Pool swim season in Alpena, MI
Swim season in Alpena without a heater, and with one
An unheated pool in Alpena never reaches 78°F in a normal year. It peaks around 70°F in Aug. The air allows up to 3 swimmable months with a heater (Jun to Aug).
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What each heater buys you in Alpena
| Option | Months | Swimmable | Energy/yr | All-in/yr |
|---|---|---|---|---|
| No heater | 0 | no month | $0 | $0 |
| Solar cover only | 0 | no month | $0 | $50 |
| Solar panels + cover | 2 | Jul to Aug | $0 | $283 |
| Heat pump + cover | 3 | Jun to Aug | $298 | $848 |
| Gas heater + cover | 3 | Jun to Aug | $298 | $723 |
For a 450 sq ft pool held at 80°F, at MI prices of 21.7¢/kWh electricity and $11/Mcf gas. All-in spreads the purchase over the equipment's life.
The cheapest way to the full season in Alpena
Solar panels + cover: 2 of 3 possible months for about $283 a year all-in, which works out near $142 for each month it adds.
A solar cover alone adds no swim months here, so if you want a longer season you need a heater (why); still use one at night to hold the heat you pay for. 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: Alpena Water Treatment Plant, 1.2 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Alpena 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 | 27° | 20° | 1.2 | 22° | 28° | – | – |
| Feb | 29° | 21° | 2.1 | 20° | 26° | – | – |
| Mar | 37° | 29° | 3.6 | 25° | 31° | – | – |
| Apr | 48° | 40° | 4.6 | 36° | 42° | – | – |
| May | 61° | 52° | 5.5 | 49° | 55° | – | – |
| Jun | 71° | 62° | 6.0 | 60° | 66° | $180 | $175 |
| Jul | 77° | 68° | 6.0 | 68° | 74° | $68 | $71 |
| Aug | 76° | 67° | 5.1 | 70° | 76° | $50 | $52 |
| Sep | 69° | 60° | 4.0 | 65° | 71° | – | – |
| Oct | 56° | 48° | 2.4 | 53° | 59° | – | – |
| Nov | 43° | 36° | 1.3 | 40° | 46° | – | – |
| Dec | 33° | 27° | 0.9 | 30° | 36° | – | – |
Heating costs most in Jun (about $180 with a heat pump, $175 with gas). Sunshine peaks in Jul at 6.0 kWh/m²/day (NASA satellite data, 47.5 km grid cell). Highlighted months are swimmable with no heater.
How Alpena compares with nearby cities
Alpena ranks 87 of 90 Michigan cities for unheated swim months, and no nearby city gets a longer unheated season.
| City | Distance | Unheated months | Heat pump months | Heat pump $/yr |
|---|---|---|---|---|
| Bay City, MI | 105 mi | 0 | 4 | $201 |
| Sault Ste. Marie, MI | 107 mi | 0 | 3 | $359 |
| Midland, MI | 107 mi | 0 | 4 | $205 |
| Traverse City, MI | 108 mi | 0 | 4 | $283 |
| Cadillac, MI | 113 mi | 0 | 4 | $382 |
| Saginaw, MI | 117 mi | 0 | 4 | $172 |