioner size for a bungalow bungalow area sq ft 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 readmore.
A mid sized home of 2 000 square feet would need approximately 50 000 to 60 000 btu to heat it properly.
A furnace putting out 60 000 btu s per hour will probably handle the heating load even though your house is most likely uninsulated and in a very cold climate.
At 40 to 45 btus per square foot you d need a 100 000 to 112 500 btu furnace to heat your 2 500 square foot home.
If you live in either of these cities you will need a heater that produces 45 to 50 btus per square foot.
For example chicago and new york are both in zone 4 which has a heating factor of 45 to 50.
Therefore the price per 100 cubic feet divided by 1 037 is equal to the price per therm.
For this example using an 80 efficient furnace the 1900 square foot home above would require a 90 000 btu input furnace that produces 72 000 btu s of heating which is close enough to the 76 000 btu s required using the climate heating.