1kW is 3,412.13 BTU/hr
A BTU is about 1055 joules. A kilowatt is 1000 joules/second, so it is 3,600,000 joules/hour. Dividing that by 1055 joules gives you the equivalent of about 3400 BTU/hour.
Many factors figure in other than square footage. Such as the height of the ceiling and number of windows. But, for most houses, 20 to 22 btu per square foot will do. 40,000 to 45,000 btu should do.
Divide the dollars per kWh by 3,412.14163
You need to look at a steam table first then Multiply lbs/hr steam x latent heat of evaporation in BTU/lb @ the operating pressure.
114,000 BTU/gallon
2500 btu per cubic foot of vapor.
For regular gasoline, 125,000 BTU per US gallon
12,000 btu = 0ne ton
One BTU per second is 1.434 hp
65,000 BTU per hour equates to 19.05 kW
50
Propane = 91,600 btu per gallon
20 btu per square foot
1 ton of heating is equal to 12,000 BTU per hour.
1 kW is equal to 3412 BTU per hour.
1kW is 3,412.13 BTU/hr