Does pool heat better with/without cover?

miahhough

Well-known member
Aug 4, 2011
46
#1
This is probably a silly question but which is better to let the sun heat the pool. I can make arguments for both. (I have a dark blue auto cover). if the cover is on it keeps the heat in. if the cover is off it alows the sun to hit the water directly. which way do you think will cause the water to heat better?
 

JasonLion

TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
37,879
Silver Spring, MD
#4
For best heating, the cover should be on when the sun is not shining directly on the water. When the sun is shining directly on the water you are usually better off with the cover off, though that isn't quite always true (lots of wind tends to make a cover worth it even when sunny).
 

mickey4paws

Bronze Supporter
LifeTime Supporter
Apr 10, 2009
593
S.E. MI
#5
Mostly I keep my cover on during the day if it's going to be windy in order to keep all the leaves and junk out. I also think it heats it better. I cover it at night because it seems to hold the heat in better than uncovered.

I do wonder if keeping it covered most of the time isn't good, like does the pool need to breath?
 

harleysilo

TFP Expert
LifeTime Supporter
Mar 1, 2012
1,924
North Georgia
#6
harleysilo said:
Cover on! Pool pump running while your getting sun.

automatic-cover-observations-coverstar-t46899.html

I should state that this is my first pool and first pool season so my experience is limited.

We bought the auto cover to keep our kids and pets safe. The side benefits being limiting chemical use, reducing evaporation, virtually eliminating debris in the pool and heat retention (all though I was told a bubble wrap blanket works better for this).

That said I only uncover the pool to swim or run the polaris. So my pool has been on average covered for 20-22 hours a day (except on weekends where we may swim longer but still cover when not swimming/running polaris).

What I have noticed is that with the pump off and pool covered on sunny day, when I open the cover and start swimming the top 12" of water is super hot, and the bottom couple feet is noticeably cooler. With the pump running while cover is on and it is sunny, when i uncover and get in i don't notice this layer of superheated water. I my a comment to the Coverstar rep about how hot our pool was and he asked me when my pump ran. At that time it was running 24/7, I told him and he said that's why it's getting so hot. Then he explained to me what I've now discovered on my own. If i want to heat up the pool run the pump with cover on and sunny causing the water at the top that's getting so hot to circulate bringing new water to top to heat etc. If i would like to minimize the heating on sunny day with cover on turn off the pump so that the water doesn't change out below covers surface.

Unfortunately at this time i have no experience without the cover on, but if my pool keeps getting hot I might have to start leaving it uncovered during the sunny afternoons (because i think it would be more apt to not heat up as much without cover), but that may indeed be completely wrong as Jason mentioned above baring wind conditions.
 

harleysilo

TFP Expert
LifeTime Supporter
Mar 1, 2012
1,924
North Georgia
#7
mickey4paws said:
Mostly I keep my cover on during the day if it's going to be windy in order to keep all the leaves and junk out. I also think it heats it better. I cover it at night because it seems to hold the heat in better than uncovered.

I do wonder if keeping it covered most of the time isn't good, like does the pool need to breath?
I was told that the only time I needed to leave it uncovered was when chemicals are out of wack, meaning when I'm shocking the pool. This is to prevent damage from high chlorine levels that could impact the cover.

Bottled water comes with a lid, no? :?: