What a heated pool actually adds to your solar needs
The baseline addition for a typical pool
A medium pool with a heat pump heater in a moderate climate needs about 4.8 kW of extra solar capacity, around 12 panels. For a full-home baseline to add this on top of, see the fixed-size home tools. The same pool in a hot climate with a longer swim season needs closer to 7.2 kW, a real jump from climate alone.
The pool pump runs year round, regardless of heating
A pool pump uses roughly 2,500 kWh a year on its own, circulating and filtering water whether or not the pool is heated, though the real figure varies more than that single number suggests. A standard single-speed pump commonly uses 3,000 kWh or more annually, while a variable-speed pump doing the same job can use under 1,000. This tool includes a middle-ground pump estimate in every scenario, even a gas-heated pool, since the pump itself stays electric either way. ENERGY STAR's pool pump guide explains how variable-speed pumps cut that use.
Why climate matters more than heater efficiency alone
Climate decides how many days a year the pool actually needs heating to stay swimmable, ranging from as few as 90 heating days in a cold climate to as many as 300 in a hot one. That swing in season length can matter more to the final number than the heat pump's own efficiency rating, a comparison the annual kWh output estimator can help translate into an actual production figure for your climate.
Why a gas-heated pool needs far less solar capacity
A gas pool heater keeps the heating load off the electric bill entirely, leaving only the pool pump's roughly 2,500 kWh a year as extra solar capacity. That's a much smaller addition than an electric heat pump pool heater, which can add several thousand more kWh a year depending on climate and pool size, since heat pump pool heaters move existing heat rather than burning fuel to create it, running far more efficiently than a gas heater's 80 to 90% thermal efficiency. The Department of Energy's homeowner's guide to solar covers sizing for homes with heavy electric loads like a heated pool.
What to do with this number next
Add this extra capacity to whatever your existing system already covers, then check the federal ITC calculator for pool equipment specific programs, which sometimes stack with solar incentives. Once your pool is running, the monthly usage tool can confirm the real number against an actual bill.