Heat pump for spa in colder temps???

[Lpge40]

Hi there,

While building our pool the pool builder offered us a deal on an in ground spa including separate pump, air blower, light, plumbing etc.
However the filter will be shared. The pool is 21000 gallons and the spa is 500 gallons. The heat pump we purchased is the Pentair Ultratemp 125000 BTU model 120, 460933. We have the Pentair variable speed pump.
We are struggling to determine whether or not this pump will be efficient enough to run the spa when temps fall into the 40's. We live in Central Texas and I just called the Pentair customer service number and they told me that once we get to the desired temperature in the spa, the heat pump will have no problem maintaining it. Is this true? And wouldn't it be using extra electricity running 24 hours a day to maintain the temp?

My apologies to those who responded to a similar post in the 'construction' forum. I just thought this forum is more appropriate.

 

[jblizzle]

I stand by my statements in your other post:

1. A heat pump typically can not overcome the heat loss when the air temp gets below 60 degrees (or 50 or 40 ... depends on whether it is covered, etc).
2. A heat pump is not typically used to raise the water temp up to 100 degrees ... it is more useful to maintain water temp in the 80-90 range when the air temp is similar.

You will not be happy trying to use a heat pump to heat a spa in the winter.

There are a lot of threads discussing heat pumps that you can search for ... although usually just for use on pools. Here is one:
electric-heat-pump-t53180.html?hilit=heat%20pump

If you managed to get the spa up to 90-100 degrees in the winter AND you had a good cover on the spa AND you ran the pump and heat pump 24/7 on the spa only (which means your pool will not be circulated and cleaned), maybe it could hold the temperature in the spa like they state, but it is going to cost a LOT of money in electricity. Much cheaper to just run a gas heater for the few hours when you actually want to use the spa.

 

[keastman]

I'm in NE Florida with a similar sized pool and spa. My system had a heat pump smaller than yours when I first moved in. Though it was on it's last legs (only 5 yrs old). I did use it to heat the spa in the winter and in temps in the high 40's-low 50's. I did not keep the spa heated. I'd only turn on the spa and heat pump on when I wanted to use the spa. Unfortunately, you'd have to let it heat up for an hour and a half or so to get it up to temp. I never took the I'd run the temp at about 100 to 102 starting from water temps in the 50's without a problem. The heat pump crapped out within two years and I've since yanked it out of the system because we never used it for the pool. Were I to add a heater again, I'd likely go with gas since it will heat the spa a lot faster when you want to use it and they are less expensive to purchase. I'm not sure if the operating cost are lower though vs a heat pump since propane is rather pricey. If I planned on heating the pool to extend the season, then I'd replace the heat pump and suffer the longer warm up time for the spa. I'd also put a cover on the spa and just bring it up to temp when I wanted to use it. On a weekend, I might throw some extra chlorine in and keep it out of the pool loop to retain heat for daily use. I don't see a practical way around heating the spa up for each individual use if it's attached to the pool system.

 

[jblizzle]

From my understand, which is limited,

That could not have been a heat pump. Must have been a resistive electric heater.

Heat pumps would take days to raise the temperature when the air is that cold and would never get near 100.

Posted from my Droid with Tapatalk ... sorry if my response is short

 

[Vinoveritas]

I live in Austin, have a 400k btu heater and it still takes 30 minutes to get to 99 degrees on spa mode. I can't imagine how long you will need to heat the spa to get to spa temp. Well I guess it would be over an hour and a half actually. Will the spa overflow into the pool?