Heat pump efficiency

rpeck

Gold Supporter
Jun 5, 2020
15
Austin, TX
This is our first spring having our pool. I am trying to figure out the best balance between letting the kids swim and killing our electricity. We have an electric heat pump, no gas. From what I have read, heat pumps cannot heat the water when the air temp is below about 50 Fahrenheit. My question - is it worthwhile running the heater overnight when the temp drops into the 40s? Even if it cannot heat the pool further, does it conserve energy vs turning the heat on mid morning when it warms up a bit?
 

jeremycrook

Gold Supporter
Sep 26, 2016
211
OKLAHOMA CITY / OK
Pool Size
11000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Jandy Truclear / Ei
You are in a little warmer climate then I am, depending on when Old Man Winter wants to leave, we generally don't start heating until the temps in the evening are around 50*. We have swam around Easter, but only a few times. You can leave the HP on, but adjust your pool's timer to come on and off when the temps fluctuate. The HP stays on if your pool turns off, just a suggestion.
 
Last edited:

Newdude

Mod Squad
Gold Supporter
TFP Guide
Jun 16, 2019
16,605
NY
is it worthwhile running the heater overnight when the temp drops into the 40s?
No. Think of your AC, but in reverse. When it's warm out, the HP will breeze along sipping energy like the AC does on a cool day. When it's cool out, the HP will bog down and smoke your electric meter spinny thing just like the AC would when it's 110 degrees.

At 70 degrees the HP efficiency falls off a cliff. At 60, it may or may not work at all. It may hang on a bit longer with the water already warm, but either way you are pushing its capabilites.

You want a solar cover to greatly reduce evaporation which is where most of your overnight heat loss comes from. When it warms up during the day, you will only have to make up a few degrees and it will be wallet friendly for the HP to do so in favorable conditions.

You only need the cover at season extending times. Once it's TX hot out, you'll welcome it cooling off down to only boiling.
 

JustPeachy

New member
Mar 16, 2022
2
Virginia
This is our first spring having our pool. I am trying to figure out the best balance between letting the kids swim and killing our electricity. We have an electric heat pump, no gas. From what I have read, heat pumps cannot heat the water when the air temp is below about 50 Fahrenheit. My question - is it worthwhile running the heater overnight when the temp drops into the 40s? Even if it cannot heat the pool further, does it conserve energy vs turning the heat on mid morning when it warms up a bit?
Looks like that model has defrost, so its designed to work in colder temps. But - it doesnt work off inverter technology, so youre basically looking at burning 6kw while its running. Since its not variable speed you save money when its off as opposed to just letting it continuously run.

You'd need to see how long it runs to heat your pool up when you turn it on during warmer temps to recover lost temps, vs how much it runs all day/night when temps dip. Less run time is what you're after (opposite an inverter system).
 
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