Electric vs Gas Heating Cost
Put in what your bill actually charges per kWh and per therm, how efficient the furnace is, and the heat pump COP if you have one. Every option becomes a single number: dollars for one million BTU of delivered heat, the only fair way to compare fuels sold in different units.
Utility blogs compare sticker tariffs and call it done. This page divides by efficiency - an 80% furnace pays 25% more per heat unit than its nameplate, a COP 3 heat pump turns one purchased kWh into three of heat - and says out loud that delivery charges, not the fuel, often decide the verdict.
How to use
- Use all-in rates from your latest bill, not the advertised generation rate.
- Set furnace efficiency: 80% for older units, 95% for modern condensing.
- Keep the COP at 3 unless you know your unit; deep cold pushes it lower.
Frequently asked questions
What is cheaper per unit of heat, electric or gas?
At US averages - 17 cents per kWh against $1.60 per therm - resistance electric costs about $50 per million BTU and gas about $17, so gas wins by roughly 3x. A heat pump at COP 3 brings electric down near $17 and usually takes the lead.
Why compare heating in dollars per million BTU?
Electricity is sold in kWh, gas in therms, propane in gallons - raw prices cannot be ranked against each other. One million BTU is the same heat in every fuel, so dividing each price by its efficiency collapses the comparison into one number.
Does furnace efficiency really change the math?
Yes: every dollar buys only 80-95 cents of heat depending on the unit, so an old furnace on a cheap tariff can cost more per heat than a modern one on a pricier tariff. The calculator prices this instead of trusting the nameplate.
Is a heat pump worth it over a gas furnace?
On running cost the pump wins whenever its COP beats your normalized electric-to-gas price ratio - with COP 3 and typical US prices that is roughly break-even to cheaper, and it pulls ahead every time gas spikes, while also replacing the AC. Upfront install cost is the honest trade.