New Spa build with Pentair Ultratemp 120


Jul 28, 2020
San Antonio, tx
Hello everyone,

We are in the process of having a pool and spa built and have been offered a Pentair Ultratemp 120 for heating the spa (7'x7'). We live in San Antonio, TX- so winters aren't harsh and our lowest temps average 40F and only for a few days at a time. I have read a lot about using gas heaters for the spa, but have had little success finding info about how well this equipment works for the spa. Does anyone have this same model or similar for their spa? If so, have you had any issues with getting the spa up to a comfortable temperature during winter?



Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
Bedford, TX

I am not a heater expert, but heat pumps are best for slowly bringing something up to temperature and keeping it there. Normally, this is not how most people use a pool/spa combination.

Let's see what our other members have to say..


Jim R.


TFP Expert
Bronze Supporter
In The Industry
Aug 10, 2017
Morris Cnty NJ
It would work fine depending on water temp. You may need a few hrs to reach 100 if water is 40 degrees. A cover helps hold heat in if you can isolate the tub that way
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