Compare what it costs to heat your home with natural gas, propane, heating oil, electric resistance heat, a heat pump or wood pellets. Start from your yearly heat need, your home size and climate, or last year's fuel use, then enter local fuel prices and system efficiencies.
Last updated:
Heat needed per year
Set heat need from
MMBtu
1 MMBtu = 1,000,000 BTU = 10 therms = 293 kWh.
sq ft
%
AFUE for furnaces/boilers; for a heat pump use COP × 100 (e.g. 280).
Choose how to set your heat need. Using last year's fuel use from your bills gives the most realistic result.
Enter the numbers for that method: MMBtu per year, your floor area and climate, or the fuel you burned and your current system's efficiency.
Enter local prices for each fuel. Use the full delivered price including delivery and taxes.
Adjust efficiencies to match the equipment you have or are considering.
Compare the yearly cost of each option and the savings against your current fuel.
How heating costs are compared
Every fuel is converted to the cost of the heat it actually delivers into your home:
Yearly cost = heat needed ÷ (energy per unit × efficiency) × price per unit
Fuel
Energy per unit
Typical efficiency
Example price
Cost per MMBtu delivered
Natural gas
100,000 BTU / therm
80%–98% AFUE
$1.50 / therm
$15.79 at 95%
Propane
91,500 BTU / gal
80%–98% AFUE
$2.80 / gal
$32.21 at 95%
Heating oil
138,500 BTU / gal
80%–90% AFUE
$3.80 / gal
$32.28 at 85%
Electric resistance
3,412 BTU / kWh
100%
$0.17 / kWh
$49.82
Heat pump
3,412 BTU / kWh
COP 2–4.5
$0.17 / kWh
$17.79 at COP 2.8
Wood pellets
16.4 MMBtu / ton
70%–85%
$350 / ton
$26.68 at 80%
Natural gas billed in CCF (100 cubic feet) contains about 103,700 BTU per CCF, slightly more than a therm. Prices are examples only; use your own local delivered prices.
Estimating the yearly heat need
When you choose home size & climate, the heat need is estimated with the degree-day method:
BTU per year = floor area × heat-loss factor × 24 × heating degree days
The heat-loss factor (BTU per hour per °F per square foot) depends on insulation and air-tightness. The calculator uses 0.35 for poorly insulated homes, 0.22 average, 0.15 for modern code-built and 0.09 for high-performance homes. These are rough figures: the last year's fuel use method is more accurate because it reflects your real house and habits. For a room-by-room design load, use the heat loss calculator.
Example: a 2,000 sq ft average home in a 5,000 HDD climate needs about 2,000 × 0.22 × 24 × 5,000 = 52.8 MMBtu a year. With gas at $1.50/therm in a 95% furnace, that costs about $834 a year; with a COP 2.8 heat pump at $0.17/kWh, about $940.
Frequently asked questions
How do I compare heating fuel costs?
Convert every fuel to the cost of one million BTU of delivered heat: price per unit ÷ (BTU per unit × efficiency) × 1,000,000. Natural gas has 100,000 BTU per therm, propane about 91,500 BTU per gallon, heating oil about 138,500 BTU per gallon, electricity 3,412 BTU per kWh and wood pellets about 16.4 million BTU per ton. The lowest cost per delivered million BTU is the cheapest way to heat.
Is a heat pump cheaper than gas?
It depends on the price ratio of electricity to gas and on the heat pump's seasonal COP. A heat pump with a COP of 3 delivers 3 kWh of heat per kWh of electricity. At $0.17/kWh that is about $16.60 per million BTU, while gas at $1.50/therm in a 95% furnace costs about $15.80. In cold climates the seasonal COP is lower, and at higher electricity prices gas usually wins on running cost.
What is AFUE?
Annual Fuel Utilization Efficiency is the share of fuel energy a furnace or boiler turns into heat over a typical season. Older furnaces are often 60% to 80% AFUE, mid-efficiency models 80% to 83%, and condensing furnaces 90% to 98.5%.
What COP should I use for a heat pump?
COP (coefficient of performance) is heat out ÷ electricity in. Modern air-source heat pumps average around 2.5 to 3.5 over a heating season in mild and moderate climates, and about 2 to 2.5 in cold climates. Ground-source (geothermal) systems often reach 3.5 to 4.5. If you know the HSPF rating, the seasonal COP is roughly HSPF ÷ 3.412 (an HSPF of 9.5 is about COP 2.8).
How much heat does a home need per year?
A typical US home uses roughly 30 to 90 million BTU of heat per year depending on size, insulation and climate. The best estimate comes from your bills: multiply last year's fuel use by its energy content and your system's efficiency. That is the 'last year's fuel use' option here.
Does this include equipment costs?
No. It compares running costs only. Installation, maintenance, service fees and fixed monthly utility charges are not included, so add those if you are deciding whether to switch systems.
Is my data stored?
No. Everything is calculated in your browser and nothing is sent anywhere.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.