Electric resistance vs air-to-water heat pump vs natural gas boiler. Bin-hour analysis using climate normals from any of the 122 NOAA Weather Forecast Offices.
Hourly heating power required across winter temperature bins (kBTU/hr) and the corresponding heat pump COP at each bin.
Climate data from NOAA climate normals (1991–2020) for each Weather Forecast Office. Bin-hour distribution modeled from each city's HDD65 and 99% heating design temperature using a temperature distribution fit. Heat pump COP curve linearly interpolated from outdoor temperature, with backup electric resistance kicking in below the heat pump's balance point. Electric resistance assumed 100% efficient. Gas boiler assumed 95% AFUE. Does not include domestic hot water, standby losses, or distribution losses. Real-world costs typically run 5–15% higher across the board.
Electric resistance heating passes current through a resistive material — nichrome wire in older systems, a carbon-loaded polymer in newer products like STEP Warmfloor — and the material's electrical resistance converts every watt of electricity directly into a watt of heat. The conversion is essentially 100% efficient, but that's also the ceiling. There's no thermodynamic trick available; one kilowatt-hour in always equals 3,412 BTU out.
The appeal is mechanical simplicity. No combustion, no refrigerant, no plumbing, no boiler room, no annual service. STEP's self-regulating PTC polymer adds a genuine safety advantage — the elements physically can't overheat — and the thin profile (about 1mm) means installation rarely affects floor heights, doors, or trim. For a luxury floor-warming layer in a bathroom or kitchen, that simplicity is worth paying for.
The drawback is the operating cost. At typical US electricity rates, heating a whole 3,000 sq ft house with resistance elements runs roughly three times more than either of the alternatives below. A whole-house resistance system also demands serious electrical service (often 400A) and dedicated circuits throughout. The right use case is small areas and supplemental warmth, not the primary heat source for a large home.
A heat pump doesn't generate heat — it moves heat from outside air into water that circulates through your radiant floor or fan coils. Because it's transferring rather than creating energy, one kilowatt-hour of electricity can deliver three or four kilowatt-hours of heat into the house. That ratio is the coefficient of performance (COP), and it's what makes heat pumps the most efficient electric heating option by a wide margin.
The catch is that COP depends on outdoor temperature. When it's 47°F outside, a good unit easily hits a COP of 4. When it drops to 17°F, that same unit may only manage 2.0 to 2.8 depending on the model. Below the balance point, electric resistance backup kicks in to make up the shortfall, and efficiency collapses. The seasonal COP — the weighted average across all the hours you actually run the system — is the number that matters for your annual bill, and it's typically well below the rated peak.
For cold climates, a true cold-climate heat pump (Mitsubishi Hyper-Heat, Fujitsu XLTH, Bosch IDS, Chiltrix, SpacePak Solstice, etc.) is worth the price premium because it holds high COP down to 5°F and rarely needs the resistance backup. As a bonus, the same unit reverses in summer to provide chilled water for cooling, and it can pre-heat domestic hot water through a buffer tank. Federal tax credits (currently $2,000 for qualifying units) and state/utility rebates often stack into meaningful incentives.
A modern condensing gas boiler burns natural gas to heat water, capturing latent heat from the flue gases by condensing the water vapor. That second-stage recovery is what gets the efficiency above 90% — modulating-condensing (mod-con) units typically run between 92% and 96% AFUE. The boiler then circulates hot water through your radiant tubing or panel radiators using small electric pumps that draw under 200 watts total.
Operating cost is competitive with a heat pump in most US utility territories and often slightly cheaper in regions where natural gas is cheap relative to electricity. A boiler also has the advantage of consistent output regardless of outdoor temperature — no COP collapse on the coldest days, no backup elements to worry about. Installation cost is typically the lowest of the three serious whole-house options, and the equipment fits in a small mechanical room or closet.
The downsides are combustion-related. You need a gas line, a flue or sidewall vent, combustion air, and an annual service visit to check the burner and heat exchanger. There's no cooling capability, so you'll need a separate AC system. Carbon emissions are real, and the long-term direction of building codes and utility rates is moving against fossil-fuel heating — though for the next 15 to 20 years, gas remains the lowest-friction, lowest-installation-cost option for cold-climate hydronic heat. Many homeowners pair a heat pump (carrying 85–95% of annual load) with a gas boiler (handling the coldest days and providing redundancy) to get the best of both.