Powering Your Pump & Heater with Solar
What a pool actually costs to run
Two things drive pool electricity use:
- The pump. A pool pump runs for hours every day to circulate and filter water. Older single-speed pumps are especially hungry — often one of the largest single loads in the whole house. A variable-speed pump is far more efficient but is still a daily, recurring draw.
- The heater. An electric heat-pump pool heater typically draws around 5–6 kWh per hour and can use 15–25 kWh on a day you’re heating — roughly $50 to $150+ a month in the swim season, and more if you like the water warm. As a rule of thumb, every degree warmer you keep the pool adds roughly 10% to heating cost.
Add the pump and heater together and a heated San Diego pool can rival — or beat — air conditioning as your top summer electricity expense. Many pool owners are surprised to learn that the “mystery” behind their high bill isn’t the house at all; it’s the equipment in the side yard.
Why solar is a natural fit for pool loads
Here’s what makes pools such a good match for solar: most pool electricity is used during the day. Pumps are typically scheduled to run in daylight hours, and heat-pump heaters work most efficiently when the air is warm — again, daytime. That’s precisely when your panels are producing.
So instead of buying grid power to run the pump and heater, you can run them straight off your roof. Because it’s a daytime load, a pool is one of the easiest things to cover with solar — you don’t even need a battery to offset it, since the pump, the heater, and the sun are all “on” at the same time. That’s a genuinely favorable overlap: the appliance you’re trying to power and the free energy source are naturally in sync.
Timing the pump to your solar
One of the simplest, highest-impact moves is scheduling. If you shift your pump (and heating) to run during the middle of the day — say the 10 a.m.–2 p.m. window, which is also SDG&E’s cheap super off-peak period in 2026 — you accomplish two things at once:
- You run it on your own solar production, using power you’re generating for free rather than buying it.
- Any grid power you do draw is billed at the lowest rate of the day (~38¢ super off-peak) instead of the ~70¢ 4–9 p.m. peak.
The one thing you want to avoid is running the pump or heater during that 4–9 p.m. peak. A variable-speed pump on a smart daytime schedule, paired with solar, is a genuinely powerful combination for a pool owner — often the difference between a pool that’s a budget headache and one that barely registers on the bill.
How much can solar offset?
For a home with a pool, adding the pool’s daytime load into the system design usually means a somewhat larger array — but because the load is daytime and predictable, solar can offset the large majority of it. When we size a system for a pool home, we account for the pump schedule and the heater’s draw so your array is big enough to carry both the house and the pool through summer.
If you also heat the pool deep into the evening or into the cooler shoulder seasons, a battery can extend your own solar into those hours — but for most pool owners, the biggest win is simply generating your own daytime power and running the pool on it.
What affects how much solar you’ll need
- Pump type and runtime. A variable-speed pump on a sensible schedule needs far fewer panels to offset than an old single-speed unit running long hours.
- Whether you heat, and how warm. An unheated pool is basically just the pump. A pool kept at 85° for much of the year is a much bigger load — and a bigger solar opportunity.
- Swim season length. San Diego’s long season is a double-edged sword: more months of enjoyment, but more months of pump and heater runtime to plan for.
The solar pool-heating option
Worth a mention: beyond powering an electric heater with PV, some homeowners also look at dedicated solar thermal pool heating — roof or ground collectors that warm the water directly using the sun’s heat rather than making electricity. It’s a different technology from the electricity-generating panels this post is about, and which approach makes sense depends on your setup, your roof, and how you use the pool. It’s a good thing to raise when you plan a system so you can compare the options side by side.
A few quick questions
Do I need a battery to offset my pool? Usually not. Because the pump and heater run during daylight, panels can cover them directly. A battery helps if you heat into the evening, but it isn’t required for daytime pool loads.
Will adding a pool load make my system huge? It makes it somewhat larger, but pools are efficient to offset precisely because the load is daytime and predictable — exactly when solar is producing.
What’s the single biggest money-saver? Scheduling. Moving the pump to midday, on solar and off the peak, is free to do and immediately effective.
The bottom line
A pool doesn’t have to be the reason your summer bill hurts. Because the pump and heater run during the day, solar can offset most of your pool’s electricity — and scheduling those loads to midday makes the match even tighter. The key is designing the system with the pool load in mind from the start, rather than treating it as an afterthought.
Want to see how much of your pool’s running costs solar could cover? Stellar Solar has been San Diego’s trusted solar installer since 1998 — A+ rated with the BBB and a repeat winner of San Diego’s Best Solar in the Union-Tribune Readers Poll. Get a free estimate that factors in your pool at your free quote here or call 866.787.6527.
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