Solar for a Pool in California: Powering the Pump vs Heating the Water
Straight answer: “solar for a pool” means one of two things. Solar panels (PV) make electricity, which runs the pool pump; solar collectors heat the water and make no electricity. For the pump, start with the pump itself: moving the same 20,000 gallons once a day, an old single-speed pump uses about 1,960–4,030 kWh a year and a new variable-speed pump about 850–1,110 in DOE and ENERGY STAR test data — roughly two 400 W panels’ output in Los Angeles. For heat, a new pool heated under a permit filed since January 1, 2026 must get its main heat from solar collectors or a heat pump; gas can only back them up.
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- “Solar for a pool” is two different systems: solar panels (PV) make electricity for the pump; solar collectors heat the water and make no electricity. You can have both.
- Fix the pump first. Moving the same 20,000 gallons a day, a new variable-speed pump uses about 850–1,110 kWh a year against 1,960–4,030 for an old single-speed one. The difference is the output of roughly one to five panels in Los Angeles.
- Run it slow and long. In ENERGY STAR test data the same water takes about 3.2 times the energy at high speed as at low speed. On SCE, run it through late morning and midday and finish by 4 p.m.; on LADWP’s net metering, total kWh matters more than timing.
- Federal standards push new in-ground pumps (since 2021) and replacement motors (since September 29, 2025) to variable speed. LADWP pays a $500 rebate on a qualifying one.
- For a new pool permitted since January 1, 2026, the main heater must be solar collectors (at least 60% of the pool surface on a single-family home) or a heat pump. Existing pools that already have a heater are exempt.
Which kind of solar does your pool need?
Start from what you want the pool to do. Each goal has its own equipment, and 2026 changed the rules for one of them.
| Your goal | What to install | What it does | What to know in 2026 |
|---|---|---|---|
| Lower what the pool costs to run | A variable-speed pump, then solar panels sized to its kWh | The pump is the pool’s main electric load; the panels supply that electricity | A new pump needs about two panels’ output in our example; LADWP rebates $500 |
| Warm the water with the sun | Solar pool collectors, usually on the roof | Pool water runs through them and returns warmer; they make no electricity | To count as a new single-family pool’s heater, at least 60% of the pool surface; solar-only pools are exempt from the sizing |
| Warm the water on demand | A heat-pump pool heater, with panels covering its electricity | Uses electricity to move heat from the air into the water | Allowed as a new pool’s main heater; an outdoor pool with one needs a cover |
| Heat with gas | A gas pool heater | Burns gas; no solar role | On a new pool, only as a backup since January 1, 2026; existing heated pools are exempt |
Rules: California Energy Commission, 2025 Energy Code §110.4. Pump figures: the worked example below.
How much electricity a pool pump uses — and how many panels cover it
ENERGY STAR says a pool pump could be a home’s second-largest energy user. How large depends on the pump far more than on the pool.
To compare pumps fairly, the table holds one job constant: moving the water of a 20,000-gallon pool — a 16-by-32-foot pool about five feet deep on average — through the filter once a day, all year. One turnover a day is what the pool industry recommends for homes, according to DOE’s rulemaking record, and DOE assumes California pools run twelve months a year (DOE). Only the pump changes.
| Pump and how it runs | Gallons moved per kWh | kWh a year | Cost at 26¢/kWh | Solar to match it |
|---|---|---|---|---|
| Old single-speed pump (range on the market in DOE’s data) | 1,810–3,730 | 1,960–4,030 | $510–$1,050 | 1.2–2.4 kW (3–7 panels) |
| New variable-speed pump: federal minimum to ENERGY STAR median | 6,590–8,600 | 850–1,110 | $220–$290 | 0.5–0.7 kW (2 panels) |
| Same ENERGY STAR pump, filtering only at low speed (about 31 gpm, 10.7 hours a day) | 16,000 | 460 | $120 | 0.3 kW (1 panel) |
| Same pump only at high speed (about 63 gpm, 5.3 hours a day) | 5,000 | 1,450 | $380 | 0.9 kW (3 panels) |
Gallons per kWh is the federal weighted energy factor (WEF). Single-speed range: DOE’s 2017 market data for standard-size in-ground pumps. 6,590 is the federal minimum for a 1-hydraulic-horsepower in-ground pump; 8,600 is the median of 320 ENERGY STAR–certified variable-speed in-ground pumps, whose low- and high-speed test points give the last two rows (medians). The tests use a standard pipe curve (head = 0.0082 × flow²), the same equation California’s Energy Code uses for pools over 17,000 gallons. Solar at 1,676 kWh per kW a year (Los Angeles, PVGIS, as in our sizing guide) with 400 W panels; 26¢ is SCE’s TOU-D-PRIME price outside 4–9 p.m. in summer. Estimates, not guarantees.
Two things stand out. Swapping an old single-speed pump for a variable-speed one removes about 850–3,200 kWh a year — what 0.5–1.9 kW of panels would make — before you buy a single panel. And a variable-speed pump only saves if it actually runs slowly: pushed through at high speed, the same water takes about 3.2 times as much energy as at low speed. Real pools add resistance the test curve leaves out — a heater, long pipe runs, a cleaner, roof collectors — so expect your own figures to come in higher. To turn kWh into a whole-house system size, see how many solar panels you need.
Three lines of arithmetic
1. Daily energy: watts × hours at each speed, added up. Many variable-speed pumps show their watts on the control panel or in the app; for a single-speed pump, the nameplate volts × amps gives a high-side estimate.
2. Yearly energy: × 365 days ÷ 1,000 = kWh a year (fewer days if the pump is off part of the year).
3. Solar: ÷ 1,676 = kW of panels in Los Angeles; ÷ 0.4 = 400 W panels, rounded up.
Example: 300 W for 10 hours plus 1,100 W for 2 hours = 5.2 kWh a day = 1,898 kWh a year = 1.13 kW = 3 panels.
Run it slow, long — and on SCE, in solar hours
When the pump runs matters on some rates. How fast it runs matters on all of them.
A pump’s power falls much faster than its speed: at half speed it draws about one-eighth the power (ENERGY STAR). It then needs twice as long to move the same water, so the energy per gallon still drops by about three-quarters in theory, and by about two-thirds in the test data above. The cheapest schedule is the lowest speed that keeps the water clean, for as long as one turnover takes — not a fast run squeezed into a few hours. California’s Energy Code builds the same idea into new pools: filtration flow may not exceed the rate that turns the water over in six hours (or 36 gpm, whichever is greater), multi-speed pumps must default back to that filtration speed, and a time switch must let the pumps run off-peak (CEC).
On SCE and the other utilities on the Net Billing Tariff, timing is worth real money. A midday export from a 2026 system earns about 6¢ per kWh in summer and 3¢ in winter, plus a 1.6¢ bonus (SCE), while the TOU-D-PRIME rate that Solar Billing Plan customers use charges 26¢ outside 4–9 p.m. in summer and 24¢ from 8 a.m. to 4 p.m. in winter (SCE). Each pump kWh moved from the night onto your own midday surplus is worth about 18–19¢; one moved out of a summer-weekday 4–9 p.m. window, about 53¢. Start the run in the morning so it covers late morning and midday and finishes by 4 p.m.; our SCE appliance schedule has the windows for every plan.
On LADWP, the standard R-1A rate nets the kilowatt-hours you export against those you buy over the billing period, so the pump’s yearly kWh matters more than when it runs (LADWP). The time-of-use R-1B rate is priced highest from 1 to 5 p.m. on weekdays and credits each export at its own time block’s price. More in LADWP net metering in 2026.
No battery needed for the pump. It runs in daylight, when the panels do. A battery is about evenings and outages, not filtration — see do I need a battery under NEM 3.0?
Is a variable-speed pump required — and is there a rebate?
For a new in-ground pump, effectively yes. For a replacement motor, increasingly yes.
Federal standards in force since July 19, 2021 set a minimum efficiency for standard-size in-ground (self-priming) filter pumps — 0.711 to 2.5 hydraulic horsepower — that DOE built around a variable-speed motor; smaller pumps, above-ground pumps and cleaner booster pumps can still comply with an efficient single-speed motor (DOE, 10 CFR 431.465). Since September 29, 2025, a replacement pool-pump motor of 1.15 to 5 total horsepower must itself be variable-speed; motors from 0.5 horsepower follow on September 28, 2027 (10 CFR 431.485). The dates apply to equipment as it is manufactured, so older stock can still turn up. DOE estimated that the variable-speed requirement for standard-size motors pays back in about 1.3 years on average nationwide (DOE).
Rebate. LADWP’s Consumer Rebate Program pays $500 for a qualifying variable-speed or variable-flow pool pump and motor, one per home, for models on its qualifying list. A summer special paid $750 for equipment bought and installed from June 1 to September 30, 2026, if the application arrives by December 31, 2026 (LADWP). Rebates change; check the program page before you buy.
Heating the water: California’s rule since January 1, 2026
For a new pool, the choice of heater is no longer open.
California’s 2025 Energy Code applies to permit applications filed on or after January 1, 2026 (CEC). It requires a pool or spa heating system to meet one of these: solar collectors with a surface area of at least 60% of the pool or spa surface on a single-family home (65% for multifamily and nonresidential pools); a heat-pump pool heater as the primary heater, sized to the code’s appendix, with a backup of any fuel; at least 60% of the annual heat from on-site renewable or recovered energy; or solar collectors plus a heat pump with no other backup (CEC, §110.4(c)). In practice, gas can still back up a heat pump but can no longer be a new pool’s main heater.
The rule has exceptions. The main one for homeowners: alterations to an existing pool or spa that already has heating equipment are exempt, so replacing the heater on an existing heated pool isn’t forced off gas. A pool heated only by solar, with no backup heater, also escapes the 60% sizing. The same section requires a cover on any outdoor pool or spa heated by electric or gas equipment, plumbing that leaves room to add solar heating later, and the time switch mentioned above. This is general information, not code advice; your building department applies the code to your permit.
Solar collectors or a heat pump running on your panels?
Both meet the 2026 rule. They differ in roof space, electricity and when they deliver heat.
Collectors need roof
The 60% minimum for our 16-by-32-foot example pool (512 sq ft) is 307 sq ft of collectors. DOE’s guidance ran from 50% to 100% of the pool surface, more in cooler or cloudier places. That is about as much roof as a whole-house PV system: the seventeen-panel array in our sizing guide covers 332 sq ft. Plan both together.
Collectors work the pump harder
Water has to be pushed up to the roof and through the collectors. DOE noted you may need a larger pump or a separate, smaller pump for the collectors. On a variable-speed pump that means a faster setting during heating hours — midday, when the panels produce most.
A heat pump uses electricity
Warming 20,000 gallons by 10°F takes about 489 kWh of heat. A heat pump delivers several units of heat per unit of electricity — at an illustrative ratio of 5, about 98 kWh — and keeping the pool warm takes more every day. Heat pumps do more per kWh in warm air, so on SCE the warm hours before 4 p.m., when your panels produce, suit them best.
Cover it either way
Evaporation is by far a pool’s largest heat loss, and DOE put the savings from covering a pool when it isn’t in use at 50–70%. A cover also lets you use a smaller collector.
Sources: DOE Energy Saver pages on solar pool heaters and pool covers (archived March 2025, since taken offline); CEC 2025 Energy Code. Heat arithmetic: 20,000 gal × 8.34 lb × 10°F = 1.67 million Btu ÷ 3,412 = 489 kWh.
Cost and credits. DOE’s consumer guide put a solar pool heating system at $2,500–$4,000 to buy and install, with a payback of one to seven years depending on local fuel costs; the guide is no longer online, and current quotes vary with collector area and roof. There is no federal tax credit in 2026 for collectors or panels a homeowner buys: the Residential Clean Energy Credit does not apply to property placed in service after December 31, 2025 (IRS). For panel prices, see what solar costs in Los Angeles.
The bottom line for LA pool owners
For most Los Angeles and San Fernando Valley pools the order is: (1) put in a variable-speed pump if you don’t have one — on LADWP, with a $500 rebate; (2) run it at the lowest speed that keeps the water clean, finishing by 4 p.m. on SCE; (3) size solar for the pump’s real kWh — one to three panels’ worth for a modern pump in our example; (4) if you want warm water, choose collectors if you have the roof and a heat pump if you want heat on demand, and cover the pool either way. Every figure here is an estimate from test data and published rates, not a guarantee — your pump, plumbing, pool and utility move the numbers.
Where Cali Energy fits. The pool equipment itself is a pool contractor’s job. Our part is the solar and electrical side: sizing panels for the pool’s real kWh, leaving roof space if collectors are coming too, and checking whether your electrical panel can carry a 240-volt heat-pump heater. Call +1-323-844-7777 or get a free estimate.
Frequently asked
Can solar panels run my pool pump?
Yes. Panels make electricity, and a pump is a steady daytime load. Moving a 20,000-gallon pool’s water once a day, a new variable-speed pump uses about 850–1,110 kWh a year in DOE and ENERGY STAR test data — about two 400 W panels’ output in Los Angeles. An old single-speed pump uses about 1,960–4,030 kWh, or three to seven panels. Real systems with a heater or long pipe runs use more.
How many solar panels do I need for a pool pump?
Multiply the pump’s watts by its daily hours at each speed, then by 365, and divide by 1,000 for kWh a year. Divide by about 1,676 kWh per kW (Los Angeles) for kW of panels, then by 0.4 for 400 W panels, rounded up. Example: 300 W for 10 hours plus 1,100 W for 2 hours is 1,898 kWh a year, or three panels.
When should I run my pool pump if I have solar?
At the lowest speed that keeps the water clean, for as long as one turnover takes. On SCE, run it through late morning and midday and finish by 4 p.m.: each kWh moved onto your midday surplus is worth about 18–19¢ against exporting it. On LADWP’s standard rate, exports net against purchases, so total kWh matters more than timing.
Do I need a variable-speed pool pump in California?
For a new standard-size in-ground pump, effectively yes: the federal standard in force since July 19, 2021 was built around variable-speed motors. Replacement motors of 1.15–5 total horsepower made since September 29, 2025 must be variable-speed, and motors from 0.5 hp follow on September 28, 2027. LADWP pays a $500 rebate on a qualifying model.
Can I still install a gas pool heater in California?
Not as the main heater for a new pool. For permits applied for since January 1, 2026, California’s Energy Code requires solar collectors (at least 60% of the pool surface on a single-family home), a heat-pump heater or another qualifying renewable system; gas can back up a heat pump. Alterations to existing pools that already have a heater are exempt. Confirm with your building department.
How big does a solar pool heater need to be?
To count as a new single-family pool’s heater under the 2026 code, the collectors must equal at least 60% of the pool’s surface area — 307 sq ft for a 16-by-32-foot pool. A pool heated only by solar, with no backup heater, is exempt from that sizing. DOE’s guidance ran 50–100%, more in cooler or cloudier places, and a pool cover lets you use less.
Do I need a battery to run my pool on solar?
Not for the pump. It runs in daylight, when your panels produce. A battery is about evenings, outages and the 4–9 p.m. peak, not filtration — see do I need a battery under NEM 3.0?
Related reading
Sources & methodology
Figures on this page come from the primary sources below and, where noted, from Cali Energy calculations using the stated assumptions. Rates, incentives, and program terms change; each was verified October 1, 2026.
- ENERGY STAR — Pool Pumps
- ENERGY STAR — Certified Pool Pumps (product test data, accessed October 1, 2026)
- Federal Register — DOE energy conservation standards for dedicated-purpose pool pumps (January 18, 2017)
- eCFR — 10 CFR 431.465, energy conservation standards for pumps, including pool pumps
- Federal Register — DOE energy conservation standards for dedicated-purpose pool pump motors (September 28, 2023)
- eCFR — 10 CFR 431.485, energy conservation standards for pool pump motors
- California Energy Commission — 2025 Building Energy Efficiency Standards (Title 24, Part 6), §110.4 and §150.0(p)
- California Energy Commission — 2025 Energy Code (permit applications from January 1, 2026)
- U.S. DOE Energy Saver — Solar Swimming Pool Heaters (archived March 2025)
- U.S. DOE Energy Saver — Swimming Pool Covers (archived March 2025)
- SCE — Time-of-Use residential rate plans (TOU-D-PRIME prices)
- SCE — Solar Billing Plan (Energy Export Credit values)
- LADWP — Service Rider NEM, Net Energy Metering
- LADWP — Consumer Rebate Program (variable-speed pool pumps)
- PVGIS (European Commission JRC) — PV performance tool
- IRS — Residential Clean Energy Credit
Get a real number for your pool and solar
Tell us your pump (or the watts it shows), your roof and a recent bill, and we’ll size solar to the pool’s real kWh — and check your panel if a heat-pump heater is coming. Call +1-323-844-7777.
Get a free estimatePrepared by Cali Energy, October 1, 2026. This article is for general educational purposes only and is not legal, tax, financial, engineering, or utility advice. Rates, incentives, codes, permit requirements, equipment specifications, prices, and program terms may change; figures and timelines are estimates, not guarantees. Confirm current requirements with the applicable utility, AHJ, program administrator, manufacturer, or a licensed professional. See our Content Disclaimer. Cali Energy · 19201 Parthenia St, Unit E, Northridge, CA 91324 · CSLB #1032379 (B, C-10, C-39)