As inefficient electric pool heat pumps and gas pool heaters are, they have their place in heating Southwest Florida pools. It’s no problem to have both solar pool heat and a heat pump or auxiliary gas heater. In fact, the whole system can be automated with fairly simple controls and automatic valves.

Many thousands of heat pumps are installed in Florida, the result of aggressive advertising campaigns and irresponsible claims by manufacturers about how efficient heat pumps are. The fact of the matter is that heat pumps cost an arm-and-a-leg to operate. Heat pumps are important when the desired temperature is critical to attain and maintain at all times. For example, hotels, condos, and individuals with medical hydrotherapy needs often require a constant and elevated pool temperature. In these cases, the holy grail is a solar pool heater in conjunction with a heat pump.
Because gas prices are relatively high in Florida, the only reasonable application for a gas heater is in situations where raising the pool temperature quickly is required or where swimming is anticipated during cold ambient temperatures. Long-term constant heating with gas heaters is outrageously expensive.
If you choose to have a heat pump or gas heater, or you already have one installed, integrating solar pool heat is easy. An automatic controller can set the solar pool heater as the primary heat source and revert to auxiliary heating. In most cases, a solar pool heater is installed, and the auxiliary heater is only operated on-demand by the homeowner manually switching on the heater. This can be as easy as pushing a button on a controller or even using a remote control to switch on the auxiliary heater.

The AquaLink RS, Aqua Logic, and other high-end pool controllers are very capable at controlling multiple heat sources. If you already have a pool automation system, it is likely that solar pool heat and a heat pump can already be controlled from it. If not, I have been recommending the affordable Pentair SunTouch with the optional Quicktouch II Remote. Once programmed, operating the pool equipment is as simple as pressing buttons on a remote. It can work with any combination of heat sources and can even control your spa and a variable speed pump. In some cases, pool lighting and landscape lighting control can also be integrated.
Fafco Solar installed a solar pool heat system this week at a home that already had a heat pump. Adding a SunTouch controller allowed the homeowner to optimize the operation of their solar pool heater, while providing the option of supplemental heat at the press of a button if desired. This time of year, solar pool heating alone typically gets a covered pool to around 85 degrees. The grandkids were coming in town this week, and he wanted the pool to be 88 degrees. The controller allows the pool to be heated by solar if possible, then switches on the heat pump to get the last couple of degrees needed at a reasonable operating cost.
I was wondering if you have every installed a heat pump and gas heater in parallel with each other. Allowing the gas heater to be used only when turned on but the heat pump can be used to maintain the constant temperature? We live in MI and the heat pump can not pull enough heat out of the air during early/late swim seasons so we are trying to figure out how to improve our heating method in order to extend our swimming season.
I think you would want to hook this up in series, but I have an idea for you. We install solar pool heaters with heat pumps very frequently in Southwest Florida. You can automate the system to be in “Solar Priority Mode” where solar will operate when available, and then the auxiliary heater will take over. There is an option in the Pentair SunTouch controller to use “Solar as Heat Pump.” This lets you control a heat pump valve as if it were a solar pool heater. With a little logic and programming you could set it up to be completely automated based on desired temperatures.
I’ve never done it, as gas heaters are not popular here, but the concept should work.