Heater question - only occasional use

[JJS Houston]

We have an approximately 40k gallon pool in the Houston area. What I am trying to find help with is deciding on what size pool heater (must be an electric heat pump type since no access to natural gas and do not want to incur the cost of a large propane install) for a very specific use. I ONLY want the heater to help warm the pool early in the season to take advantage of warm/hot days where the pool may not have had a chance to come up to a comfortable temperature. Also, maybe extend into the fall a bit. I do not need it to heat the pool during the winter and during the summer months, the air temperature in Houston is more than enough to keep it warm. I would like to find a solution as cost effective as possible and have no problem if a smaller unit may take a day or two to accomplish the task. How small a unit can I go to achieve the desired result?


Thank you!!

 

[Dirk]

Solar panels make my pool more comfortable sooner and later around swim season. Not by a huge amount, but they are often the difference between me wanting to get in or not. That may not be enough for your mission, but it's something to consider. I think the install costs are comparable, but even if not, once installed, the cost to heat my pool is near zero.* I would be running the pump anyway for my salt water generator, so pumping it through the panels adds little to the cost of that. They're guaranteed for 12 years, and I expect to get at least 20 years out of them.

I installed mine myself, so a $10K estimate for them to do it turned into only about $3K. I know you can't get a heat pump for that!

The company that supplied the materials was all set up to install all sorts of heating equipment and solar panels. So I might suggest you find one and have them give you some estimates. They'll have computer software that can project running cost scenarios along with install costs that might help you decide.

* Actually, that was before my PV panels went it. Now, my pool heating costs are zero, because of my PV solar system. Same company installed those. So when they were estimating the PV panels, their software was building me virtual systems that also included a heat pump. They provide projections for costs 20 years out, for multiple scenarios. More to the point, if you don't already have PV, that might also be something to consider. Electricity is only going to get more and more expensive. My system is in the black now, having paid for itself, so I literally pay nothing to heat my pool. That can be true with a heat pump, too (just takes more years to break even).

That all said, I don't know how any of that info might apply in Texas.

 

[1poolman1]

We have an approximately 40k gallon pool in the Houston area. What I am trying to find help with is deciding on what size pool heater (must be an electric heat pump type since no access to natural gas and do not want to incur the cost of a large propane install) for a very specific use. I ONLY want the heater to help warm the pool early in the season to take advantage of warm/hot days where the pool may not have had a chance to come up to a comfortable temperature. Also, maybe extend into the fall a bit. I do not need it to heat the pool during the winter and during the summer months, the air temperature in Houston is more than enough to keep it warm. I would like to find a solution as cost effective as possible and have no problem if a smaller unit may take a day or two to accomplish the task. How small a unit can I go to achieve the desired result?


Thank you!!

You always want to get the largest BTU-rated heater of any type if possible, even solar panels if you have the room.
Everyone for whom I ever installed a smaller unit than I recommended was disappointed in the performance.
One even wanted to "trade in" his "slightly used" new heater two weeks after the install. Told him from the beginning that would never be an option.

 

[gkw4815]

I'd get the biggest BTU heat pump that you can. 40k gallons is a very large pool, a heat pump will likely take awhile to heat the pool + may struggle to keep up during weather like what we're seeing now, with mild days but overnight lows in the lower 50s. Do you have a solar cover for the pool, or could you get one?

 

[mmcwhorter]

We had twelve 8x12 solar panels in St Pete FL, the last home we lived in. 10 years ago. Man, it worked great. Using an automated Jandy system, I'd fire don't the spa at 2 PM in Feb,. and if we wanted to use it at 9 PM...it was all set. Brainlessly simple. Loved it. Those panels would heat the spa (2000 gallons) in about 20 minutes. As to the entire pool, it made swimming in February very comfy too. The system was automated for freeze protection to turn on, which happened often at night. I think it was a Jandy JS-4 (probably obsolete by now but I loved it).

 

[JJS Houston]

Thank you all for your input. Due to the arrangment of the yard and other considerations, solar panels are not a viable option.

With that said, I am still wondering what the minimum size heat pump would be for the scenario described. I do not want to go too large and have something that I am not fuly utiilizing.

 

[gkw4815]

Even the largest heat pumps on the market may struggle in the shoulder season with a 40k gallon pool. I wouldn't worry about "under-utilizing" one.

 

[ajw22]

With that said, I am still wondering what the minimum size heat pump would be for the scenario described. I do not want to go too large and have something that I am not fuly utiilizing.

Would you rather not fully utilize your pool because it is slow to heat or never can get to the temperature you want?

You never not fully utilize a heat pumps output. You need a 120K-140K BTU heat pump.

 

[JJS Houston]

Thank you.

Here in Houston, the air temp at the beginning of the season often gets well into the 90's before the pool gets anywhere near the 85 or so that we find comfortable, and during the summer there is NO need for a heater at all. To clarify a bit, I am 60 and my wife not far behind, no kids, and no major pool parties. Just want to find some way to heat it up for a few weeks in the spring (and a bit into the fall (but not much)) that will not break the bank for that purpose. We have no problem giving it a day or so for a lesser pump to do its thing, if it means saving a grand or more to use for other things.

 

[JJ_Tex]

If you are going to spend the $ for a heat pump, I would suggest one with a chiller function too to avoid bath water in August and September.

At least then you could maybe justify the cost since you would be using it more often and for multiple scenarios.