Pool swim season in Millville, NJ
Swim season in Millville without a heater, and with one
An unheated pool in Millville never reaches 78°F in a normal year. It peaks around 78°F in Aug. The air allows up to 5 swimmable months with a heater (May to Sep).
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Heater options for a Millville pool, side by side
| Option | Months | Swimmable | Energy/yr | All-in/yr |
|---|---|---|---|---|
| No heater | 0 | no month | $0 | $0 |
| Solar cover only | 3 | Jul to Sep | $0 | $50 |
| Solar panels + cover | 4 | Jun to Sep | $0 | $283 |
| Heat pump + cover | 5 | May to Sep | $291 | $841 |
| Gas heater + cover | 5 | May to Sep | $341 | $766 |
For a 450 sq ft pool held at 80°F, at NJ prices of 24.1¢/kWh electricity and $14/Mcf gas. All-in spreads the purchase over the equipment's life.
The cheapest way to the full season in Millville
Solar panels + cover: 4 of 5 possible months for about $283 a year all-in, which works out near $71 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 gas as well as a heat pump: once the purchase price is counted, gas comes out cheaper all-in here (heat pump or gas).
Weather station: Millville Municipal Airport, 2.1 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Millville 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 | 42° | 33° | 2.0 | 34° | 40° | – | – |
| Feb | 45° | 35° | 2.9 | 34° | 40° | – | – |
| Mar | 52° | 42° | 3.8 | 39° | 45° | – | – |
| Apr | 64° | 52° | 5.0 | 49° | 55° | – | – |
| May | 73° | 62° | 5.6 | 60° | 66° | $211 | $239 |
| Jun | 82° | 71° | 6.2 | 70° | 76° | $58 | $75 |
| Jul | 86° | 76° | 6.2 | 77° | 83° | – | – |
| Aug | 84° | 74° | 5.4 | 78° | 84° | – | – |
| Sep | 78° | 68° | 4.4 | 72° | 78° | $22 | $27 |
| Oct | 67° | 56° | 3.2 | 62° | 68° | – | – |
| Nov | 56° | 46° | 2.3 | 50° | 56° | – | – |
| Dec | 47° | 37° | 1.8 | 40° | 46° | – | – |
Heating costs most in May (about $211 with a heat pump, $239 with gas). Sunshine peaks in Jun at 6.2 kWh/m²/day (NASA satellite data, 40.1 km grid cell). Highlighted months are swimmable with no heater.
How Millville compares with nearby cities
Millville ranks 67 of 116 New Jersey cities for unheated swim months; Bridgeton, Glassboro, Somers Point nearby get a longer season without a heater.
| City | Distance | Unheated months | Heat pump months | Heat pump $/yr |
|---|---|---|---|---|
| Vineland, NJ | 6 mi | 0 | 5 | $293 |
| Bridgeton, NJ | 10 mi | 1 | 5 | $257 |
| Glassboro, NJ | 22 mi | 1 | 5 | $256 |
| Hammonton, NJ | 24 mi | 0 | 5 | $295 |
| Somers Point, NJ | 24 mi | 2 | 4 | $46 |
| Ocean City, NJ | 26 mi | 2 | 4 | $46 |