Pool swim season in Johnson City, TN
Swim season in Johnson City without a heater, and with one
An unheated pool in Johnson City never reaches 78°F in a normal year. It peaks around 77°F in Aug. The air allows up to 6 swimmable months with a heater (May to Oct).
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What each heater buys you in Johnson City
| 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 | 6 | May to Oct | $224 | $774 |
| Gas heater + cover | 6 | May to Oct | $369 | $794 |
For a 450 sq ft pool held at 80°F, at TN prices of 13.8¢/kWh electricity and $12/Mcf gas. All-in spreads the purchase over the equipment's life.
The cheapest way to the full season in Johnson City
Heat pump + cover: 6 of 6 possible months for about $774 a year all-in, which works out near $129 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: Elizabethton, 7.4 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Johnson City 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 | 46° | 36° | 2.2 | 37° | 43° | – | – |
| Feb | 50° | 39° | 2.8 | 37° | 43° | – | – |
| Mar | 59° | 47° | 4.0 | 44° | 50° | – | – |
| Apr | 69° | 56° | 5.2 | 53° | 59° | – | – |
| May | 77° | 64° | 5.8 | 63° | 69° | $92 | $156 |
| Jun | 83° | 71° | 6.2 | 71° | 77° | $23 | $43 |
| Jul | 86° | 75° | 5.9 | 76° | 82° | – | – |
| Aug | 85° | 74° | 5.5 | 77° | 83° | – | – |
| Sep | 80° | 68° | 4.7 | 73° | 79° | $11 | $20 |
| Oct | 70° | 57° | 3.6 | 63° | 69° | $98 | $150 |
| Nov | 59° | 46° | 2.7 | 51° | 57° | – | – |
| Dec | 50° | 39° | 2.0 | 42° | 48° | – | – |
Heating costs most in Oct (about $98 with a heat pump, $150 with gas). Sunshine peaks in Jun at 6.2 kWh/m²/day (NASA satellite data, 20.5 km grid cell). Highlighted months are swimmable with no heater.
How Johnson City compares with nearby cities
Johnson City ranks 63 of 65 Tennessee cities for unheated swim months; Kingsport nearby gets a longer season without a heater.
| City | Distance | Unheated months | Heat pump months | Heat pump $/yr |
|---|---|---|---|---|
| Elizabethton, TN | 8 mi | 0 | 6 | $224 |
| Kingsport, TN | 15 mi | 1 | 7 | $331 |
| Bristol, TN | 17 mi | 0 | 6 | $201 |
| Bristol, VA | 23 mi | 0 | 5 | $190 |
| Greeneville, TN | 27 mi | 0 | 6 | $193 |
| Boone, NC | 41 mi | 0 | 4 | $230 |