Pool heater


Active member
Dec 12, 2013
San Antonio, TX
I am looking to install a pool heater for the cooler months here in san antonio. I am looking to get any feed back on the best way to heat a pool. Hydro-solor using panels that mount on the roof in which water flows through to heat the water or install a gas heater. Any information would be appreciated.


TFP Expert
Platinum Supporter
LifeTime Supporter
Moderator Emeritus
Aug 10, 2012
FL panhandle
Solar panels are great. And you can run them at night to cool the pool too. A thin, cheap solar cover is the biggest bang for your buck though. If you don't have one try that first. I use an 8mil clear and it makes a big difference in retaining heat over night.


TFP Expert
Platinum Supporter
May 23, 2015
Tucson, AZ
Pool Size
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Have you tried just using a solar cover first to see what that gets you?

Honestly all the heating options have their pro & cons. There isn't one solution that's best. A gas heater heats fast but costs quite a bit in terms of installation and operation. Roof top solar is free heat but you have to run your pumps a lot longer than you normally do. I have gas but only use it for spot heating. It's too costly to run all the time to maintain a specific temperature.


Well-known member
Apr 3, 2015
New York
I use natural gas. It's a significant upfront cost (>2k for heater plus 1k for plumber to run line, more to dig if trenching is needed). This is a tough pill to swallow but I did it while building my pool so it was a cost I was expecting and that made it easier. To run it in my area is less than $3 per day and I keep it at 84 minimum (often turn it to 86 for weekends). Well worth it to me especially considering there is one bill per year that is $90 max more because of the heater. The other bills I get when using it are less than that. Know you have costs down the road if you roof mount things and if it's cloudy for a week you can't heat the pool. As joyfulnoise said all have pros and cons.


TFP Expert
LifeTime Supporter
Mar 1, 2012
North Georgia
I have a heat pump which runs on electricity and works the same way that your condensing unit for your A/C works. I believe that they have models which also cool and I wished I'd paid extra for one of them but that is a different story.

My heat pump is good for heating my pool (shallow and covered all of the time) up to the high 80's to low 90's depending on weather conditions. It is most effective at heating when temperatures are on in the mid 70's or higher.

Here is how a typical week would look for me. Day times highs in the low 80's, lows in the high 50's low 60's. I'd set the pump to run from 10am until 7pm and adjust heat pump to desired temp, for me that would be 91. The morning temp would be 82ish and by swim time at 5:30 pool would be 91. Next morning temp back down to 82. This is assuming my pool has been warm, if i'm starting from like 70 degrees it would take several days (like in instance of a warm spell in late october). I've played around with letting it run 24/7 to cut back on the overnight drop and basically as the outside temp starts getting 60 or below it is no longer effective at cooling.

My heat pump heats the water up about 9 degrees as measured at the returns. The air blowing out of my heat pump has about a 12 degree drop.

I cannot heat my pool up for 1 day in the middle of winter for instance. I MUST have warm outside weather for it to operate effectively or at all. Depending on size of heat pump, volume of water, pool insulation capacity, cover factor and sunlight I'be seen up to a 15 degree increase over what my water would be at 5:30 pm on any given night in late spring or early fall. Your millage will vary.

I initially wanted solar panels and have a great spot for them which we turned into a garden. My wife wouldn't go for it because guests would have walked by them....we didn't want them mounted on the roof.

Was it the best choice for us? I'm not sure. I'd like to heat it up in the middle of winter ONCE but can't. However everytime we know we are gonna have a week in October/November or March or April where the daytime highs will be in the low 70's i turn it on and heat it as high as it will go and the kids have a blast. If it gets to 90 i'll join in. 90 degrees on a Mid 50's night is something else to experience I'll tell you that. We've gotten to heat it up for Thanksgiving several times and really enjoyed it. I guess like all things, ideally you'd have all three......


TFP Expert
LifeTime Supporter
Apr 27, 2012
Grand Rapids, MI
Gjcon, I'm in Michigan, so I probably wouldn't even use my pool without a heater ;)

I'm weighing in because I just replaced my gas heater of 15 years and will give you some tips if you decide that route suits. In your clime, you might enjoy a heat pump (depending on your electrical cost) or solar.

First off, gas is fastest in shoulder seasons here. We heat to a constant and then leave it run. At 88 degrees, that means the gas bill (in Mich anyway) is roughly equivalent to our winter boiler heat cost, a bit higher in a cold May or October. But we swim a lot at night (work long days) and i swim then again around 6 am or 7, and we have a footprint that makes us not want a cover, so for us its worth it.

We've found it's cheaper to just turn it on and leave it than constantly just bringing it up...small changes instead of large changes.

Now, the reason I was posting was to save you on purchase and installation. If buying gas, you need to figure out the biggest degree differential you'd have in shoulder season (eg mine is more than 30) to size the btus for your pool maint temp. In your clime, this isn't likely as important. You also need to figure out how many BTUs you might already be using of you line, and size your line right so that you'd never starve the heater. Post back if you decide to go this route DIY and I'll dig up the way to make the calcs -- I got em from an engineering site.

In my case that added up to 266 btus (if I went bigger, I'd have had to upgrade my gas meter to 1million btus and I didn't want to.)

I wanted a trouble-free heater without complexity in electronics, as less is more I find. A few people here directed me to the Raypavk with cupronickel heat exchanger (I'm swg and copper doesn't hold up as well). The comment from repair guys was they rarely need to work on them, and when they do, they're simpler to fix.

So the pool stealer quoted me $3,100 plus installation, which he subs, for this unit (replacement on same line, interior duct work already done etc.).

I instead went to Swimming Pool Supplies, Pool Safety Cover, Swimming Pool Covers, Swimming Pool Pumps, Pool Pump Parts - INYOPools.com
(the owner is a member of TFP) and got the 266btu Raypak for $1600 shipped. I then paid an installer to install, install a zinc anode, adjust vent work, do gas line, electric and plumbing for $450 - which included the cost of the inline zinc anode (hydro tools).

So i was done and swimming again for a grand less than pool stealer wanted for the unit alone ;)


LifeTime Supporter
Aug 18, 2014
Amelia Island, FL
You and I are approximately the same latitude along I10, although you lack a beach. :D

We have hydro-solar for heating and it works EXCEPTIONALLY well, especially if you have some automation to decide if/when to heat the pool based upon current water temp, current solar temp, desired water temp, etc. my wife likes WARM water and we consistently run about 86 degrees without any cover for 8-9 months per year. If we used the solar cover we could probably hit 86 year round, but we just don't swim much in Dec, Jan and Feb.

We also have propane heater, but only use that for the spa. I would not recommend gas for the pool in our market due to gas prices. A heat pump will work well, but it's prime season is likely to be only May - Oct, which isn't enough for our family.

If you can do solar, it's a no-brainier for you in SA.