Gas vs electric furnace: the real annual cost gap

How the gas vs electric furnace math works

The calculator above runs the same arithmetic an HVAC engineer would. First, it figures out how much useful heat your home needs per year: peak heating load (BTU per hour at design temperature) times the annual equivalent full-load heating hours for your climate zone. A 45,000 BTU/hr home in zone 4 needs about 54 million BTU of heat per year (45,000 × 1,200 hours). That number is the same whether you burn gas or electric.

The difference is what you have to pay your utility to deliver that heat. Natural gas contains 100,000 BTU per therm, so a 96% AFUE furnace burns 54,000,000 / 100,000 / 0.96 = 563 therms per year. At $1.30 per therm, that costs $731 per year. An electric resistance furnace burns 54,000,000 / 3,412 / 0.98 = 16,142 kWh per year. At $0.16 per kWh, that costs $2,583 per year. The gap (about $1,850 in this example) is the gas-vs-electric operating cost spread for a typical zone-4 home.

Annual operating cost by climate zone

The cost gap scales directly with how many hours your furnace runs per year. Mild climates minimize the gap. Cold climates widen it. Using national-average rates ($1.30/therm gas, $0.16/kWh electric) and a 45,000 BTU/hr load:

These are national-average rates. Your actual numbers depend heavily on what you pay per therm and per kWh, which is why the calculator is here. The table is for orientation.

When electric furnace operating cost actually beats gas

Electric furnaces are the cheaper-to-run answer in three specific cases. Outside of these, natural gas wins almost everywhere it is available.

You pay over $1.20 per kWh for electricity and gas is below $0.12 per therm... oh wait. The rate combinations that flip the math are rare. The real cases where electric wins on operating cost:

• Heavily subsidized rural electric co-op rates below $0.08 per kWh. A few rural co-ops in the Pacific Northwest and parts of the Tennessee Valley still offer rates this low, and at the national-average gas price, electric can match or beat gas.
• No natural gas service available. If your only options are electric, propane, or oil, electric resistance often beats propane and oil on per-BTU cost. The comparison shifts from "gas vs electric" to "electric vs propane vs oil," and electric usually wins that fight in mild climates.
• Very mild climate plus low-use vacation home. If you heat to 50°F for freeze protection 4 months a year, the absolute dollars are small either way, and the simpler electric install is worth not having a gas line.

The calculator's "electric break-even rate" output tells you exactly what $/kWh your local gas price would need to drop to in order for electric to win. For most homes that number comes out below $0.06 per kWh, which is below any current U.S. residential rate.

Why an electric furnace is cheaper to put in

Electric furnaces are simpler equipment. No combustion chamber, no flue, no gas valve, no induced-draft motor, no condensate drain. The install reflects that simplicity.

• Electric furnace, 15-25 kW: $2,000 to $3,500 installed
• 80% AFUE gas furnace: $3,800 to $6,500 installed
• 96% AFUE gas furnace: $5,500 to $9,000 installed
• Adding new gas service to a home with no existing line: $1,500 to $5,000 extra

The install savings are $2,000 to $5,500 for electric over a like-for-like gas install. In a zone-4 home with the operating cost gap of $1,850 per year, gas pays back its install premium in 2 to 3 years and saves $20,000 to $35,000 over a 20-year equipment life. The install savings on electric are real but small compared to two decades of higher utility bills.

How a heat pump changes the gas vs electric math

An air-source heat pump delivers 2 to 4 BTU of heat per BTU of electricity it pulls, versus the 1-to-1 ratio of resistance heat. That changes the electric side of the math dramatically. A heat pump in zone 4 uses roughly 5,000 to 7,000 kWh per year for heating, not the 16,000 kWh an electric resistance furnace would use. At $0.16 per kWh that is $800 to $1,120 per year, which is competitive with gas in most of the country.

This is why the modern operating-cost comparison is rarely "gas vs electric resistance" anymore. It is "gas vs heat pump." Electric resistance furnaces still get installed in homes where heat pumps are not practical (rural off-grid, manufactured housing, mild climates with low heating needs), but for a typical home in zones 1 through 5 the live decision is between gas and a heat pump. Run that one through the heat pump vs gas furnace calculator if it is in scope for your home.

Comfort and reliability differences

Operating cost is the headline number, but two other practical differences matter day to day.

Supply air temperature. A gas furnace pushes 130°F to 145°F air through the supply registers. An electric resistance furnace pushes about 100°F to 115°F. The lower supply temperature on electric feels less aggressive when it hits your skin from a register, but it also means longer run cycles to heat the same room because each unit of air carries less heat. In a well-insulated house this is invisible. In a drafty older house with marginal ductwork, gas often feels noticeably warmer.

Reliability and repair. Electric furnaces have very few moving parts: blower motor, heating elements, control board. When they fail, the failure is usually a burned-out element ($200-$500 to replace) or a bad control board ($300-$700). Lifespan typically runs 20 to 30 years. Gas furnaces have many more failure points: igniter, flame sensor, gas valve, induced-draft motor, heat exchanger, control board. Most repairs are $200 to $800 but a cracked heat exchanger condemns the entire furnace. Lifespan is typically 18 to 25 years.

Fuel inflation: is gas going to stay cheap?

The 20-year lifetime savings number in the calculator assumes constant fuel rates. Real rates inflate. Natural gas residential prices have inflated 2 to 4 percent per year on average over the past two decades according to EIA data, with major spikes during supply shocks (winter 2021, 2022). Electricity prices have inflated 3 to 5 percent per year on the same timeframe, with bigger regional variation tied to local generation mix.

Both fuels are getting more expensive, but electricity has been inflating slightly faster. The relative position has not shifted enough to flip the gas-wins-in-cold-climates story, but the long-run trajectory does favor whichever fuel is decarbonizing faster (mostly electricity, as more renewables come on grid). For a 20-year buying decision today, the lifetime cost gap is real and worth weighting heavily. For a 5-year decision, current rates dominate.

The bottom line on gas vs electric heating cost

For a home in any U.S. climate zone with natural gas service available, the gas furnace is almost always the cheaper choice over its lifetime, often by $20,000 to $40,000 in cold climates. The install premium pays back in 2 to 4 years, and the rest of the equipment life is profit on the operating-cost side.

Electric resistance furnaces make sense in three situations: no gas service available, very mild climate where total heating cost is small either way, or as a starter system in a home you plan to electrify with a heat pump within 5 years. Outside of those cases, if gas is on the table, gas is the answer. The calculator above will tell you in seconds what your actual numbers say. The break-even electric rate output is particularly useful if you live somewhere with unusually cheap electricity or unusually expensive gas.