Home Heating Cost Calculator
See exactly what it costs to heat your home — by fuel type, using your state's live natural gas rate. Compare gas vs. electric vs. propane, and see how much better insulation is worth.
Maine gas costs 2.3× more per therm than Louisiana — same home, same heating days, more than double the bill.
2.3×
More expensive: Maine gas ($1.90/therm) vs. Louisiana ($0.82/therm) — same home, 2.3× the bill
40% more
Energy used by a poor-insulation home vs. a code-minimum 2000s home — the biggest cost lever
50 states
Live state natural gas rates — updated regularly from EIA so you get a real local number
What drives your heating bill
State rates, home size, insulation — the three numbers that matter most.
State gas rates vary by more than 2×
Louisiana pays ~$0.82/therm; Maine pays ~$1.90/therm. The same 1,500 sq ft home heated for 180 days costs about $97/yr in Louisiana and $224/yr in Maine. This isn't a rounding error — it's the difference between heating being a small line item and a significant financial burden. Select your state and the calculator uses the live current rate.
Insulation is the investment with the clearest payback
A pre-1980 home with minimal insulation uses 40% more energy than a code-minimum 2000s home, and 115% more than a passive-house-class home. Whole-home insulation upgrades typically run $5,000–$15,000 and often qualify for federal and utility rebates. The annual saving frequently makes the payback period 8–15 years — but also reduces cooling costs and improves comfort year-round.
Gas vs. electric: it depends on your state
In most states, natural gas is 40–60% cheaper than electric resistance heating at current rates. But the comparison shifts significantly if you have or are considering a heat pump (COP 2–4, not modelled here), or if your state has unusually cheap electricity (Pacific Northwest) or expensive gas (New England). The fuel comparison insight shows you the real dollar difference for your specific state.
How the Home Heating Cost Calculator Works
Formula
// Heat load model (based on ASHRAE 90.1 / EIA RECS 2020)
insulationMultiplier: poor=1.40, average=1.00, good=0.80, excellent=0.65
baseKBtuPerDay = homeSqFt × 0.035 kBtu/(sqft·day) × insulationMultiplier
annualKBtu = baseKBtuPerDay × heatingDays
// Natural gas cost (live state $/therm injected)
thermsNeeded = annualKBtu / 100 kBtu/therm
annualGasCost = (thermsNeeded / 0.80 furnace efficiency) × gasPrice
// Electric resistance cost (live state $/kWh)
annualElecCost = (annualKBtu / 3.412 kBtu/kWh) × electricRate
// Propane cost ($2.60/gal national avg)
annualPropaneCost = (annualKBtu / 91.5 kBtu/gal / 0.80 efficiency) × 2.60
// Example: National avg gas $1.28/therm, 1,500 sq ft, average insulation, 150 heating days
// annualKBtu = 1,500 × 0.035 × 1.00 × 150 = 7,875 kBtu
// therms = 7,875 / 100 = 78.75 therms
// annualGasCost = (78.75 / 0.80) × $1.28 = ~$126/yr (~$11/month)
// Colder climate example: 200 heating days, poor insulation
// annualKBtu = 1,500 × 0.035 × 1.40 × 200 = 14,700 kBtu
// therms = 147; annualGasCost = (147 / 0.80) × $1.28 = ~$235/yrSelect your state
Loads your state's live residential natural gas rate ($/therm). Also loads the electricity rate for comparing against electric heating. Rates range from about $0.82/therm (Louisiana) to $1.90/therm (Maine).
Set heating days per year
How many days per year does your heating system run? Deep South: 40–80 days. Mid-Atlantic/Midwest: 150–180 days. New England/northern states: 200–230 days.
Enter home size
Heated square footage. US median is ~1,500–1,800 sq ft. Only count conditioned (heated) space — unheated garages and basements don't count.
Select heat source
Gas furnace (most common), electric resistance (baseboard heaters, electric furnace), or propane (common in rural areas without gas access). The calculator shows all three so you can compare.
Select insulation quality
Poor = pre-1980 minimal insulation (uses 40% more energy than average). Average = code-minimum 2000s home. Good = well-insulated, air-sealed. Excellent = passive-house-class (uses 35% less than average).
The heating load model uses a base of 0.035 kBtu per square foot per heating day — derived from EIA RECS 2020 residential heating data and ASHRAE 90.1 envelope assumptions for a reference code-minimum 2000s home in a moderate US climate. The insulation multipliers are from DOE Building America research and ACEEE residential efficiency data.
Gas furnace efficiency is modelled at 80% AFUE — the median of the installed US fleet per EIA RECS 2020. High-efficiency condensing furnaces (96% AFUE) are growing in the new-installation market but remain a minority of installed systems. Electric resistance heating is modelled at 100% efficiency (COP = 1.0). Heat pumps (COP 2–4) are not modelled here; see our EV vs. Gas calculator for a sense of the economics of electrification.
Natural gas prices are all-in residential retail prices including commodity cost and local distribution/delivery charges, sourced from EIA Natural Gas Monthly by state. These are refreshed regularly so you get current prices rather than a stale national average.
Frequently Asked Questions
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