Are Electric Furnaces Energy Efficient?

December 18, 2020

When your Seattle, WA, home needs a new heating system, you’ll have several options to consider. An electric furnace is a good option in places that don’t get frigid weather during the winter months of the year. Seattle’s moderate climate makes an electric furnace a smart choice. Before you decide which electric furnace to buy, here’s what you need to know about their energy efficiency.

Understanding Electric Furnaces Versus Heat Pumps

Furnaces generate heat and use an air handler to blow the heated air into your home’s ducts. Heat pumps transfer heat. There are electric and gas furnaces. Electric furnaces use resistance wires that get hot when current flows through them. The forced-air system blows cool household air over those wires. The heated air then enters the ducts. Heat pumps use a chemical refrigerant to absorb heat from the outdoor air and pump it into your home. Furnaces generate heat, and heat pumps simply transfer heat.

How Electric Furnaces Work

An electric furnace produces heat from electrical current flowing through wires. When your thermostat triggers the start of a heating cycle, the electric ignition activates the heating elements. The furnace’s capacitor delivers an initial large load of stored current to those elements. As the current flows through the wires, they get hot. This is similar to how a toaster works. The blower fan pushes room-temperature air from your home’s intake vent across the heating element. The heated air then goes into the ducts and reaches the rest of your house. Once the thermostat registers that your home has reached the temperature you set on the thermostat, it stops the current from flowing. The fan blows the rest of the heated air into your ducts, then it turns off.

How Furnace Efficiency Is Measured

The American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) is an independent organization that calculates the energy efficiency of heating ventilation, air conditioning and refrigeration equipment. It rates furnaces using the annual fuel utilization efficiency (AFUE) rating. AFUE is expressed as a percentage. A furnace’s AFUE rating describes how much of the input energy is turned into output heat. For example, a furnace with 90% AFUE converts 90% of the input energy into heat. The other 10% is lost to the gases that go out of the flue.

Range of AFUE Ratings

Gas furnaces that are 30 years old may have an AFUE as low as 60%. New, energy-efficient gas furnaces can have an AFUE of up to 98.5%. An electric furnace is 100% efficient. That’s because virtually all of the input electricity is turned into heat. Electric furnaces don’t burn fuel and have no flue. This means that none of the input energy is lost to flue gases.

What Makes Electric Furnaces 100% Energy Efficient?

Electric furnaces convert almost all of the electricity they use into heat. The electricity that’s not used for generating heat is less than 1% of the total electrical input. That electricity is used to trigger the electric ignition and run the air handler’s fan.

Cost to Install and Operate an Electric Furnace

Electric furnaces cost less to buy and install. The furnace itself costs about one-third to one-half as much as a gas furnace. The installation costs are about 25% to 50% less than the installation costs of a gas furnace. Keep in mind that the operating cost of an electric furnace will usually be higher than that of a gas furnace. That’s because the cost of electricity is higher per BTU British thermal unit (BTU) compared to that of natural gas. Natural gas and electricity prices vary by supplier, season and availability, so it’s worth comparing prices and switching utility companies to lower the costs of heating your home.

Factors in Electric Furnace Energy Efficiency

Electric furnaces require a high voltage. That’s why it’s best to leave their installation to licensed and trained technicians. An improper installation could reduce the furnace’s efficiency at heating your home. Incorrect installation could also lead to a safety problem, such as drawing too much power from your home’s circuit breaker.

It’s also important to select an electric furnace with the right capacity. Our technicians make heating load calculations in order to determine what size of electric furnace your Seattle home needs. Those calculations take into account your home’s size, age, construction materials, amount of insulation, number and types of doors and windows and more. If too big of a furnace is installed, it will waste some of the energy. A furnace with insufficient capacity will have to cycle more frequently.

The startup of a heating cycle is what consumes the most electricity, so more frequent cycling would cause higher utility bills. Proper maintenance of the electric furnace also plays a big role in its energy efficiency. The most important part of routine electric furnace maintenance is changing the air filter. Replacing a dirty air filter in your electric furnace with a clean one will increase its energy efficiency and lower your heating costs by as much as 15%.

Additional Benefits of Electric Furnaces

In addition to the energy efficiency of electric furnaces, there are many other benefits to choosing this type of heating system for your Seattle home. Electric furnaces have lifespans of 20 to 30 years, which is about twice as long as the lifespan of gas furnaces. Since no fuel is burned in an electric furnace, their maintenance needs are minimal. There’s no soot or grime to clean out of an electric furnace. There’s no burner to clean or heat exchanger to inspect. This means fewer parts to malfunction.

You won’t have to deal with relighting a pilot light or worrying about carbon monoxide poisoning or a gas leak. The simple design of electric furnaces means there are fewer moving parts, no burner and no vents. This simplifies both upkeep and repairs. Electric furnaces tend to have fewer breakdowns, and their repairs are simpler and less expensive to perform. Fewer moving parts also means that electric furnaces don’t make as much noise during their heating cycles.

Energy Star Certification for Electric Furnaces

The Department of Energy and Environmental Protection Agency both operate the Energy Star certification process for a variety of residential and commercial heating, ventilation and air conditioning systems as well as other appliances. The residential furnace certification for electric furnaces requires that the system have at least a 95% AFUE. Residential furnaces are defined as those that use 225,000 BTUs or less of power. An electric furnace with the Energy Star certification will use 30% less electricity to heat your home compared to an electric furnace with the same BTU and heating capacity that doesn’t have this certification. Choosing an electric furnace with the Energy Star certification will give you peace of mind knowing that you’ve chosen an energy-efficient heating system for your home.

Brennan Heating & Air Conditioning is the trusted installer of energy-efficient electric furnaces in Seattle. We’re also ready to provide you with dependable heating and air conditioning maintenance, repair, replacement and installation services. Our electric, air duct cleaning and water heater services are designed with your comfort, well-being and budget in mind. To learn more about what makes electric furnaces energy-efficient, contact us at Brennan Heating & Air Conditioning.

Brennan Heating & Cooling icon