Optimum temp for a heated pool


May 6, 2015
San Jose, CA

I have just recently gone from owning and operating a 10k gallon above ground pool to moving in a home with a 42k gallon in ground pool and spa. This is the first time I have ever had the ability to enjoy a heated pool!

I am curious about the optimum temp for a pool that size. I live in Northern California and the temp is averaging 48-52 in the daytime, and drops to about 35 during the night time hours. We had the grand kids for the new year and heated the pool for the first time. Kids will get into 68 degree water without batting an eyelash, so as temp slowly increased so did the use age. We allowed the pool to reach 88 degrees mostly to find out if it was possible. I will admit that is was a luxury to be swimming in water that warm while it was so cold, but this was a special treat.

My husband has decided that the optimum temp is between 72 and 75 degrees, while I tend to think that is should be between 78 to 82 degrees. What temp do you keep your heated pool at?


TFP Expert
Feb 3, 2014
Central Minnesota
I'd have to get another job or take on another spouse ;) to afford to heat my pool that much for any length of time. In the summer, I like the pool in the high 70s, low 80s. If it were air temps where you're at now, even low 70s would feel pretty good.


Well-known member
Aug 19, 2014
Shallotte, NC
My husband has decided that the optimum temp is between 72 and 75 degrees, while I tend to think that is should be between 78 to 82 degrees. What temp do you keep your heated pool at?
Yet another, "How long is a piece of string?, question....:jocolor:

Seriously, you are both right, but it is a matter of personal taste. We don't have a heater, but my wife and I have very similar opinions.... and feel "opening day" is a few weeks apart..... However, if you do a google search, you will find that most people are in your ballpark, rather than his. If seniors are involved, most printed material will push the temperatures as high as 88. I'm a senior and I'm good at 70 degrees... my wife, also a senior, loves the 91 degree temperatures we can get in mid summer.... I'm done, because it feels like bath water.... headed to the surf.

You are probably going to have to agree to disagree, to some extent, especially after the first "heating" bill arrives.....:)


LifeTime Supporter
Aug 19, 2014
Pacific NW
for me 78 is minimum.

83 ideal. On a warm day I can step in the pool with no shiver moment at that temp.

I've had it up to 88 but it felt like bath water.


LifeTime Supporter
TFP Guide
Jun 12, 2011
Unless you have an unlimited bank account or win the Powerball jackpot, maintaining 42,000 gallons of water at any temprature 70+ degrees when the outside temps are in the 30's is totally impractical.

You will soon learn that, (when your gas bill arrives).


Well-known member
Apr 3, 2015
New York
Hi. I leave my pool at 84 degrees and if it's cloudy I put it to 86 (based on feedback, i.e., being told to raise it). I don't have a cover but use a liquid solar blanket (not as good but seemed to help hold heat in ok). I live outside NYC and close the pool by October (open in May). Once I'm into end of June through August the heater doesn't work much at all (assuming a hot dry summer like we just had). That's a cool treat for the kids! I assume if you expect it to drop below 32 you just leave the pump running during the night right? My water on the top of the cover won't start to freeze at night until the air temp drops below 30.


TFP Expert
LifeTime Supporter
May 10, 2010
SW Louisiana
It really is a personal choice, and it does tend to go up with age, back when I was in my 20's I would have said 77 degrees as ideal and would swim in much colder, 6 years ago when I joined this message board I would have said 82 - 83 leaning towards 82, and now I am at 83 close to leaning towards 83-84.


TFP Expert
LifeTime Supporter
Jan 4, 2016
Sydney, NSW, Australia
My wife likes 86 and I like 82. At 86 it doesn't cool me off on a hot day, but I could float around in it forever. If it's sunny out, I'll jump in without hesitation at anything over 75.


Well-known member
Sep 29, 2014
Hamilton, Canada
We have much colder winters (below freezing), but our winter started very late.
So in the late fall and wintertime, I've run mine as hot as 100F, running the pool as a 20,000 gallon hot tub.

Last season (2014) we ran into early December but this year we ran our swimming pool (Hamilton, Ontario, Canada) until January 11th.

Our process was to usually let the pool cool down to 70 during the week, turn on the heater on Friday and run the heater for approximately 24 hours, to bring it up to hottub temperatures. Rinse and repeat every weekend, gives 8 nights of hottub temperatures. We've thrown many neighborhood barbecues.

Last month's natural heating bill was only $211, because of techniques I've come up with. I'll post in a new thread explaining how I managed to keep my bill low, while running my swimming pool into the beginning of winter (although winter came rather late this year!)... I used a tactic of turning off the poolpump everytime I turned off the heater (prevents pipe cooling effect), and using a solar thermal blanket whenever the pool was not in use. Often, the pool fell only 5 degrees by the time I turned the heater back on the next day. I avoid thermostat cycling (inefficient, due to ground pipe cooling effect, when heater cycles off, the water sometimes gets colder than the water in the pool, given uninsulated plumbing through the ground), and instead run the pool full-throttle heating instaed. Totalled, all these techniques allowed me to save maybe ~70%, and allows me to run the pool as one giant hottub during the late fall and early winter.

EDIT, I've posted the thread:
FAQ: Cheaply Keeping a Pool Hot -- 90F/95F/100F -- How we ran till Jan 11th in Canada

When the ambient air above the pool is near or below freezing, it is nice and toasty at 95F feeling like a hot tub.

In the summer, we run at 70-85F.