How Do I Size an Electric Furnace?

Step 1: find your heating output

Start with your home's total heated square footage and multiply by a climate factor. Colder climates need more BTU per square foot. This gives your approximate required heating capacity.

Step 2: match a kW heating element

Electric furnaces produce heat with a kW element. Pick the element whose BTU output most closely matches your requirement from Step 1.

Most electric furnaces come in 7,000 to 10,000 BTU steps, so you only need to get close. If the furnace you choose is more than 10% below your requirement, size up to the next element. You can browse electric furnaces and their element options to match your number.

What if I need more than 68,000 BTU?

A single electric furnace tops out near 20 kW (68,000 BTU). If your home needs more, the options are two electric furnaces on separate duct systems, or a gas furnace, which reaches higher outputs from one unit. Keep in mind that larger elements draw more power, so confirm your electrical service can support the size you pick.