Are solar pool panels enough, or do you need a heater?
The short answer
In most of the country, solar panels plus a cover are the best value: they win in 2,564 of 3,206 cities (80%). They burn no fuel, since the existing filter pump pushes water through them, so after the purchase (about $3,500 installed, lasting about 15 years) the running cost is close to zero. What they cannot do is heat a pool when the sun is weak, so in 2,291 cities they stop short of the longest season a heater could give.
Where solar panels get the whole season
| City | Solar months | Heat pump months | Solar all-in/yr | Heat pump all-in/yr |
|---|---|---|---|---|
| Chicago, IL | 4 | 4 | $283 | $662 |
| Phoenix, AZ | 9 | 9 | $283 | $724 |
| Dallas, TX | 7 | 7 | $283 | $624 |
| Jacksonville, FL | 9 | 9 | $283 | $703 |
Where they fall short
| City | Solar months | Heat pump months | Solar all-in/yr | Heat pump all-in/yr |
|---|---|---|---|---|
| San Antonio, TX | 7 | 9 | $283 | $815 |
| Austin, TX | 7 | 9 | $283 | $794 |
| Mesa, AZ | 8 | 10 | $283 | $911 |
| Tampa, FL | 10 | 12 | $283 | $822 |
The missing months are the shoulder months, early spring and late autumn, when the air is still mild but the sun is low. If those months matter to you, a heat pump or gas heater is what buys them; if you mostly swim in summer, solar is usually enough.
Related: Start with a cover · Heat pump or gas? · When to open your pool.