Pool heater types on a daylight equipment pad with solar panels in background

Pool Heater Buyer's Guide: Gas vs Heat Pump vs Solar

If you’re heating a pool, you have three viable options: gas, electric heat pump, or solar. Each has a clear sweet spot and a clear “don’t pick me for this scenario.” This buyer’s guide breaks down which heater type fits which pool and climate.

Gas heaters (natural gas or propane)

The fastest-heating option. A 400,000 BTU gas heater can raise a 20,000 gallon pool 1°F per hour — useful when you need pool-ready water for a party tomorrow. Downsides: fuel cost runs $5–$15 per hour of operation depending on local gas prices and propane vs. natural gas.

Best for: spas, occasional pool heating, pools in regions with cheap natural gas, or anyone who needs “heat to 88°F by Saturday afternoon” flexibility.

Worst for: daily heating in cold climates. Operating cost adds up fast.

Heat pumps

The most energy-efficient option for sustained pool heating. A heat pump uses electricity to pull warmth from outside air and dump it into the pool — 4–6 units of heat out for every 1 unit of electricity in. Slow to come up to temperature (3–5 days to raise a cold pool 10°F) but cheap to maintain a target temperature.

Best for: daily-use pools in moderate climates (above 50°F ambient most days). Pool owners who keep the pool at a target temperature all season.

Worst for: cold climates where ambient drops below 50°F often (heat pumps lose efficiency, and most stop working entirely below 45°F). Pools that only swim 2 days a week (the heat pump runs constantly to maintain temperature you’re not using).

Solar heating

The cheapest to operate. Solar collector panels mounted on a roof use the pump’s flow to push pool water through black absorber tubes that heat from sunlight. Operating cost is essentially zero. Initial install runs $3,000–$7,000.

Best for: sunny climates, large south-facing roofs, owners willing to accept “heated when the sun cooperates” rather than “heated on demand.”

Worst for: shaded yards, cloudy regions, owners who want guaranteed 85°F water on a specific date. Solar can extend your swim season by 6–8 weeks but won’t heat a cold pool fast.

The hybrid approach

Many pool owners run two systems: solar for daily maintenance, gas for fast top-ups before a weekend party. The gas heater idles 90% of the time while solar does the work, and only fires when you need quick heat. Operating cost stays low; flexibility stays high.

Parts and accessories at PST

Sizing tip: for gas heaters, target 100–125 BTU per gallon of pool. For heat pumps, target 100,000 BTU output per 20,000 gallons. Undersize either and you’ll run them constantly without hitting target temperature.

Need help picking heater type, BTU rating, or gas vs propane vs heat pump for your specific climate? Send PST Pool Supplies your pool gallons, location, and intended use pattern. We’ll match the right heater and the install accessories you’ll need.

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