Electric Heat Pump vs Gas Pool Heater: Cost to Run in 2026
A gas pool heater can cost $300–$500/month to run; a heat pump pool heater does the same job for 40–50% less. The trade-off is speed and cold-weather output.
By ElectricVsGas
Heating a pool is one of the few places where the electric-vs-gas gap is enormous. A gas pool heater can cost $300–$500 a month to run during the season, while an electric heat pump pool heater does the same job for roughly $150–$250 — because a heat pump moves heat at a COP of 5–6 rather than burning fuel. The trade-off: gas heats fast and works in any weather, while a heat pump is slow and needs mild ambient temperatures.
Run your own pool size and local rates through the pool heater calculator to see the gap for your setup.
Operating Cost: Heat Pump Wins Decisively
Heating a typical 15,000-gallon pool to maintain swimming temperature over a season costs dramatically different amounts depending on the heater type:
The reason is the same physics behind home heat pumps: a gas heater converts fuel to heat at 80–85% efficiency, while a pool heat pump moves ambient heat into the water at a COP of 5–6 — effectively 500–600% efficient. At national average rates that makes the heat pump 40–50% cheaper than natural gas per unit of heat, and roughly 70% cheaper than propane — a difference that compounds to hundreds of dollars over a season.
Speed and Climate: Where Gas Wins
This is the catch. The numbers above assume the heat pump can do the job, and that depends on weather:
- Heat pumps are slow. They raise water temperature gradually — often 1–2°F per hour — so they work best maintaining a steady temperature, not heating a cold pool on demand.
- Heat pumps need warm air. Below about 50°F ambient, their efficiency and output drop sharply. They’re poorly suited to early-spring or late-fall heating in cold regions.
- Gas heats anything, anytime. A gas heater delivers full output regardless of air temperature and can warm a pool quickly for a spontaneous weekend swim — ideal for occasional or off-season use.
Upfront Cost and Lifespan
| Heat pump | Gas heater | |
|---|---|---|
| Unit cost | $2,000–$5,000 | $1,500–$3,500 |
| Installation | $500–$1,500 | $500–$2,000 (gas line) |
| Lifespan | 10–20 years | 5–10 years |
| Best for | Steady-temp, regular use | On-demand, occasional use |
Heat pumps cost more upfront but last roughly twice as long and cost a fraction to run — so for a pool used regularly through a warm-climate season, the heat pump’s higher purchase price pays back quickly. Gas makes more sense for a pool heated occasionally or in a short, cool shoulder season.
The Cheapest Option: A Pool Cover
Whichever heater you choose, the single most cost-effective add-on is a solar/thermal pool cover. Most pool heat loss is evaporation off the surface; a cover cuts heating costs by 50–70%. Skipping the cover can easily double your numbers above. A solar cover costs $50–$200 and pays back in weeks of heating.
Which Should You Choose?
Choose an electric heat pump if you run the pool regularly through a warm-weather season, live somewhere with mild air temperatures during swim months, and want the lowest running cost. It’s the clear winner on total cost for most recreational pools in warm climates.
Choose gas if you swim occasionally and want heat on demand, extend the season into cool weather, or need to heat a large pool or spa quickly. The high running cost matters less when you only fire it up sometimes.
Many owners use both: a heat pump to maintain temperature economically, with gas for fast heat-ups or cold snaps.
Frequently Asked Questions
Is an electric or gas pool heater cheaper to run?
An electric heat pump pool heater is meaningfully cheaper — typically 40–50% less than natural gas (roughly $225 vs $400 a month for an uncovered 15,000-gallon pool at national average rates) and about 70% less than propane. The heat pump’s COP of 5–6 means it moves five to six times more heat than the electricity it consumes, while a gas heater burns fuel at 80–85% efficiency.
Why would anyone choose a gas pool heater then?
Speed and weather independence. Gas heaters deliver full output in any temperature and can warm a pool quickly for spontaneous use, while heat pumps are slow and lose effectiveness below ~50°F ambient. Gas is the better fit for occasional swimmers, cold-climate shoulder seasons, and large pools or spas that need fast heat-ups.
How much does it cost to heat a pool per month?
For a typical 15,000-gallon pool maintained at swimming temperature with a cover: roughly $100/month with a heat pump, $180 with natural gas, and $340 with propane. Without a cover, expect those figures to roughly double ($225 / $400 / $755). Climate, pool size, and target temperature change the numbers substantially.
Do pool heat pumps work in cold weather?
Not well. Pool heat pumps rely on extracting heat from outdoor air, so their output and efficiency fall sharply below about 50°F. They’re designed for warm-season heating and temperature maintenance, not for warming a pool in early spring or late fall in cold climates — that’s where gas heaters have the advantage.
What’s the cheapest way to heat a pool?
A heat pump paired with a solar/thermal pool cover. The cover alone cuts heat loss 50–70% by stopping surface evaporation, and the heat pump provides the most efficient active heating. A solar cover costs $50–$200 and is the best value upgrade for any pool regardless of heater type.
Data sources: Pool heat pump COP of 5–6 and gas heater efficiency of 80–85% from manufacturer specifications (Hayward, Pentair, Raypak). Operating cost estimates for a 15,000-gallon pool (~400 sq ft surface) maintained at ~82°F with a 17°F water–air temperature difference, using EIA 2025–2026 national average rates ($0.19/kWh electricity, $1.50/therm natural gas) and typical propane pricing ($2.60/gal); surface heat loss ~4.5 BTU/hr·sq ft·°F uncovered. Pool cover savings (50–70%) from U.S. Department of Energy pool heating guidance. Equipment cost and lifespan ranges from HomeAdvisor and pool-equipment retailer pricing, 2025–2026. Actual costs vary heavily with climate, pool size, usage, and cover use.