Solar heater experiences?

[justinharlow]

I am intrigued by the size of solar panels that people in this forum seem to be getting by with. We live in Florida, and have a 24 foot above ground pool. All of the local solar panel contractors seem to think we need four (count 'em) of those 4' by 12' panels to keep the pool at a decent temperature from March through November. The temperatures in March here are typically high 40s to low 50s at night and 60s in the daytime. November is warmer than that. Our pool is in direct sunlight about 12 hours a day, and we have a solar blanket for night use. I don't like to get in the pool when the water is less than 82 degrees, and I really prefer 86-88.

They all come armed with intimidating tables and calculations, but it sounds like you folks are getting by with half (or less) than what these "experts" recommend. I'd be interested to hear about other peoples' experiences with solar before I go spend $3-4K on too big an installation.

Thanks

Justin Harlow

[mustBnuts]

We have a 13 x 30 inground fiberglass pool. We have 2 of the 4 x 20's bought from Ebay. I put them on a flat rack next to the pool filter. I've been heating with them this season since 04/10/06. The kids went swimming in 82º water on Easter Sunday 04/16/06. 80º is my min. temp and I really like 84º - 86º. The pool was 83º today. We use a solar blanket when not in use and at night. I'd say that the solar panels are a little less than half the surface area of the pool. I use a small 1/16 hp pump, called a tiny might, to circulate the water through the panels for 9 hrs. a day when the sun is out. This pump uses about the same amount of energy as a 100 watt bulb. I can use the small pump because I don't need to lift the water up to a roof.
I figure we've extended the swim season by 6 weeks on the front end and 4 weeks on the back end, closing by Oct. 1st. We are located in Oklahoma at about 36º latitude.
The panels get sun from 9am- 6pm. The pool gets full sun from 9am - 4 pm.
Hope this helps. This has been my experience anyway.
The pool holds the temperature at night pretty good, only losing about 2º if it stays above 60º.

[NWMNMom]

We had an 18' round AG in the past and got by with one 2x20 panel from May - the first weekend of Sept in far northern Minnesota. The water stayed about 82-88 degrees all the time except mid July when it went up into the 90s. We are installing an 18x33 AG which will use one 4x20 and the 2x20. I don't think we will have a problem keeping the water warm unless we have an unusually COLD or sunless summer.

With a 24' AG, I would think that the same config we have or 2 of the 4x20s should suffice, especially as far south as you are. You MUST have a solar blanket to keep the heat in. All told with the blanket, less than $500 expense there. Sounds like your pool guy wants a nice commission to pay for the rising gas prices!

[CarlD]

The answer is "it depends". If you want mid-80's water when the nights are 40's-50's and the days are 60's then the dealers aren't too far off. I suspect a 4x12 is a custom panel and may be expensive. Standard sizes are: 4x10, 2x20 and 4x20. 4 4x12's are about like 2 4x20's and 1 4x10 (192 sq feet vs 200 sq feet).

But if you are talking warming the water when the air is in the 70's and 80's, 2 4x20's will easily be enough, and 1 4x20 plus 1 4x10 should be enough.

The standard formulas for how many panels you need 'WAY overstate most circumstances. It doesn't hurt, but you may spend a lot of money you don't need to spend. A good installation should allow for more panels to be added easily. It's all just PVC so it's easy to plan for additional panels to be plumbed in.

But given your description of March days, with implicit wish to swim, I don't think the dealer is steering you wrong on sizing.

[abadubs]

Your 4x12 is little more than half of our typical 2x20's. A 4x20 is really 2 panels of 2x20 connected. For a 27' AG we use 3 2x20's. A 4th would warm things up quicker, but for now we'll stick with the space/cost of the 3. They only lasted 2 years and got many leaks so now we're stuck replacing them, but it's still cheaper than a gas unit. Plus in WI I imagine our nights get cooler.

[cleancloths]

Make sure you cover the pool at night to prevent heatloss. If you do you should be ok with less. Nice thing is you can start with fewer and if needed just add more - no wasted money.