Most efficient pool heating technique

[jmp470]

Greetings all,
I seldom post on here, more of a lurker. However, I have a pool heating question. We have a 16,000 gallon in ground pool / spa with a Pentair Ultratemp 120 H/C heat pump and I was wondering what the best method for heating the pool up and maintaining temperature is. I'm near San Antonio and the temperatures we are having are lows in the 50's/60's at night and high 70's low 80's during the day and I want to heat up the pool to 84 degrees so the kids and I can start swimming.

I turned the pump on at 4pm on Thursday and set it to 82 degrees. Well today, Saturday, we swam and after about an hour the kids were getting cold. So I'm thinking I want it set to 84.

So my question is: What is the best method to sustain 84? Do I keep it at 80 during the night, then put it to 84 only when we want to swim? or just keep it at 84 the whole time?

From my research and looking online, I cannot find the exact kwh that the heat pump uses, so I'm curious what's it going to do to my electricity bill. However, I also have a large solar array on my house, which offsets about 97% of my usage now.

Anyways, any input would be greatly appreciated.

 

[ajw22]

A heat pump heats water slowly. It will not be able to rapidly raise the temperature from 80 to 84 when you want it. Best to leave it set at 84. Use a solar pool cover when not swimming to retain the heat.

Heat pump performance declines as the temperature drops and it stops heating when temperature is in the low 50s. So much of the night the heat pump may not run on cold nights. Then as the temperature rises in the morning the HP will begin running.

 

[zac280]

Heat pump performance declines as the temperature drops and it stops heating when temperature is in the low 50s. So much of the night the heat pump may not run on cold nights. Then as the temperature rises in the morning the HP will begin running.

When you say it may not run, does your actually cut off below a certain air temperature? I have a new Jandy JE3000TR, and I've noticed it'll still run in 50s air temp, but the water stops heating or drops. I can't find anything in the documentation about air temps to run this thing at, but it does spec optimal BTUs at 80F, and low ambient output BTUs at 50F, dry-bulb, and 44F, wet-bulb.

 

[ajw22]

Pentair Ultratemp HP cuts off at 50F. Don't know about your Jandy.

Heat Pump Performance

• ajw22
• Feb 23, 2019

Pentair Ultratemp Heat Pump BTU Output by OAT

 

[jmp470]

Thank you all.

 

[Pool_Medic]

As your ambient temperature drops, your wallet gets lighter. A neat trick if you have a VS pump is to run the low speeds at night, the heat pump won’t come on because of low flow, ramping it back up in day light can save you some money. Heat pumps are very expensive to run below 65 degrees.