Pool swim season in Martinsville, VA
Martinsville, VA: how long the pool season really is
An unheated pool in Martinsville never reaches 78°F in a normal year. It peaks around 78°F in Aug. The air allows up to 7 swimmable months with a heater (Apr to Oct).
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What each heater buys you in Martinsville
| 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 | 7 | Apr to Oct | $510 | $1,060 |
| Gas heater + cover | 7 | Apr to Oct | $929 | $1,354 |
For a 450 sq ft pool held at 80°F, at VA prices of 16.9¢/kWh electricity and $17/Mcf gas. All-in spreads the purchase over the equipment's life.
The cheapest way to the full season in Martinsville
Heat pump + cover: 7 of 7 possible months for about $1,060 a year all-in, which works out near $151 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: Martinsville Fltr Plt, 1.5 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Martinsville 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 | 48° | 36° | 2.5 | 37° | 43° | – | – |
| Feb | 52° | 39° | 3.2 | 38° | 44° | – | – |
| Mar | 60° | 46° | 4.2 | 44° | 50° | – | – |
| Apr | 71° | 56° | 5.4 | 53° | 59° | $234 | $406 |
| May | 78° | 64° | 5.8 | 63° | 69° | $113 | $221 |
| Jun | 85° | 72° | 6.3 | 71° | 77° | $24 | $52 |
| Jul | 88° | 76° | 6.0 | 77° | 83° | – | – |
| Aug | 86° | 74° | 5.4 | 78° | 84° | – | – |
| Sep | 80° | 68° | 4.5 | 72° | 78° | $15 | $31 |
| Oct | 71° | 57° | 3.6 | 63° | 69° | $124 | $219 |
| Nov | 60° | 46° | 2.8 | 51° | 57° | – | – |
| Dec | 51° | 39° | 2.2 | 42° | 48° | – | – |
Heating costs most in Apr (about $234 with a heat pump, $406 with gas). Sunshine peaks in Jun at 6.3 kWh/m²/day (NASA satellite data, 38.3 km grid cell). Highlighted months are swimmable with no heater.
How Martinsville compares with nearby cities
Martinsville ranks 25 of 39 Virginia cities for unheated swim months; Eden, Reidsville, Danville nearby get a longer season without a heater.
| City | Distance | Unheated months | Heat pump months | Heat pump $/yr |
|---|---|---|---|---|
| Eden, NC | 14 mi | 2 | 7 | $373 |
| Reidsville, NC | 26 mi | 2 | 6 | $173 |
| Danville, VA | 26 mi | 2 | 7 | $374 |
| Summerfield, NC | 34 mi | 2 | 7 | $292 |
| Greensboro, NC | 41 mi | 2 | 7 | $283 |
| Roanoke, VA | 41 mi | 2 | 6 | $195 |