Madwil:

You may want to review that. Heat pumps are actually far more efficient for pool heating than they are for home heating. Heat pumps got a bad rap because they were installed in areas were temperatures would go into the low 30's and high 20's in the winter (Like the Washington, DC area) and then they would kick to resistance heating. But if the heat pump is working in temperatures of 58 degrees or above, they far outstrip NG and oil for efficiency. The latest version of heat pumps are called geothermal heat pumps because they don't use the air, but instead use the natural temperature of the ground below the frost line, usually in the mid 50's, for both heating and A/C. This has been a major break-through for heat pumps' efficiency in general. Yet pool heat pumps are already "there" so to speak.

Now a pool heater here in NJ going to be running when the air temp is in the 60's, 70's, 80's or even 90's, right in its sweet spot for efficiency. Meanwhile, a NG heater is simply adding calories to water at a certain temperature, and the air temp doesn't effect the efficiency of the burning gas at all. My next door neighbor has NG and he tells me he HATES to run it--his gas bill goes, well, through the roof.

Personally, I'm a solar guy, but I have good sun on my pool. I would not personally install a NG heater in NJ. But when I did the wiring for my pool, I had the electrician run cable so I can put in a heat pump if I ever want to go that route.

However, with my parents' pool, years ago, a 13-15,000 gallon AG, I put a 20'x4' and 10'x4' set of flexible solar panels. They had poor sun coverage--only about 6 hours directly on the panels per day. Yet their pool, which for years had been a chilly 78 deg, was 84 deg all summer--nice and comfortable.

Carl