Heat pump question

[Icemodeled]

Hello everyone, wanting to say a big thanks to this forum as we have had beautiful clear water since our pool was build in June.

our pool specs are in my signature below. We just had a hayward pool heater installed today 100k BTUs. wanting to swim year round(in southwest Florida) plus I have a foot injury and swimming is allowed(and encouraged) for rehab so wanting to use the pool often(4-5x a week at least) day temps here normally around 75-80 degrees and nights normally around 60s but can get colder. Pool is currently around 64 degrees. Wanting to stay minimum of 85 degrees.

my questions are:
* should we leave the pool heater running nonstop if we plan to use it 4/5 times a week or is it possibly more efficient to turn it off/on as needed? Worried about expense if running constant(since I’m guessing the pump must run non stop to - currently pump runs 9 hours a day). What would you do in our case.. leave it all running constantly or try and conserve much as possible and turn off occasionally.
* if we do try to turn it off/on and not run constant how early should we turn it on before hoping to swim? We have a fairly small pool but not to sure about this one As to how long it takes to heat up at 85.
*if we let the heater run nonstop, is it ok to let it shut off when the pump shuts off(so would run 9 hours a day) or would this not work as 9 hours a day won’t keep the pool temp steady..? just really unsure the best approach considering we would like to use it more often...(if possible without a enormous electric bill).

any advice is appreciated!

 

[ajw22]

1 BTU will raise 1 pound of water 1 degree. 9000 gallons of water is 75,000 pounds. A 100K BTU heater will raise your water by about 1 to 1.3 degrees an hour.

Given that how long you need to run your pump and heater depends on what temperature your water starts at and what you want to heat it to. Raising the water from 65 degrees to 85 degrees will take around 20 hours of run time.

You need to see if your water is 85 degrees and you don't run the heater at night how much temperature you lose. If you lose 5 degrees it can take you 4 to 5 hours of run time in the morning to get back to 85 degrees. If you are looking to swim in 85 degree water in the morning that may not work for you. If your swim is in the afternoon then the heater has time to get the water up to the desired temperature.

You need to figure out what works for you in your environment.

 

[Icemodeled]

1 BTU will raise 1 pound of water 1 degree. 9000 gallons of water is 75,000 pounds. A 100K BTU heater will raise your water by about 1 to 1.3 degrees an hour.

Given that how long you need to run your pump and heater depends on what temperature your water starts at and what you want to heat it to. Raising the water from 65 degrees to 85 degrees will take around 20 hours of run time.

You need to see if your water is 85 degrees and you don't run the heater at night how much temperature you lose. If you lose 5 degrees it can take you 4 to 5 hours of run time in the morning to get back to 85 degrees. If you are looking to swim in 85 degree water in the morning that may not work for you. If your swim is in the afternoon then the heater has time to get the water up to the desired temperature.

You need to figure out what works for you in your environment.

thank you so much, very helpful! Once we have it to 85 degrees we will see how much it drops overnight when not running. we normally swim later in the day so hopefully like you said, would have time to warm up by then. Thanks for the reply!

 

[wogster]

A solar blanket may also help, you keep the pool covered when not in use, this reduces evaporation, and cold air exposure.

 

[duraleigh]

Don't overlook the efficiency increase of a thermal cover.......it's almost mandatory to keep you heating costs reasonable.

Heat pump is almost perfect for your climate and really needs to run 24/7......it won't raise your temp fast enough otherwise.

Is that a VS pump? It really should be if you put in a heater.......allows you to run 24/7 at VERY low electric consumption.

As you have likely already discovered, that cage blocks a LOT of warming from the sun and you will probably end up running your system 8-10 months out of the year.

 

[revitup]

Our heat pump brings up our 8K gal pool temp about 1 - 1.5 degrees per hour, just what was estimated above. We like a 85 degree swim temp, we're in SC so a little cooler than your locale. We run the heat pump/filter 8 hours/day, 9AM - 5PM. With a solar cover we lose about 3 - 5 degrees overnight. Our pool is usually up to an acceptable swim temp by about noon or so, depending on the ambient. The warmer it is outside the cooler we'll accept the pool temp.

 

[Icemodeled]

Thanks everyone. we will begin to look into a solar cover as we absolutely want to save money wherever we can and keep it most efficient. Our pool is now at 85 degrees so tonight will be the test and see how much it drops.

We do not have a VS pump. If it would be greatly beneficial to switch to this we could. Will look into it as well.

 

[mknauss]

With no SWG and your pool enclosed, you should only have to run your pump a couple hours a day when you add chlorine. So a VS pump may not be economical. Unless you are running the pump alot to heat the pool.

 

[PoolBrews]

I've seen several comments stating that a VSP pump can be run at a low RPM when used with a heat pump, but I find that unless I'm running around 70% of full speed (2,400 rpm), the heat pump will not run - you get low flow indicator. I'm using a Hayward MaxFlo VS 500, Hayward C200S filter, and the Hayward HP21404T heat pump.

Anything under 2.400 rpm will cause the heater to shut down. Is this normal? Or is my flow indicator set too high? Not sure if this is adjustable or not. I'm not sure how much I save at 70% of full.