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How many watts does an electric furnace use?

Heating and cooling bills are some of the biggest expenses of owning or renting property. For that reason, it’s important to know just how much electricity an electric furnace uses when you’re looking at your whole home’s energy usage.

Key takeaways about powering an electric furnace

  1. On average, electric furnaces use 10,000 to 50,000 watts (10 to 50 kilowatts) of electricity.

  2. Electric furnaces usually use about 26 kilowatt-hours of electricity per day, and 182 kilowatt-hours of electricity per week.

  3. It costs an average of $37.42 to run an electric furnace for a month, and $449 to run for a year

  4. The best way to save on electricity is to install solar panels. Start comparing your options on the EnergySage Marketplace today.

In this article

How much electricity does an electric furnace use?

Generally, electric furnaces use 10,000 to 50,000 watts (W) of electricity, depending on the model. On average, it’s safe to assume that electric furnaces in standard residential homes use about 20,000 W. Most electric furnaces use between 60 and 80 amps, and connect to a 220 volt breaker.

Importantly, furnaces generally have a much lower “running” wattage than their stated wattage – this is because they cycle on and off throughout the day. As a general rule of thumb, furnaces cycle on and off 2-3 times each hour for about 15-20 minutes at a time, which is about 35 minutes in every hour. So, a 20,000 W electric furnace actually will use about 13,000 W each hour.

There’s one more important caveat to remember with electric furnaces: they just don’t make much financial sense in many parts of the U.S. In fact, the Southeast and Southwest regions are the only areas of the country where electric furnaces are somewhat common, and those areas might only need a few hours of heating per day. As such, we’ll use an average of two hours of electric furnace heating needed per day in our calculations.

How much you run your electric furnace has the biggest impact on how much electricity it uses over time:

How much electricity do electric furnaces use? Electric furnace wattageActual energy usageLength of time poweredkWh of electricity used 20,000 W13,000 W1 hour13 kWh 20,000 W13,000 W1 day26 kWh* 20,000 W13,000 W1 week182 kWh* 20,000 W13,000 W1 month789 kWh* 20,000 W13,000 W1 year3,163 kWh**

*Assuming two hours of operation per day **Assuming two hours of operation per day, and four months per year

Different wattage electric furnaces use different amounts of electricity over the course of a year. Assuming again that the average electric furnace is run for two hours per day for four months of the year, here’s how much electricity you’ll use over the course of a full calendar year:

How many watts do different electric furnaces use in a year? Electric furnace wattageActual energy usageYearly kWh of electricity 10,000 W6,500 W1,582 kWh 15,000 W9,750 W2,373 kWh 20,000 W13,000 W3,163 kWh 25,000 W16,250 W3,954 kWh 30,000 W19,500 W4,745 kWh

We’ll mostly be referring to the electricity used by electric furnaces in terms of kWh in this article. The reason is simple: your electric bill is measured in kWh, and you get charged based on the kWh of electricity you use per month!

Watts, amps, voltage, and more: what do they mean?

There are a lot of terms you can use to describe how electricity flows and is used by appliances. We’ve already mentioned most of them – here are a few definitions to keep things straight:

  1. Volts (V): volts (short for voltage) are measures of electrical pressure differences. Put simply, voltage is the speed of electricity passing through a circuit.

  2. Amps (A): amps (short for amperes) are a measure of electrical current. Put simply, amps are the amount of electrons (which make up electricity) flowing through a circuit.

  3. Watts (W) and kilowatts (kW): multiplying volts x amps gets you watts (or wattage). Put simply, watts are the rate of electricity consumption. A kilowatt is just 1,000 watts.

  4. Kilowatt-hours (kWh): lastly, kilowatt-hours are how your electric bill measures your energy usage. Simply put, kilowatt-hours are electricity consumption over time.

You can think of all of these terms like water flowing through a pipe. Voltage is the water pressure, amps are the amount of water flowing past any point, and wattage is the overall rate of water flow through the pipe.

How much does it cost to power an electric furnace?

When you get your monthly electric bill, you only get to see the total amount you’re charged, not how much each appliance contributes to your final bill. Based on an average wattage of 20,000 W for electric furnaces (amounting to 3,163 kWh/year if you use your electric furnace like an average household would) and using state average electricity rates, here’s how the cost to run an electric furnace pans out over the course of a month (on average) and a year:

Monthly and yearly costs to run an electric furnace by state StateAverage electricity rateAverage cost per monthCost per year California22.00 ¢ / kWh$58.00$696 New York20.59 ¢ / kWh$54.25$651 Texas12.56 ¢ / kWh$33.08$397 Massachusetts22.59 ¢ / kWh$59.58$715 Florida12.21 ¢ / kWh$32.17$386 Virginia12.58 ¢ / kWh$33.17$398 New Jersey16.20 ¢ / kWh$42.67$512 Maryland14.48 ¢ / kWh$38.17$458 Washington10.38 ¢ / kWh$27.33$328 US Average14.19 ¢ / kWh$37.42$449

Importantly, most households that use electric furnaces only need to use them for about four months out of the year on average. The monthly cost numbers in the table above simply reflect the yearly estimated cost divided by 12 months – but in reality, you can divide your yearly cost by four for a more accurate picture of what one month’s electric bill will look like when you’re running an electric furnace. For example, homeowners in California might expect to spend $174 per month for only four months on heating ($696 / 4 months).

Looking to offset your electric bills (and the energy these appliances use) with solar? When you sign up (for free!) on the EnergySage Marketplace, you can compare solar quotes from high-quality, local solar installers. Make sure to keep in mind your current and future electricity usage, and talk about how that could change with your installer for the most accurate quotes.

See what electricity costs near you

The more expensive your electricity is, the more you can save by taking the actions above. Curious how much electricity costs near you? Click on your state to learn more:

Frequently asked questions about powering an electric furnace

What’s the best time to run an electric furnace?

If you’re on a time-of-use (TOU) rate plan, you are charged different amounts for electricity throughout the day. In general, it’s cheaper to use an electric furnace during “off-peak” hours, which are usually overnight. For an electric furnace, you may have less of an option, as you’ll just need to run it when it’s colder.

What size battery do you need to back up an electric furnace?

Most lithium-ion batteries like the Tesla Powerwall or Generac PWRcell have a power rating of 4 to 5 kW or higher, and 10+ kWh of usable capacity. Electric furnaces use about 20,000 W (1.5 kW) of power at any one time, meaning you’ll need several batteries worth of power to keep an electric furnace running for any extended period of time.

How many solar panels does it take to power an electric furnace?

Average electric furnaces use 20,000 W of electricity to stay powered. On average, solar panels are rated at around 350 W, meaning you’ll need a whopping 50-60 solar panels to provide enough power to an electric furnace.

What are ENERGY STAR appliances?

ENERGY STAR is a U.S. government-backed system that certifies how energy efficient appliances are. If an appliance is better than the average appliance in its category by a certain amount, it is labeled as “ENERGY STAR certified”. ENERGY STAR appliances cost less money to run, given that they are more efficient with the electricity they use.

How much money can solar panels save you?

Solar savings vary widely, and your unique savings depends on factors like electricity usage, your location, electric rates and plans, and more. In general, most homeowners can expect to save somewhere between $10,000 and $30,000 over the lifetime of a solar panel system. On average, it takes between 7 and 8 years for most homeowners who shop for solar on EnergySage to get their solar panels to pay for themselves.

Going solar is one of the most effective ways to reduce or eliminate your electric bill, and you should make sure you are getting several quotes from reputable installers before you decide to move forward. Visit the EnergySage Marketplace to get solar quotes from installers in your area and begin comparing options.


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