Quick answer
A pool with an old single-speed pump can use about 2,080 kWh in an Illinois season, which takes roughly 1.7 kW of extra solar; a variable-speed pump cuts that to about 620 kWh. A hot tub uses about 2,190 kWh a year. Pool loads peak in summer, exactly when solar produces most, which makes them a good fit.
How much electricity does a pool or hot tub use?
| Load | Yearly use | Extra solar | Extra panels |
|---|---|---|---|
| Single-speed pool pump | About 2,080 kWh | About 1.7 kW | 5 |
| Variable-speed pool pump | About 620 kWh | About 0.5 kW | 2 |
| Hot tub, year-round | About 2,190 kWh | About 1.8 kW | 5 |
The pump figures assume 8 hours a day for about 130 days, from mid-May through September, at the example wattages Pacific Northwest National Laboratory gives for a 1.5-horsepower pump at full speed (about 2,000 watts) and at reduced speed (about 593 watts). The hot tub figure is the roughly 6 kWh a day median that Jacuzzi reports from its users. Your pool's size, run time and equipment change these numbers, so use your own bills when you can.
Should I replace my pool pump before going solar?
If it's an old single-speed pump, probably. ENERGY STAR says certified variable-speed pumps use about 60% less energy than old single-speed pumps, because running at half speed takes about an eighth of the power. That can shrink the solar you need by a few panels.
Since July 2021, federal efficiency rules for pool pumps have effectively pushed most new in-ground pumps to variable speed, so a replacement will likely be variable-speed anyway. If your pump is near the end of its life, replace it first and size solar for the new one.
Which pool heater works best with solar?
| Heater | How it works | Notes for Illinois |
|---|---|---|
| Heat pump | Moves heat from the air into the water; COPs typically 3 to 7 | Runs on electricity, so solar can power it; most efficient above about 50°F, less so in spring and fall |
| Gas | Burns natural gas or propane | Heats fast, suits occasional use, but costs more to run over a season |
| Solar pool collectors | Circulates pool water through roof collectors | About $2,500 to $4,000 installed, payback of 1 to 7 years per DOE; separate from solar panels |
The biggest saving is a cover. The Department of Energy says covering the pool when it's not in use can cut heating costs by 50% to 70%, because evaporation is by far the largest source of heat loss.
Do pools and hot tubs fit well with solar in Illinois?
Pools fit especially well. Pumps run during the day in the same months solar panels produce the most, so the power goes straight into the pump instead of being exported. Since 2025, Illinois credits exported solar at the supply rate only, but solar you use as it's made saves the full retail rate. Set the pump timer for midday hours to get the most from it.
Hot tubs are the opposite: they run all year and use the most in winter, when panels produce the least. Solar still offsets that use over the year, but at the lower export credit for summer production. See Illinois net metering.
How should I size solar for a home with a pool?
- 1
Use 12 months of bills
Summer bills show the pool's effect; winter bills show the hot tub's.
- 2
Fix the cheap stuff first
A variable-speed pump and a cover cut the load before you buy panels to cover it.
- 3
Add planned loads
If a heat pump pool heater or hot tub is coming, include it now; adding panels later costs more per watt.
- 4
Check the price
A bigger system should cost less per watt. Check any quote with the quote checker.
See solar with a $250+ electric bill and solar for large homes for sizing larger systems.
Sources
- PNNL Building America Solution Center: Variable-speed pool pumps
- ENERGY STAR: Pool pumps fact sheet (2023)
- Jandy: DOE dedicated-purpose pool pump regulations
- U.S. Department of Energy: Heat pump swimming pool heaters
- U.S. Department of Energy: Gas swimming pool heaters
- U.S. Department of Energy: Solar swimming pool heaters
- U.S. Department of Energy: Swimming pool covers
- Jacuzzi: How much electricity does a hot tub use?
- Illinois Shines: FAQs related to changes in net metering in Illinois
- NREL PVWatts Calculator
This guide is general information, not tax, legal or financial advice. Incentive programs change, so confirm current terms with your installer, your utility and a tax professional.