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Solar Panel for Pool Pump Calculator

Enter your pump HP, run schedule, and location — get panels needed, annual electricity savings, and payback period.

Pool pump details
hrs/day
W
$/kWh
Solar system for your pool pump
5 × 400W panels (2.00 kW system)
Pump draw1,119 W
Daily kWh usage8.95 kWh/day
Monthly grid cost$40.82/mo
Annual electricity cost$490/yr
Annual solar savings$490/yr
Est. system cost$7,300
Payback period14.9 yrs
Monthly: grid vs solar (amortized)$41 vs $41/mo
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How to Use This Calculator

Select your pump HP and run schedule

Find the horsepower rating on your pool pump's motor nameplate — it's stamped on the label. Most residential pools use 0.75–2 HP single-speed pumps. If you have a variable speed pump (VSP), toggle that option: VSPs run at low RPM most of the time and consume roughly 40% of their rated wattage on average, which dramatically changes the solar sizing.

Enter location, panel wattage, and system type

Location determines peak sun hours — the key input for solar sizing. Panel wattage defaults to 400W (standard residential). Choose grid-tied if you're connected to utility power (most pool owners are). Choose off-grid only if you need the pump to run independently from the grid, which requires a battery bank for cloudy days.

Read the results

The calculator shows system size in kW, panel count, annual electricity savings, estimated system cost, and payback period. For off-grid setups it also shows the battery size needed for 2 days of autonomy. The monthly comparison row shows your current grid cost vs. the amortized monthly solar cost — once payback is reached, solar electricity is essentially free.

The Formula

Effective Watts = Pump Watts × (0.40 if variable speed, else 1.0) Daily kWh = Effective Watts × Run Hours ÷ 1000 Annual kWh = Daily kWh × 365 System Watts = Daily kWh × 1000 ÷ Peak Sun Hours ÷ 0.80 Panel Count = System Watts ÷ Panel Wattage (round up) Annual Savings = Annual kWh × Electricity Rate Battery kWh (off-grid) = Daily kWh × 2 days ÷ 0.80 DoD Payback Years = System Cost ÷ Annual Savings

The 0.80 system efficiency accounts for inverter losses, wiring losses, and real-world soiling. The 0.40 factor for variable speed pumps reflects that VSPs spend most of their operating time at 30-50% RPM, which cuts power consumption to roughly 10-40% of rated wattage (cubic law). Off-grid battery sizing uses 2 days of autonomy at 80% depth of discharge — a conservative design that protects battery life.

Example

The Garcias — Medium pool in Los Angeles

The Garcia family has a 1.5 HP single-speed pump running 8 hours per day in Los Angeles. They pay $0.15/kWh and want to know the solar cost to eliminate their pump's electricity bill.

Pump1.5 HP single-speed (1,119W)
Run schedule8 hrs/day
LocationLos Angeles, CA (5.6 PSH)
Rate$0.15/kWh

Result

Daily usage8.95 kWh/day
Annual cost$490/yr
Panels needed5 × 400W panels (2.0 kW)
Annual savings$490/yr
Est. system cost~$7,300
Payback~14.9 years

Alternatively, if the Garcias upgrade to a 2 HP variable speed pump ($900) and run it 10 hours at low speed, the effective draw drops to ~597W — cutting annual electricity use by more than half and reducing payback significantly. Variable speed pumps often deliver a better ROI than solar alone for pool pumps.

FAQ

Yes — solar panels can directly power a pool pump motor, but the approach matters. The simplest method is a grid-tied solar system that offsets your pump's electricity via net metering — you generate solar during the day, export it to the grid, and draw from the grid when the pump runs. A second option is a DC solar pump that runs directly from solar panels without an inverter — these are common for agricultural water pumping and can be used for pool circulation too, though they require a specially designed DC pump motor.
For most pool owners, yes — upgrade to a VSP first. A variable speed pump ($700-1,200 installed) reduces energy consumption by 60-80% vs a single-speed pump. The payback is typically 1-3 years. Once you have a VSP, the remaining solar requirement is much smaller and cheaper. Solar and VSP together often cost less than solar alone on a single-speed pump, because you need fewer panels.
A typical 1.5 HP single-speed pump running 8 hours per day uses about 270 kWh/month — around $40/month at the US average rate. A 2 HP pump running 10 hours uses roughly 447 kWh/month. Variable speed pumps running 10-12 hours at low speed use just 70-150 kWh/month for the same filtration. Pool pumps are often the second-largest electricity user in a home after air conditioning.
This calculator sizes solar PV panels to power the pool pump motor — the electric motor that circulates water through the filter. A solar pool heater calculator sizes solar thermal collectors to heat the pool water — a completely different technology using black plastic panels that absorb heat directly. Pool pumps run year-round; solar heaters are typically used to extend the swimming season by 2-4 months.
A 1 HP single-speed pump (746W) running 8 hours per day uses 5.97 kWh/day. In Los Angeles (5.6 PSH) with a 0.80 system efficiency, you need: 5.97 × 1000 ÷ 5.6 ÷ 0.80 = 1,332W ÷ 400W = 4 panels. In Phoenix (6.5 PSH) you'd need 3 panels; in Seattle (3.6 PSH) you'd need 5-6 panels. Use the calculator above to get an exact count for your location.

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<iframe src="https://solarsizecalculator.com/solar-pool-pump-calculator"
  width="100%" height="620" frameborder="0"
  title="Solar Pool Pump Calculator"></iframe>