Pool swim season in Lake Mary, FL
Swim season in Lake Mary without a heater, and with one
An unheated pool in Lake Mary reaches 78°F in Jun to Oct, about 5 months a year. The air allows up to 12 swimmable months with a heater (all year).
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Heater options for a Lake Mary pool, side by side
| Option | Months | Swimmable | Energy/yr | All-in/yr |
|---|---|---|---|---|
| No heater | 5 | Jun to Oct | $0 | $0 |
| Solar cover only | 8 | Apr to Nov | $0 | $50 |
| Solar panels + cover | 9 | Mar to Nov | $0 | $283 |
| Heat pump + cover | 12 | all year | $402 | $952 |
| Gas heater + cover | 12 | all year | $1,301 | $1,726 |
For a 450 sq ft pool held at 80°F, at FL prices of 15.3¢/kWh electricity and $25/Mcf gas. All-in spreads the purchase over the equipment's life.
The cheapest way to the full season in Lake Mary
Heat pump + cover: 12 of 12 possible months for about $952 a year all-in, which works out near $136 for each month it adds.
Before you pay for any heater, buy a solar cover: on its own it adds 3 months here for about $50 a year (why a cover comes first). If you get quotes, ask for a heat pump sized to your pool's surface area; here it beats gas all-in (heat pump or gas).
Weather station: Sanford, 5.1 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Lake Mary month by month: air, sun and pool water
| Month | Air high | Air avg | Sun kWh/m²/day | Water, unheated | Water, covered | Heat pump $ | Gas $ |
|---|---|---|---|---|---|---|---|
| Jan | 70° | 60° | 3.5 | 62° | 68° | $119 | $368 |
| Feb | 73° | 62° | 4.1 | 62° | 68° | $111 | $356 |
| Mar | 77° | 66° | 5.2 | 67° | 73° | $65 | $222 |
| Apr | 82° | 72° | 6.1 | 72° | 78° | $16 | $57 |
| May | 87° | 77° | 6.5 | 78° | 84° | – | – |
| Jun | 90° | 81° | 5.8 | 82° | 88° | – | – |
| Jul | 92° | 83° | 5.7 | 85° | 91° | – | – |
| Aug | 92° | 83° | 5.4 | 85° | 91° | – | – |
| Sep | 89° | 81° | 4.9 | 84° | 90° | – | – |
| Oct | 84° | 76° | 4.4 | 80° | 86° | – | – |
| Nov | 77° | 68° | 3.6 | 72° | 78° | $13 | $46 |
| Dec | 72° | 63° | 3.1 | 66° | 72° | $78 | $252 |
Heating costs most in Jan (about $119 with a heat pump, $368 with gas). Sunshine peaks in May at 6.5 kWh/m²/day (NASA satellite data, 33.1 km grid cell). Highlighted months are swimmable with no heater.
How Lake Mary compares with nearby cities
Lake Mary ranks 122 of 173 Florida cities for unheated swim months; Longwood, Winter Springs, Casselberry nearby get a longer season without a heater.
| City | Distance | Unheated months | Heat pump months | Heat pump $/yr |
|---|---|---|---|---|
| Longwood, FL | 4 mi | 6 | 12 | $366 |
| Sanford, FL | 4 mi | 5 | 12 | $402 |
| Winter Springs, FL | 6 mi | 6 | 12 | $366 |
| Casselberry, FL | 7 mi | 6 | 12 | $312 |
| Altamonte Springs, FL | 8 mi | 6 | 12 | $312 |
| DeBary, FL | 8 mi | 5 | 12 | $402 |