Electric vs Gas Furnace: Which Costs Less to Run, and What Each Needs When Power Fails
Choosing between an electric and gas furnace affects more than your winter comfort. It can change your monthly utility bills, installation requirements, and options when the power goes out. Gas is usually cheaper to run at national average energy prices, but your local rates and furnace efficiency matter. There is another detail homeowners sometimes overlook: a gas furnace still needs electricity for its controls and blowers, while an electric furnace requires substantially more power to produce heat. Here is how the two compare cost, safety, comfort, and backup power.
Is a Gas Furnace Cheaper Than Electric? Working It Out per Million Btu
Gas is sold by the therm or thousand cubic feet, while electricity is billed by the kilowatt-hour (kWh). Comparing these bills directly can be misleading. A fairer approach is to calculate the cost of delivering one million British thermal units (Btu) of heat into your home. Using the U.S. Energy Information Administration's (EIA) national average prices for the first quarter of 2026, natural gas generally comes out ahead.
The inputs (all EIA, all labeled)
This comparison uses typical U.S. residential energy prices, energy conversion rates, and furnace efficiency ranges to estimate the cost of electric versus gas heating. These figures help show how energy prices and furnace efficiency affect the cost of keeping your home warm.
Electricity: 17.83 cents per kWh.
Natural gas: $14.77 per thousand cubic feet (Mcf), equivalent to approximately $1.42 per therm.
Energy conversion: 1 kWh equals approximately 3,412 Btu, while 1 Mcf of natural gas contains about 1.037 million Btu.
Furnace efficiency: Electric furnaces typically achieve 95%–100% annual fuel utilization efficiency (AFUE). Gas furnaces range from about 80% for older mid-efficiency models to approximately 98.5% for high-efficiency models.
Cost per million Btu of delivered heat
The table below compares the estimated cost of delivering one million Btu of heat using electric and gas furnaces, based on EIA national average energy prices for Q1 2026. It accounts for fuel prices and furnace efficiency to show which option typically costs less to operate.
Calculation | Electric furnace | Gas furnace |
Energy price | $0.1783/kWh | $14.77/Mcf |
Cost per million Btu of fuel | About $52.26 | About $14.24 |
After furnace efficiency | About $52–$55 | About $15–$17.80 |
Typical fuel-cost result | Higher | Lower |
These figures are estimates, not guaranteed household bills, as they exclude fixed monthly charges, gas furnace electricity use, duct losses, and utility rate tiers. Actual costs depend on your equipment and local fuel prices, so divide your total bill by kWh or therms consumed to find your unit rate. Understanding how energy measurements compare through this Btu-to-kWh conversion can help you make a more accurate calculation. Electric resistance heating can be expensive in areas with high electricity rates, so if you prefer an all-electric system, consider a heat pump, which the DOE says can reduce electricity use for heating by up to 75% compared with electric resistance heating.
What Each Furnace Needs When the Grid Goes Down
A gas furnace burns natural gas to produce heat, but it still relies on electricity for its ignition system, control board, inducer motor, and blower. When grid power fails, the furnace generally stops working unless a compatible backup source supplies electricity. An electric furnace has a different challenge. Its heating elements can draw several kilowatts, making backup power more demanding.
Gas furnace: a modest 120V load
Many residential gas furnaces use a 115V or 120V electrical supply to power their controls and blower, while natural gas provides the heat. For example, Carrier's 59SC5B specifications list maximum input currents of 5.1 to 12.6 amps, depending on the model. A 115V unit drawing 7.1 amps uses approximately 817 volt-amps, so a 5,000Wh battery with 85% usable energy could theoretically support that load for about 5.2 hours. Actual runtime depends on furnace cycling, startup demand, conversion losses, and other connected devices, so check the furnace's electrical requirements and confirm that gas remains available before planning backup power.
Electric furnace: often bigger than a home battery's output
Electric furnaces typically use 240V circuits and require substantially more power than gas furnaces. A 5kW heating element draws about 5,000 watts, while a nominal 10kW heating kit may draw around 9.2kW, depending on its specifications. Before choosing a backup system, check the furnace's rated demand and review how electric furnace wattage and heating costs affect your power needs, because a battery rated for 7,200W cannot continuously support a load that exceeds that output. Larger systems may also use multiple circuits or staged heating elements, which must be evaluated for compatibility.
Backup options for the two furnace types
A properly configured battery system may help keep compatible heating equipment running during an outage. The key is matching the equipment's voltage, output, capacity, and connection method.
EcoFlow TITAN 5000 Classic — for compatible 120V gas furnace circuits
The EcoFlow TITAN 5000 Classic provides 4,000W of rated AC output at 120V and 5kWh of battery capacity per unit. It may support a compatible gas furnace's electrical circuit when the startup and running loads fall within its limits. It cannot power a 240V electric furnace. Capacity can be expanded to 30kWh using compatible additional batteries. The 120V Smart Home Panel 10 option can switch selected circuits, with installation by a licensed electrician.
EcoFlow TITAN 5000 — for compatible 120V and 240V loads
The EcoFlow TITAN 5000 provides 7,200W of rated AC output with split-phase 120V/240V power and 5kWh of battery capacity per unit. It may support selected electric heating loads if an electrician confirms that the furnace's total demand and startup requirements are within the system's limits. Many whole-house electric furnaces exceed 7,200W, so load shedding or a different backup arrangement may be necessary. Compatible additional batteries can expand capacity to 30kWh.
The EcoFlow TITAN 5000 Classic can support a compatible 120V gas furnace circuit if its starting and running loads stay within the 4,000W output limit, while the EcoFlow TITAN 5000 may support selected 240V heating circuits if the load fits within 7,200W. Since electric furnaces often require split-phase power, understanding how a home battery with 240V power output works can help you assess compatibility. Both systems require matching Smart Home Panel 10 and licensed electrician installation, and neither guarantees whole-home heating throughout the night.
Installation, Venting, and Safety Side by Side
The main installation difference is straightforward: electric furnaces need substantial electrical capacity, while gas furnaces require both electricity and a gas supply. Gas systems also need appropriate combustion venting.
Factor | Gas Furnace | Electric Furnace |
Fuel connection | Natural gas line | Electrical supply |
Electrical needs | Usually 120V for controls and blower | Often 240V, with substantial heating loads |
Venting | Required for combustion gases | No combustion vent |
Typical AFUE range | About 80%–98.5% | About 95%–100% |
Carbon monoxide | Combustion risk requires precautions | No on-site combustion |
Outage challenge | Needs backup for controls and blower | Needs backup for the full heating load |
Safety requirements to remember
If you choose gas heating, schedule professional maintenance at least annually and install battery-operated carbon monoxide (CO) detectors, as recommended by the CDC. Test alarms regularly, keep combustible materials at least three feet from heating equipment, and never use a portable generator, gas grill, or outdoor fuel-burning heater indoors. As you weigh the pros and cons of natural gas, consider fuel availability, emissions, infrastructure, and household safety before making your decision.
Comfort, Climate, and Which Furnace Fits Your House
Both furnace types can distribute warm air through ductwork, so either can provide comfortable heating when properly sized and maintained. Your climate, local energy prices, insulation, and access to natural gas will usually matter more than the fuel type alone.
Climate: Colder regions require more heating hours, increasing seasonal energy use and making the difference in fuel costs more significant.
Natural gas availability: Homes without access to a natural gas supply may need an electric furnace or heat pump.
Duct losses: Both furnace types can lose heat through ducts running in unheated spaces, reducing overall efficiency.
ENERGY STAR certification: Certified gas furnaces can be up to 16% more efficient than baseline models in the U.S. South and 18% in the North. Certified models also use more efficient blower motors.
Heat pump alternative: The U.S. Department of Energy recommends considering heat pumps because they can provide efficient heating and cooling. They can also use substantially less electricity than electric resistance heating.
Your situation | Usually points to |
Natural gas is already available and winters are cold | A high-AFUE gas furnace |
No natural gas service and winters are mild | An electric furnace or, preferably, a heat pump |
Planning battery backup during power outages | A gas furnace, because its electrical load is typically much smaller |
Want to avoid combustion inside the house | An electric furnace or heat pump |
Want one system for heating and cooling | A heat pump |
Before choosing a furnace or planning battery backup, compare electric furnace wattage and cost figures to understand the equipment's power requirements and potential operating costs. Your final choice should account for installation costs, local energy rates, heating needs, and the electrical capacity available in your home.
Conclusion
Gas furnaces typically deliver heat at a lower fuel cost than electric furnaces, based on EIA's early 2026 national averages. Electric furnaces avoid combustion but generally cost more to operate and require greater backup power. To compare costs accurately, calculate the cost per Btu using your utility bills and ask your HVAC contractor to confirm your furnace's electrical requirements. For outage backup, compare the EcoFlow TITAN 5000 Classic for compatible 120V gas furnace circuits and the EcoFlow TITAN 5000 for approved 240V heating loads.
FAQs
Is a gas furnace cheaper than electric?
Usually, yes, at the national average fuel prices used in this example. A gas furnace can deliver heat at a much lower cost per million Btu, although local gas and electricity rates affect the final result.
Does a gas furnace work during a power outage?
Generally, no. Its ignition system, controls, and blower need electricity. A compatible backup power source may keep it operating if the gas supply remains available.
How much electricity does a gas furnace use?
It depends on the model. As one example, the Carrier's 59SC5B range lists maximum input currents of 5.1–12.6 amps at 115V. Check your furnace's rating plate for its actual requirements.
Are electric furnaces more efficient than gas furnaces?
Electric furnaces typically have higher AFUE ratings because they convert nearly all their incoming electricity into heat at the point of use. However, higher efficiency does not necessarily mean lower operating costs when electricity is more expensive per unit of energy.
Can a home battery run an electric furnace?
Sometimes, if the furnace's voltage, startup demand, and running wattage fit the battery system's limits. Many whole-house electric furnaces draw more power than a 7,200W system can supply, so professional load calculations are essential.
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