Question for those with pool heat pumps

[No Clue]

I just had a new Hayward 140k btu heat pump installed last week. I wanted to get it going to make sure it was working and see how well it worked. My pool is about 35k gallons.
Our outside temperatures haven't been great with overnight temps in the 40's and daytime temps around high 60's and low 70's. It has been running since Wednesday evening and the current water temp is about 77. It started around 64 degrees.
My installer doesn't have a great sense of whether it should heat faster or not but urged me to give it a few days. He said once the daytime temps get into the 70's, it should heat pretty quickly. Some of the videos on youtube said it should heat 1 to 1.5 degrees per hour but they didn't mention what outside temps need to be.
I know I am wasting $$ trying to heat it now but I wanted to verify it was working before it really counts in a couple of weeks. What should I expect with regard to how fast it heats up?

 

[Newdude]

Is the pool covered ? If not you'll likely lose more at night than you produced during the day. Even then the HP may not be able to overcome the weather. 35k gallons needs alot of BTUs to heat and the HP only has 1/3 the BTUs of a gas heater so it's starting at a big disadvantage.

On the plus side, your HP probably works great, just not yet.

 

[No Clue]

Is the pool covered ? If not you'll likely lose more at night than you produced during the day. Even then the HP may not be able to overcome the weather. 35k gallons needs alot of BTUs to heat and the HP only has 1/3 the BTUs of a gas heater so it's starting at a big disadvantage.

On the plus side, your HP probably works great, just not yet.

It isn't. It seems to be holding its own during the night and only gaining during the day.

 

[Newdude]

seems to be holding its own during the night and only gaining during the day.

A solar cover is a must for retaining overnight water temps in the early/late season. Then you'll be starting the next day off in a better place.

70% of heatloss is through evaporation, and a cover nearly stops all evaporation.

 

[No Clue]

A solar cover is a must for retaining overnight water temps in the early/late season. Then you'll be starting the next day off in a better place.

70% of heatloss is through evaporation, and a cover nearly stops all evaporation.

I don't have a solar cover and looked into them but I don't think I want to deal with the storage issue and mess. I have a lot of trees around the pool that really drop a lot of stuff this time of year. I have added the liquid solar blanket to see if that helps.

 

[Newdude]

I have added the liquid solar blanket to see if that helps.

With the slightest breeze liquid covers are pushed to the downwind side of the pool. It's an amazing theory that didn't pan out in the real world as there is almost always some level of breeze.

If you don't want a real solar cover, then it is what it is and the weather will decide how well it works. I'd shut it off at times like now as you are paying the most electricity it will use all season, yet getting little from it.

 

[JamesW]

This is a different model, but the performance should be similar.

Below 50 degrees Fahrenheit will result in poor performance and a lot of heat loss.

36,000 gallons is about 300,000 lbs of water.

Assuming a 50°F (10°C) Air Temp, 63% RH, 80°F (27°C) Water Inlet Temp, the heat pump should produce about 88,000 btu/hr, which is 0.293 degrees of heat added per hour.

The loss rate can easily be this high or higher resulting in no net heat gained and even heat loss.

https://www.pentair.com/content/dam/extranet/nam/pentair-pool/residential/heaters/ultratemp/ultratemp/ultratemp-heat-pump-installation-and-users-guide-en-fr-sp.pdf

https://www.pentair.com/content/dam/extranet/nam/pentair-pool/residential/heaters/ultratemp/ultratemp-heat-pump-literature/ultratemp-high-performance-heat-pump-brochure-english.pdf

 

[No Clue]

This is a different model, but the performance should be similar.

Below 50 degrees Fahrenheit will result in poor performance and a lot of heat loss.

36,000 gallons is about 300,000 lbs of water.

Assuming a 50°F (10°C) Air Temp, 63% RH, 80°F (27°C) Water Inlet Temp, the heat pump should produce about 88,000 btu/hr, which is 0.293 degrees of heat added per hour.

The loss rate can easily be this high or higher resulting in no net heat gained and even heat loss.
View attachment 479760
View attachment 479761

https://www.pentair.com/content/dam/extranet/nam/pentair-pool/residential/heaters/ultratemp/ultratemp/ultratemp-heat-pump-installation-and-users-guide-en-fr-sp.pdf

https://www.pentair.com/content/dam/extranet/nam/pentair-pool/residential/heaters/ultratemp/ultratemp-heat-pump-literature/ultratemp-high-performance-heat-pump-brochure-english.pdf

Thank you, it looks like mine is doing what it is supposed to do.

 

[Mdragger88]

Heating a pool without a cover to prevent evaporative heat loss in cold temps is kinda like burning $$ - the next utility bill is probably going to be a doozy.
A solar cover doesn’t have to be all one big unruly piece, you can use multiple ones. Lots of people buy 2 small ones or cut a large one in half. That can also make them much easier to deal with & store if you’re not into having a reel on the deck.
The liquid stuff may help with evaporation minimally as @Newdude pointed out, but I don’t like the film it leaves behind.

 

[No Clue]

Heating a pool without a cover to prevent evaporative heat loss in cold temps is kinda like burning $$ - the next utility bill is probably going to be a doozy.
A solar cover doesn’t have to be all one big unruly piece, you can use multiple ones. Lots of people buy 2 small ones or cut a large one in half. That can also make them much easier to deal with & store if you’re not into having a reel on the deck.
The liquid stuff may help with evaporation minimally as @Newdude pointed out, but I don’t like the film it leaves behind.

Now that I know it is working like it is supposed to, I turned it off and will wait for warmer weather. My main goal was to be able to add May and most of September to my swim season. I don't like getting in unless it is 85 or higher and I should be able to get that in May without being too expensive.