Electric Furnace Buying Guide
In the market for a new heating system? When you consider all of your options, here's what you need to know about electric furnaces.
If you’re planning on replacing your heating system or installing one for the first time, don’t rule out an electric furnace. Simple, long-lasting and cheaper upfront that other heating options, modern electric furnaces are descendants of the arc furnace, designed in 1879 by German-born British inventor Sir William Siemens. An estimated 10 to 15 percent of U.S. homes use an electric furnace as their primary heat source. Learn the details of electric furnaces and how they work, so you can make a fully informed decision about how to heat your home.
What Are Electric Furnaces and How Do They Work?
Electric furnaces are heating appliances consisting of an enclosed metal box containing an electric heating element and a blower fan. Like their oil and gas burning counterparts, electric furnaces are thermostatically controlled forced air units, switching on automatically when a thermostat detects the temperature of the building has dropped below the set point. With the heating element on, the internal blower fan also switches on automatically, blowing air over the heating element, and then distributing the newly warmed air through a network of ducts to where it’s needed in the building. When the set temperature is achieved, the heating element and blower fan shut off until they’re needed again.
Electric Furnace Parts and Features
Heat Elements: Thick bands or wires made of electrically resistant metal (usually a mixture of nickel and chromium). When electricity is fed into these, the electrical resistance produces heat.
Heat Relays: These regulate how much electricity is fed into the heating elements.
Plenum: A small air chamber area in the furnace that collects air and helps it circulate more efficiently.
Power Relay: This regulates how much electrical power the furnace draws.
Electrical Transformer: This lowers the incoming voltage (240 volts) to a voltage usable by the furnace’s control elements (often 24 volts)
Blower or Blower Fan: Internal motorized fan that blows cool air over the heating element, then forces that air into the ducts, heating the building according to the thermostat’s settings.
Return Air Ducts: These pull unheated air from the building into the furnace where the blower fan forces it over the heating element.
Filters: Household air is naturally full of airborne dust, fuzz and debris. Filters keep this unwanted matter from entering the furnace and being pushed through the ducts by the blower fan, and into other parts of the building. Filters should be replaced every few months (check your owner’s manual for the manufacturer’s specific recommendations) to keep your furnace running optimally.
Sequencers: Many electric furnaces have multiple heating elements. Sequencers control when each of them is turned on and off as heat is demanded, distributing the electrical load evenly.
Thermostat: Integrated with the furnace, the thermostat controls when the heating elements and blower fan come on and off, switching them on when heat is demanded, and off when the set temperature is reached.
Electric Furnace Considerations and Cost
- Electric furnace units range from $685 to $1,100. Installation costs range from $1,000 to $2,000, depending on the unit’s size and complexity.
- On balance, electric furnaces are about 300 percent more expensive to use than gas-burning units.
- Based on the current average cost of electricity in the U.S. of $0.13 per kilowatt hour, a typical electric furnace costs $32 per million BTUs to operate, compared to a cost of just $10 to $12 per million BTUs for a typical gas furnace.
- Electric furnaces are relatively compact compared to other types of furnace, and can be installed along with a cooling coil that provides air conditioning during warmer months.
- Some consider electric furnaces safer and more environmentally friendly than gas and oil burning furnaces, because they create no emissions and don’t involve combustion of any kind.
- On balance, electric furnaces are more expensive to operate than baseboard or wall heaters.
- Most budget electric furnaces last 15 to 20 years, while higher quality units often last 18 to 25 years.
Electric Furnace vs. Other Heating Options
Electric Furnace Pros:
- Upfront unit costs are as much as 50 percent less than gas and oil furnaces.
- Installation costs are lower due to electric furnaces not having to be vented, as gas an oil furnaces need to be.
- They don’t require outdoor fuel tanks like gas and oil furnaces. Oil furnace tanks often need replacement every 10 years or so, due to insurance policies and the risk of corrosion.
- Electric furnaces don’t produce carbon monoxide.
- Electric furnaces are comparatively easy to maintain, with only filters, fan motors and heating elements needing occasional to rare replacement.
- They’re more generally durable than heat pumps, and just as durable as gas furnaces.
Electric Furnace Cons:
- Higher usage costs than gas or oil furnaces due to electricity being more expensive than natural gas and oil.
- Electric furnaces aren’t usually recommended for full-time use in colder climates (mainly due to cost).