Things You'll Need

Instructions

1

Measure the size of your home’s rooms to determine the square footage you intend to heat with the boiler. To get the measurement for square footage, you have to multiply every room’s width by its length. Add all the square footage measurements together to get the total. For example, if you have a home with four rooms all measuring 9 by 10 feet, the product for each of those rooms would be 90 square feet. The total of all of those rooms would be 90 multiplied by 4, or 360 square feet total.
2

Multiply the total square footage of your home by the amount of heat you want from the electric boiler. If you only want supplemental heat, multiply by 6. For a 1,500-square-foot home, you would need a 9,000-watt boiler.
3

Multiply by 10 to 15 to get the number of watts needed to heat your whole home. For a 1,500-square-foot house, you would need a boiler with between 15,000 and 22,500 watts.