The eastern Gulf of Mexico water temperature ranged from 52°F – 64°F this morning, well below the January historical average of 66°F. An unheated, uncovered pool in Southwest Florida will likely be in the 50’s today. Unfortunately, heating your pool with solar will probably not make a drastic increase in the pool temperature, particularly if you do not cover your pool. Nighttime air temperatures in the 30’s cause the surface to lose heat at an alarming rate. Daytime air temperatures in the 50’s and 60’s don’t help matters much.
Solar pool heat with a cover will keep your pool well into the 60’s and possibly at 70 degrees on days like this. It’s unlikely that you will want to use your pool on a cold day like today anyway, but its important to keep your pool temperature up so that temperatures can recover as soon as we get some nicer weather. The weekend forecast shows Sunday, January 8th, 2012 being a high of 79°F. You may want to get in the pool! Keep in mind that water temperatures will lag air temperatures significantly. Just because the air temperature will reach 79 degrees, don’t expect unheated pool water to get that warm!
Alas, despite the wonders of solar pool heating, we can’t work miracles. We are entering the very short period of the year in Southwest Florida where swimming without heating is not possible, or at least comfortable for most people on most days.
What about running a electric heat pump on days like this? The short answer is, don’t bother! Heat pumps work by collecting ambient heat from the surrounding air and transferring that heat to the pool water. When air temperatures are below 65 degrees, heat pumps are mostly or completely ineffective because there is little ambient heat available. You will be increasing your utility bill needlessly. On the other hand, if temperatures do get a little warmer, using a solar pool heating system and cover in conjunction with a heat pump can be an effective way to get pool water to a comfortable level quickly. The bottom line is that heat pumps are expensive to operate with or without solar pool heating, so consider whether you really want to swim this time of year.
You can get current Gulf temperatures at NOAA here: http://www.solarsouthwestflorida.com/gulf-of-mexico-temperature-naples-fl/