How many solar panels to run a pool pump?
A single-speed pump drawing 1,900 W at the plug (an example — a 1.5 hp motor is 1,119 W of shaft power, and the input is higher) uses about 16,889 Wh a day for 8 daytime hours through an inverter — about 4,364 W of panels, 11 panels of 400 W, at 4.5 peak sun hours.
How to work it out
- 1,900 W × 8 h ÷ 90% inverter = 16,889 Wh a day
- 0% through a battery at 92% round trip → 16,889 Wh from the panels
- ÷ (4.5 sun h × 86%) = 4,364 W → 11 panels of 400 W
ENERGY STAR calls the pool pump one of a home’s largest energy users. Because it can run whenever the sun shines, it needs little battery energy — but it still needs a battery-based inverter or a dedicated solar pump drive to run; a grid-tied inverter can’t power it on its own.
Adjust for your project
More options: From battery · Losses
- Solar array needed
- 4,364 W
- Energy per day (from the system)
- 16,889 Wh
- Figures used
- 1,900 W × 8 h a day (typical)
- A 1.5 hp motor is 1,119 W of shaft power (746 W per hp); the electrical input is higher. 1,900 W is only an example input — use amps × volts from your pump’s label. ENERGY STAR: half speed uses about one-eighth the energy.
- 1,900 W is an example input, not your pump. Read the label (amps × volts). A variable-speed pump at lower speed for longer hours can cut the energy dramatically.
- Even with almost nothing from a battery, a motor load needs a battery-based (off-grid or hybrid) inverter, or a dedicated solar pump drive. A grid-tied inverter can’t run loads on its own — it shuts down when the grid does.
Panels for each appliance at the sun hours above
| Appliance | Energy per day (from the system) | Solar array needed | Panels |
|---|---|---|---|
| Refrigerator (household) | 1,778 Wh | 459 W | 2 panels |
| Chest or upright freezer | 1,333 Wh | 345 W | 1 panel |
| CPAP (no heated humidifier) | 533 Wh | 138 W | 1 panel |
| Window AC, 10,000 BTU | 8,889 Wh | 2,297 W | 6 panels |
| Mini-split, 12,000 BTU | 10,667 Wh | 2,756 W | 7 panels |
| Pool pump (example: 1,900 W input) | 16,889 Wh | 4,364 W | 11 panels |
What to know about running a pool pump on solar
- Shaft horsepower isn’t electrical watts. 1 hp is 746 W at the shaft; the motor’s electrical input is higher because motors aren’t 100% efficient. This page uses 1,900 W as an example input; multiply your label’s amps by its volts and enter that as the watts.
- Variable speed changes everything. ENERGY STAR notes that running a pump at half speed uses about one-eighth as much energy. A variable-speed pump running longer at low speed can cut this page’s figure by more than half.
- Run it in the middle of the day. Energy used while the sun shines barely touches the battery, so the bank can stay small — but the inverter must be a battery-based or hybrid model (or a solar pump drive), sized for the motor’s start.
- Grid-tied is a common route. Many pool owners add panels to a grid-tied system sized on yearly kWh rather than a dedicated off-grid pump system — see how many solar panels for 2000 kWh per month.
Other big motor loads: how many solar panels to run a mini split and what size generator to run a well pump. For the pump’s running cost on the grid, enter its watts in the electricity cost calculator.
Different size? Use the full Solar Panels for One Appliance.
What you’ll need
- 400 W residential-size solar panelPremium price
Fewer, larger panels for a cabin, shed or ground mount. Their higher voltage usually means an MPPT controller.
See options on Amazon (opens in a new tab) - Plug-in electricity usage monitorBudget price
Plugs in between the wall and a 120 V appliance and shows real watts and kWh over a day — the honest way to fill in a load list, especially for fridges that cycle on and off.
See options on Amazon (opens in a new tab)
As an Amazon Associate we earn from qualifying purchases. Links to products are affiliate links — they cost you nothing extra and help keep these calculators free.
Frequently asked questions
How many solar panels to run a pool pump drawing 1,200 W?
About 2,756 W — 7 panels of 400 W — for 8 daytime hours.
How many solar panels to run a pool pump 4 hours a day?
About 2,182 W — 6 panels of 400 W — at the same 1,900 W example input.
Other common sizes
- How many solar panels to run a refrigerator — 2 × 400 W panels (479 W) plus about 87 Ah of battery
- How many solar panels to run a mini split — 8 × 400 W panels (2,816 W)
Sources
- Champion Power Equipment — Generator Wattage Chart (opens in a new tab) — Typical running and starting watts for household, RV and job-site appliances (a manufacturer’s planning chart — your nameplate wins).
- Virginia Cooperative Extension, BSE-301: Estimating Appliance and Home Electronic Energy Use (2020) (opens in a new tab) — Wattage × hours ÷ 1,000 = kWh per day; watts = amps × volts when only amps are listed; a refrigerator runs at full wattage about a third of the time; typical nameplate wattages.
- ENERGY STAR — Pool pumps (opens in a new tab) — Running a pool pump at half speed uses about one-eighth as much energy.
- Victron Energy — Energy Unlimited (book) (opens in a new tab) — Lead-acid charge efficiency 80–95% (85% suggested as a starting value); battery energy efficiency about 75% for full cycles, about 89% in partial state of charge; inverter efficiencies above 90%.
- Victron Energy — Lithium Battery Smart manual, technical data (opens in a new tab) — LiFePO4 12.8 V: cycle life 2,500 at 80% DoD, 3,000 at 70%, 5,000 at 50% (to 80% of capacity); 92% round-trip efficiency; 12.8 V 100 Ah: recommended continuous discharge ≤100 A (1C), maximum 200 A; capacity about 20% lower at 0 °C; charge only between +5 °C and +50 °C.
- National Laboratory of the Rockies (formerly NREL) — PVWatts® Calculator (opens in a new tab) — Look up the solar resource (peak sun hours) and yearly output for your own address; default system losses 14%.