Heat Pump vs. Gas Heater

[TXSlater]

Hello there - We are thinking of adding a heater. Mainly to extend the season but will probably occasionally heat the pool on a random warm winter day. We live in Austin, TX. Our pool is 14 x32 and 5 feet at the deepest. Stays nice and warm in the summer months but I think would be swimmable in April and October if we had a heater. We may have a gas line close, but I'm not sure (pool equip is where original water heater was, but I'm not sure if they capped the line or just rerouted it to other side where water heater is currently). We have all Pentair equipment. Should we get something, and if so what?

 

[Homebrewale]

If you want to swim on a random warm winter day, then get a gas heater. I have a heat pump and it takes several days to raise the water temperature to swimming temperatures. We have a heat pump because my wife swims daily for exercise in the April and October months you mention. We also use a solar blanket. Heat pumps work great at maintaining a consistent temperature but gas heaters are good at raising the temperature quickly.

 

[scdaren]

but will probably occasionally heat the pool on a random warm winter day

For this kind of use, you really want a gas heater, they can heat the pool up much faster. A heat pump is great and very efficient at maintaining a nice temperature on those shoulder months to extend the season. But a heat pump is only going to heat your pool about 1 degree an hour, maybe a little more on your pool. So if you need to raise it like 15 degrees in the winter, that's going to be tough. Especially since they only really work when the ambient temp outside is over 55 degrees, and they are less efficient as they approach that, so it doesn't really work well to run it overnight. I have a heat pump (Pentair 140), and when I want to get my pool swimmable from like 60 degrees, it's a couple day project, and a whole lot of electricity. But during those spring and fall months to extend the season, it just runs a couple hours a day and between that and a solar cover, it works great.

So you really need to consider the cost of each including getting the gas or added electrical to your equipment, your relative cost of electricity vs natural gas, the cost of the gas heater vs the heat pump, and how much you want to be able to use it for a random winter day.