Electric Baseboard Heater Sizing

As a baseline for rooms with modern construction and insulation and 8 ft ceilings, use 10 watts per square ft. 

Most electric baseboards are 250 watts per linear ft.

So, for example, if you have a room that is 10′ x 10′ with 8′ ceilings, you will need 1000 watts.

10 x 10 = 100 sq. ft.

100 sq. ft. x 10 watts per sq. ft. = 1000 watts.

1000 watts/250 watts per foot = 4 ft.

So, you would need a 4 ft. baseboard heater.

*For rooms with a 10 ft. ceiling multiply the wattage x 25%

*For rooms with a 12 ft. ceiling multiply the wattage x 50%

*For older homes with little to no insulation, use 12.5 watts per sq. ft.

*For homes that are ultra-insulated, use 8.5 watts per sq. ft.