Home heating is one of the largest drivers of residential emissions in cold US states. For a household in Minnesota or Massachusetts, heating alone can represent 2–5 tCO₂e per year — a larger share of their footprint than all food emissions combined. The choice between natural gas and electric heating, specifically heat pumps, is therefore one of the highest-impact decisions available to US homeowners.
The answer is not the same in every state. Grid intensity determines whether electric heating outperforms gas, and by how much.
Natural gas: the baseline
The EPA emission factor for natural gas combustion is 5.3 kg CO₂ per therm. A typical US home in a cold climate uses 600–800 therms per year for space heating and hot water combined.
| Annual gas use | Annual emissions (tCO₂e) |
|---|---|
| 500 therms (mild climate) | 2.7 |
| 700 therms (average) | 3.7 |
| 900 therms (cold climate) | 4.8 |
Source: EPA Greenhouse Gas Equivalencies Calculator; EIA Residential Energy Consumption Survey.
These are direct combustion emissions only. Natural gas also involves upstream methane leakage during extraction and distribution — estimates vary, but the EPA’s comprehensive accounting includes these in its national inventory figures.
|
Natural gas furnace
Heating demand
↓
Therms consumed
Furnace efficiency ~80% ↓
× 5.3 kg CO₂/therm
EPA combustion factor ↓
Annual tCO₂e
Fixed — independent of grid |
Heat pump (COP 3)
Heating demand
↓
÷ COP 3 = kWh consumed
3 units heat per unit electricity ↓
× grid intensity (kg CO₂/kWh)
EPA eGRID — varies by state ↓
Annual tCO₂e
Improves as grid decarbonizes |
Source: EPA Greenhouse Gas Equivalencies Calculator · EPA eGRID 2023 · IEA Heat Pumps 2022
Electric resistance heating: not the right comparison
Electric resistance heating — baseboard heaters, electric furnaces — converts electricity to heat at a 1:1 ratio. It is inefficient and expensive to run. At the US national average grid intensity of 0.38 kg CO₂/kWh, heating a home with electric resistance requires roughly 2–3× the emissions of an efficient heat pump for the same heat output.
Electric resistance heating is not the relevant comparison for decarbonisation decisions. Heat pumps are.
Heat pumps: how the comparison actually works
A heat pump does not generate heat — it moves it. By extracting heat from outdoor air (or ground) and moving it indoors, a heat pump delivers 2–4 units of heat energy for every unit of electricity consumed. This ratio is called the Coefficient of Performance (COP).
At a COP of 3 — typical for a modern air-source heat pump in moderate climates — the electricity required to deliver the same heat output as a gas furnace is roughly one-third of what electric resistance would require.
| Heating system | Annual electricity / fuel use | Annual emissions (tCO₂e) — national avg grid |
|---|---|---|
| Gas furnace (700 therms) | 700 therms gas | 3.7 |
| Electric resistance | ~20,000 kWh | 7.6 |
| Heat pump (COP 3) | ~7,000 kWh | 2.7 |
| Heat pump (COP 3, Vermont grid) | ~7,000 kWh | 0.08 |
Source: EPA emission factors for natural gas and electricity; EPA eGRID 2023; IEA heat pump efficiency data.
On the national average grid, a heat pump with COP 3 produces comparable emissions to a gas furnace. On a clean grid, it is dramatically lower. As the grid decarbonizes, heat pump emissions fall automatically — a gas furnace’s emissions do not change.
The cold climate caveat
Heat pump performance declines at very low outdoor temperatures. Older models struggled below freezing. Modern cold-climate heat pumps — designed for markets like Scandinavia and Canada — maintain efficiency down to -15°C (5°F) or below. Source: IEA Heat Pumps report, 2022.
In northern US states with cold winters, a cold-climate heat pump is the relevant product, not a standard unit. Performance data from the Northeast US Heat Pump Cold Climate Accelerator confirms that modern cold-climate units maintain COP of 2–2.5 even in harsh winter conditions — still significantly more efficient than electric resistance or comparable to gas, depending on grid intensity.
Grid intensity is the deciding variable
| Grid region | Heat pump emissions vs gas furnace |
|---|---|
| Vermont, Washington, Oregon | 90–95% lower than gas |
| California, New York | 60–75% lower than gas |
| National average | Roughly comparable, slight advantage to heat pump |
| Wyoming, West Virginia | Gas furnace slightly lower currently |
Source: EPA eGRID 2023 state emission rates applied to heat pump COP 3 performance.
In most US states, a heat pump already outperforms or matches gas. In the remaining coal-heavy states, the margin will shift as grids decarbonize — purchasing a heat pump today means locking in improving emissions over the equipment’s 15–20 year lifespan.
The total cost picture
Emissions aside, heat pumps typically reduce energy bills in regions with moderate electricity prices because their efficiency advantage more than offsets electricity’s per-unit cost premium over gas. The economics vary by state electricity and gas prices. The Inflation Reduction Act provides federal tax credits of up to $2,000 for heat pump installation, reducing upfront cost.
This article focuses on emissions rather than economics, but the two often align — particularly for households in states with high gas prices or low electricity rates.
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