Pools, Spas and Hot Tubs - solar pool cover dilemma...on or off to warm??????????
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dingoohio
08-08-09, 09:16 AM
Can I have opinions on whether it is best to leave on or take off your solar cover to warm your pool on a sunny day? I was of the belief that you leave it on(hence the name"solar" cover) to let the sun heat it up so water will get warmer. I do cover it at night for evaporation/heat loss/chemical use benifits. I have come across a friend that says he was told to take it off and the sun will warm/penetrate water better. I decided to call different pool stores and of course got 2 different directions. Outside of performing my own experiment(lol) I figured this was the place to get answers. I know we will probably get both sides. Just want your thoughts. THANKS
Gunguy45
08-08-09, 09:21 AM
If I remember from quite a while back...leave it on whenever yer not using the pool. It also helps prevent evaporation which will lower the water temp.
JMO no pool expert
JMO no pool expert
the_tow_guy
08-08-09, 11:10 AM
I'm inclined to think you will get more warming with it off on a sunny day. :coffee:
Gunguy45
08-08-09, 11:22 AM
Ok..looked at some stuff....mostly here..Solar Pool Covers (http://www.solarhome.org/solarpoolcovers.html) ..pretty good info.
"Evaporation requires a tremendous amount of energy. While it only takes 1 Btu (British thermal unit) to raise 1 pound of water 1 degree, each pound of 80ºF water that evaporates sucks 1,048 Btu of heat out of the pool.
The evaporation rate is dependent on the pool’s initial temperature, the surrounding air temperature and humidity, and the wind speed at the pool surface. The higher the pool temperature and wind speed and the lower the humidity, the greater the evaporation rate. Though a windbreak— such as trees, shrubs, or a fence—can reduce evaporation, it may shade the pool from the sun, which is a strong natural heat source for the pool"
A pound of water isn't very much..a gallon is about 7.5 lbs if I remember correctly.
So if its a dry windy hot day (say like right here in N AZ)...a cover is a good idea. But if its a sunny, calm, humid day (like in OH where I grew up)...maybe not.
Basically...it depends...lol
"Evaporation requires a tremendous amount of energy. While it only takes 1 Btu (British thermal unit) to raise 1 pound of water 1 degree, each pound of 80ºF water that evaporates sucks 1,048 Btu of heat out of the pool.
The evaporation rate is dependent on the pool’s initial temperature, the surrounding air temperature and humidity, and the wind speed at the pool surface. The higher the pool temperature and wind speed and the lower the humidity, the greater the evaporation rate. Though a windbreak— such as trees, shrubs, or a fence—can reduce evaporation, it may shade the pool from the sun, which is a strong natural heat source for the pool"
A pound of water isn't very much..a gallon is about 7.5 lbs if I remember correctly.
So if its a dry windy hot day (say like right here in N AZ)...a cover is a good idea. But if its a sunny, calm, humid day (like in OH where I grew up)...maybe not.
Basically...it depends...lol
the_tow_guy
08-08-09, 11:59 AM
About 6 lbs to the gal I think, but you have a dry heat out there, so maybe the water weighs more. :rolleyes:
Gunguy45
08-08-09, 12:16 PM
OK TG...not gonna argue...but dude you are soooooo wrong! lol
Went and checked..I was thinking of diesel or oil or something with the 7.5lbs. Fresh water actually weighs about 8.3 lbs per gallon. "pints a pound the world around" ring a bell?
Went and checked..I was thinking of diesel or oil or something with the 7.5lbs. Fresh water actually weighs about 8.3 lbs per gallon. "pints a pound the world around" ring a bell?
todrut
08-08-09, 04:16 PM
Solar cover on when not using pool. Solar cover on on a sunny day for best heating from the sun. Leaving cover off on a sunny day will NOT heat as well. Cover on at night retains heat.
tribe_fan
08-09-09, 09:30 AM
I agree with Todrut -
If you want proof - leave the cover on a sunny day, then measure or feel the temperature near the top vrs the bottom of the water.
If you want proof - leave the cover on a sunny day, then measure or feel the temperature near the top vrs the bottom of the water.
dingoohio
08-09-09, 07:49 PM
sunday here in ohio it was 90 degrees and mostly sunny. pool temp at 10:00 am was 79 cover was on till 6pm and the temp rose to 83 degrees. weather tommorow should be about the same. i will take cover off all day and see how much it warms. I feel like that science guy! lol see how exciting it is in ohio?! hehe
Crocostimpy
08-13-09, 03:10 PM
Ok here's my opinion. This is the second summer since we bought our house with the pool (15x30' above ground)already there. Last summer we unrolled the solar cover every time we weren't using the pool. When it sat in the sun for a while the water would warm up quite well, but only the top 6 or 8 inches. And then as soon as the kids would get in and start playing it would all get mixed together and wouldn't make a difference anymore.
The other thing I didn't like about the cover was that at night when I ran the filter any debris that was on the cover would not get sucked into the strainer. Then when I rolled up the cover it would all end up in the pool and would have to be cleaned out.
I can see how it may help with evaporation, but to me it's not worth the trouble. This year I haven't even gotten the cover down from the garage at all. Of course, this year has been pretty sucky for poolsin the Chicago area. It's been below average temps almost the whole summer. And the only time it was really hot (a week at the end of June) we were on vacation in Wyoming where we were wearing jeans and sweatshirts the whole time!
The other thing I didn't like about the cover was that at night when I ran the filter any debris that was on the cover would not get sucked into the strainer. Then when I rolled up the cover it would all end up in the pool and would have to be cleaned out.
I can see how it may help with evaporation, but to me it's not worth the trouble. This year I haven't even gotten the cover down from the garage at all. Of course, this year has been pretty sucky for poolsin the Chicago area. It's been below average temps almost the whole summer. And the only time it was really hot (a week at the end of June) we were on vacation in Wyoming where we were wearing jeans and sweatshirts the whole time!
Gunguy45
08-13-09, 03:25 PM
Probably depends a lot on color of the interior of pool..inground or above...etc.
Ours was 18 x 36 inground.
My parents finally bought a roll up cover back in OH. The roller mounted just under the diving board end..no clearance issues. Took 2 people to deploy it easily..but 1 could roll it up by cranking the handle. Cover for the rolled up solar for the winter.
They finally also bought a winter cover to keep leaves and turtles and frogs out. Not sure how that one worked, it was after I left home.
Heres a funny..1st year there, when we were pumping out and getting the pool ready...my older brother went crazy trying to get out of the diving end. Turned out there was about a 12" snapping turtle hibernating (apparently) in the deep end.
We took him to a local creek (or crick..as we said) and wished him well.
Ours was 18 x 36 inground.
My parents finally bought a roll up cover back in OH. The roller mounted just under the diving board end..no clearance issues. Took 2 people to deploy it easily..but 1 could roll it up by cranking the handle. Cover for the rolled up solar for the winter.
They finally also bought a winter cover to keep leaves and turtles and frogs out. Not sure how that one worked, it was after I left home.
Heres a funny..1st year there, when we were pumping out and getting the pool ready...my older brother went crazy trying to get out of the diving end. Turned out there was about a 12" snapping turtle hibernating (apparently) in the deep end.
We took him to a local creek (or crick..as we said) and wished him well.