Electric furnace
How much electricity does an electric furnace use?
10,000–20,000 W · COP 1.0 · $200–$500 per month
Electric resistance heating is simple, reliable and cheap to install — and by far the most expensive to run. There is no efficiency trick available: 10 kW in always produces 10 kW of heat, no matter the brand or controls.
Rough monthly cost
A 15 kW furnace running an equivalent of four hours a day in winter is 60 kWh a day — about 1,800 kWh a month, or roughly $300 at 16.5¢/kWh. In a cold climate with a poorly insulated house it can exceed $500.
Why the heat pump comparison dominates
- Electric furnace: COP 1.0
- Air-source heat pump: COP 2.5–4.0 average across a season
- Result: the same heat for 25–40% of the electricity
For a $300/month furnace, a heat pump running at an average COP of 3 would be about $100/month. The saving usually pays for the installation within five to eight years, faster with incentives.
Cheaper intermediate steps
If replacement is not on the table, insulation and air sealing reduce the load the furnace has to meet, and a programmable thermostat with setbacks while away or asleep can cut 8–15% with no equipment change at all.
Frequently asked questions
How many watts does a electric furnace use?
10,000–20,000 W. The figure on the rating label is the maximum draw; actual use varies with settings, age and usage pattern.
How much does it cost to run a electric furnace per month?
With the defaults above it comes to the monthly figure shown in the calculator. At 16.5¢/kWh — the US residential average — that is a realistic middle estimate. Your own bill may be 30% lower or higher depending on state.
Is it cheaper to run a electric furnace at night?
Only if your utility offers a time-of-use plan and you avoid the 4pm–9pm peak window. On a flat-rate plan, the time of day makes no difference to the total.
Does the calculator account for real-world duty cycles?
Not automatically — you enter the effective hours yourself. For compressing appliances like refrigerators and AC units, enter the running watts and roughly the proportion of time the compressor is on, which is usually 30–50%.
Will a newer electric furnace actually save money?
Compare the kWh figure in the calculator against an Energy Star model's stated annual use. If the difference is a few hundred kWh a year, the payback on a replacement is usually long; if it is over 500 kWh, it is worth pricing out.