solar heating-check my thinking please.

[tenax]

I used the calculations program..it was very revealing!

heater with no solar cover, no solar heating panels-heating cost (based on an 83 degree optimum pool swimming temp and variables for my area of calgary) 2243 dollars for the 5 month swim season for ngas.

heater with solar cover on anytime not swimming, no solar panels- the heating cost for the season drops dramatically to 1036 per season.

heater with solar cover and a 8 ft x 20 ft solar panel array- the cost drops to 729 per season.

clearly, the value of a 100 dollar solar cover is huge..the solar array will pay for itself at a 1,000 to install myself in 3 seasons.

it was an easy convincer for my wife of my next project this spring

[tphaggerty]

I think the % coverage info is actually target more at year round users (like in FL and CA) where the idea is to be able to swim year round even when average temps are in the low to mid-70s. Also, the worse the orientation, the more coverage you need.

In the NE, coverage can be less because we only turn the thing on during late spring/summer/early fall when the temps are higher. HOWEVER, as I have stated elsewhere, the nicest thing about more coverage is better recovery time. My 20x40 IG could easily get to the low 90s - when the stupid sun shines! Right now, due to all the rain and sparse sun, we are in the high 70s! (Still better than our neighbors, but not good enough). I would love to have twice the coverage just so that I could get back into the 80s in a day or two instead of 3 or 4. That is probably next years project (I just have to decide if I am going to add 5 panels to the back side of the garage, or GO FOR IT and add another 8 panels to the front roof).

[CarlD]

OK: I ALWAYS use the solar cover with a good reel. It's just too hard to keep the water warm at either end of the season. During the Dog Days, I don't use the cover and try to run the panels only at night to cool the water.

I assumed the cover was part of the deal. I don't find them to be much of a problem. I can crank it off in a couple of minutes and with help from my older kid, we can cover it even faster--maybe a minute. I can live with that much inconvenience!

[tenax]

no question the cover was the smartest thing that i did this spring (and the first..even though i didn't have a clue at the start of the season why that is what i did first aside from i knew it was going to be the cheapest item in a long string of goods to get my pool up to snuff) glad i didn't get the heater in spring now...and the cover at end of the process

winter will include spending time spec'ing out parts and cost for solar goods. 350 bucks is not an extraordinary saving per year, but hey, it's 70 bucks a month, it's 70 bucks a month.

the key for me is keeping the financial investment practical. if i can keep it at about 1,000 i can see us being here that far in the future..if it was say 2000 dollars, that's 6 years to pay off. my eldest will likely be gone from the house 2 years before it pays for itself, the youngest will be 18 and likely on his way out by then.

then, we start asking ourselves the question if we want a house with a pool anymore or not..i know , i know..some may shudder at the thought..but it really does become impractical if:

-my wife will rarely swim (which is the case)
- i use it even once a day for an hour.

a hottub at that point would likely be more practical for my wife and i

[pj1016]

mas985 in post #6, and tphaggerty in post #8 are spot-on.

Bottom line: The amount of panel area needed is directly related to:

1) How long you want your swim season to last.

2) How much daily sun exposure you have where you intend to install the panels AND what you have on your pool through the day.

3) Are you willing to use a pool cover.

4) Is your pool subject to any cooling effects from wind.

5) How fast you want the water temp to rise.

I think that we can all see that everyone's wants and needs and thus hardware requirements will vary substantially.

pj

[msm859]

Has anyone tried using smaller panels that are enclosed with glazing? It seems they would warm the water more and thus be as effective as a larger "less" efficient area.

[tphaggerty]

Has anyone tried using smaller panels that are enclosed with glazing? It seems they would warm the water more and thus be as effective as a larger "less" efficient area.

There is quite a bit about this on the web and even here on the forum. Those panels are designed for heating a small amount of water to a much higher temp than pool panels, but at a much lower volume. To get the same amount of heat into the pool, you would be spending much more money.

Remember that heat is temp rise * flow rate. At 4 to 10 GPM (which is typical for pool panels) per panel, with 8 panels, I get between 32 and 80 GPM of water at a 2 degree rise. A typical glazed panel will heat 30 to 60 gals of water to about 175 degrees over an hour plus. To get the same heat, you would need a significant number of glazed panels and they are expensive. They are just designed to do a different job. Sort of like comparing a Honda Fit to a semi. Each is more "efficient" at doing what they are supposed to.