“Electric pool heater” can mean two very different machines: electric resistance, which turns electricity directly into heat, and a heat pump, which uses electricity to move heat from the air into the water. Lumping them together can spoil the comparison before it begins.
“Electric pool heater” can mean two very different machines: electric resistance, which turns electricity directly into heat, and a heat pump, which uses electricity to move heat from the air into the water. Lumping them together can spoil the comparison before it begins.
Gas: buy speed and independence from warm air
Gas heaters are commonly selected for high recovery and occasional, scheduled heating. Cost depends on delivered efficiency, fuel rate and the size of the temperature lift. The installation may require changes to the meter, regulator, fuel line, venting or combustion-air arrangement. Propane and natural gas also need separate price calculations.
Electric resistance: simple math, demanding load
At the water-only level, required kWh equals BTUs divided by 3,412. Resistance heating can suit small bodies of water or particular installations, but large pools can impose substantial electrical demand. The panel, breaker, conductor, disconnect and local code must be checked before the appliance price becomes meaningful.
Heat pump: efficiency tied to conditions
A heat pump's COP can make each purchased kWh deliver several kWh-equivalents of heat at favorable rating conditions. Output and COP generally need to be evaluated against actual air temperature, humidity and water temperature. The unit also requires open airflow and may not match gas-like recovery in every climate.
Compare one identical heating job
Take 15,000 gallons through a 6°F rise: 750,600 BTU to the water before losses. For gas, divide by thermal efficiency and price the resulting therms. For resistance, divide by 3,412 and price kWh. For a heat pump, divide those resistance kWh by COP at the relevant condition. Add heating-related pump runtime to every applicable case.
Then compare the calendar
A household heating daily in warm weather may reach a different conclusion from one heating a spa on demand during cool evenings. Include desired notice time, swim season, noise location, utility capacity, maintenance access and the value of keeping the pool usable in marginal weather.
Hybrid can be rational
Some properties pair a heat pump for routine maintenance with gas for rapid recovery or a spa. That adds purchase and maintenance complexity, so it is not automatically economical. Model the actual split of hours rather than assuming a hybrid is the best of both worlds.
The winning system is the one that completes the homeowner's recurring heating job at an acceptable total cost. Fuel price alone answers only one line of that decision.
Frequently asked questions
Is a heat pump cheaper to run than a gas pool heater?
It can use less purchased energy in favorable conditions, but local rates, COP, climate, target temperature and required recovery speed determine the actual result.
Is electric resistance the same as a pool heat pump?
No. Resistance creates heat from electricity; a heat pump uses electricity to move heat from outdoor air into pool water.
Which heats a pool fastest?
Compare delivered BTU/h at the conditions of use. Many gas units are designed for high recovery, but exact model ratings and installation support decide.