1. ## Amazon Ecosaver solar. My experience/info/why I'm buying gas

Ecosaver 20 panel from Amazon. 20'x2.5' 50 square feet. \$140 + ship. I bought one of these knowing I'd need more than one, just to try it out and see what it would do. I posted about this before I bought it and heard I may need 2 or 3. I'm finding out with some measurements and math I'd actually need around 6 for my almost completely shaded pool. (It says on the box one is good for an up to 24' aboveground LOL)

I've seen recomendations that one should have 50-100% their pool square footage as solar. 6 panels would be just over 100% for me, complete shade will do that to a pool I guess.

Got this setup last thursday, yesterday a week later was the 1st day of real sun we had.

The construction of it is 22 ~3/8" tubes flowing water 20 feet one direction and 22 more tubes flowing it back the other direction tubes have plastic between them holding them in groups of 11. 880 feet of tube in all.

I am running it with a real weak (dedicated to solar) pump and small restrictive 3/4" 30 foot long hoses to get it where the sun is. I know high flow, low temp-delta is what you really want to shoot for but keep reading.

Here's how I arrived at my 6 panels-needed #:

Pool water was 76, water coming back into pool from panel in full-sun was 82 so it was adding 6 degrees.

82f water coming out of panel return hose filled a gallon jug in 15 seconds so 4gpm, 240gph, 1920 pounds per hour.

If a btu is 1 degree f added to 1 pound of water, adding 6 degrees to 1920 pounds over an hour is 11520 btu/hr

Pool is 7000 gallons, 56000 pounds.

11520 / 56000 = 0.205 11520 btu/hr will heat 56000 pounds of water by .2f every hour.

Doing some googling for "solar btu square foot" has lead me to a few sites saying that the max solar radiation you could ever pick up with some theoretical 100% efficient god-panel that's never been made is 320 btu/hr per square foot. 50 square feet = 16000 btu/hr on a "perfect panel" which is perfectly positioned + perfect flow. I got 11520, 72% of that perfect # using cheap panel, weak pump, small hoses and having it lay flat on the ground. 72% of perfect is pretty good I'd say. If it were the perfect panel, 16000 btu/hr would heat the pool by .285f every hour instead of .205 and I could do it with 5 of them instead of 6.

Now I wonder how much of my 28%-less-than-perfect comes from the cheap panel and how much comes from the low flow.

I want to be able to heat whole pool by up to 10 degrees any given day. If I had 6 panels it would heat by 1.2F every hour giving me the 10 (well 9.6) degree temp change over 8 hours I'm looking for. I don't have the room for that or the \$700 for 5 more when I see used gas heaters selling for \$300 sometimes less on CL.

I also can't see 6 of these panels at a cost of \$840 lasting long enough to pay for themselves vs. paying for gas. A proper solar heating system yes. (and we want the 16'x32' intex next year would need about 12 of these panels for that)

2 or 3 of these panels I still think may be good for people with wamer pools already in the sun needing a bit of a boost.

So, I'm going to be watching craigslist for cheap gas heaters for next year, I did the math on that and a 100kbtu one should heat up this pool 10 degrees in about 6 hours. To feed it, the .6mbtu gas for one 6 hour run is about [s:tnzjghjh]\$2.25[/s:tnzjghjh] \$4. (and we won't have to rely on the sun being out.)

2. ## Re: Amazon Ecosaver solar. My experience/info/why I'm buying

BUT ... you do not need to add 10 degrees everyday. With the use of a cover, you may only loose a couple degrees overnight, so really you should only need to add a few degrees to maintain the desired temp.

Sure initially it will take a while to get up to temp, but to me the "requirement" of adding 10 degrees per say is pretty high. From what I have read, most people with full on solar panels (myself included) only generally get 5 degrees or so a day.

Of course still depends on your goal. If you are hoping to heat the pool up in the winter or something, then clearly solar is not the right choice. If you just want to boost the temp a bit in the summer and/or slightly extend the season on either side, then solar can work well.

3. ## Re: Amazon Ecosaver solar. My experience/info/why I'm buying

Current extremely low rates on natural gas does make it a potentially viable alternative to solar for some people. However if you consider some of the better solar panels with longer expected life solar can still make sense , at least for some of us.

Ike

4. ## Re: Amazon Ecosaver solar. My experience/info/why I'm buying

Originally Posted by jblizzle
Of course still depends on your goal. If you are hoping to heat the pool up in the winter or something, then clearly solar is not the right choice. If you just want to boost the temp a bit in the summer and/or slightly extend the season on either side, then solar can work well.
I want to extend the season a lot on both ends, and be able to immediately recover from extended bouts of cold rainy days during the summer. This wasn't my original goal in 1st looking in to solar, original goal was going to be for "extending the season slightly" but now that these panels have made me think about btus/gas/cost of everything, I've got the bug to get a gas heater and be swimming in april and october.

Also I'm way too lazy to bother with a cover. I'll get up and get going for a neat project like setting up this panel or a heater but messing with a cover every day isn't something that would ever get done at our house.

5. ## Re: Amazon Ecosaver solar. My experience/info/why I'm buying

Of course you can always to both ... that is what I have (although I did not hook the gas heater back up after re-plumbing the pad yet). Although the heater came with the house, so I did not have to buy it.

The gas heater will work great any time of year ... but you are paying every time it turns on.

6. ## Re: Amazon Ecosaver solar. My experience/info/why I'm buying

Even though I'm too lazy to mess with a cover, how much heat loss do they really stop on a summer escapes/intex type pool that has the liner completely exposed to everything? Do they lose a lot of heat due to exposed liner? or not and covering up the top would help a lot?

7. ## Re: Amazon Ecosaver solar. My experience/info/why I'm buying

Most of the heat loss is from evaporation ... so the cover can help a good bit.

I am too lazy too BTW ... although may try to use one in the fall/spring to extend even more.

8. ## Re: Amazon Ecosaver solar. My experience/info/why I'm buying

Most of the heat loss is due to evaporative cooling on the surface, so a cover can make a big difference

9. ## Re: Amazon Ecosaver solar. My experience/info/why I'm buying

I'm not questioning your math, but 2.25 seems cheap for 6 hours run time on 100k btu. That would be hard to argue against. And it you cover it you won't need to run it that long, nor even daily unless you use it daily.

10. ## Re: Amazon Ecosaver solar. My experience/info/why I'm buying

I saw an example bill on the gas company website says a dekatherm (which is supposed to be 1 million btus from what I've read) costs 3.73. I need to check my actual bill when I get one and see if that's for real.

Edit : OK I was wrong on that. Found an old bill and minus the static monthly service charge a dekatherm costs 6.90 with all taxes and everything. Little less than twice what I thought but still real doable ~\$4 per 6 hour run and I won't be needing to do 6 every day all season or anything.

Edit again: wow unrelated but I got curious, a gallon of gasoline costs 3.21 here and has 125000 btu energy, an eighth dekatherm, if we paid the same rate as my natural gas company for the same amount of energy, a gallon of gasoline would be 86 cents.

Or if we paid gasoline prices for ng, energy unit-for-unit your \$100 winter heating bill would be \$373

11. ## Re: Amazon Ecosaver solar. My experience/info/why I'm buying

You will probably be a bit disappointed with the season extending effects of a heater. When air temps start to drop, the swimming becomes less attractive to many people even if the water is warm.

12. ## Re: Amazon Ecosaver solar. My experience/info/why I'm buying

Thanks for the detailed evaluation. Coincidentally I just ordered this Ecosaver solar panel from Amazon but I haven't received it yet. With the free shipping option it is scheduled to arrive early next week.

Overnight temps here have dropped into the low 50's. Even with the solar blanket on 24/7 my small pool (4,000 gal.) water temp will change +/- 5 degrees per day. Water was 75 this morning, but with full sun it was 80 by late afternoon. My kids thought it was cold but I don't care, I swim every day. However a few more degrees will make it more comfortable, and that's what I'm hoping the solar panel will give me. I'll let you know.

13. ## Re: Amazon Ecosaver solar. My experience/info/why I'm buying

Originally Posted by DigbyAllen
My kids thought it was cold but I don't care, I swim every day.
haha wife and I are the opposite here, kids will get in no matter what, it's reading 78f water temp today and a cool ~78 air temp and neither of us grown-ups will go near it.

14. ## Re: Amazon Ecosaver solar. My experience/info/why I'm buying

My heater is 100k btu and it runs about \$1.30/hr, IIRC. Without a cover your heater could easily run all night to maintain 85 if we're talking end or beginning of the season.

The worst expense was installation, our gas line had to be run about 120' which cost almost \$1k. It's still far cheaper than propane and solar isn't quick enough for my uses.

I plan out its usage and run the heater when I know it will be likely to maintain for a while or we're definitely going to be using the pool. It's also perfect for small bumps over a couple hours when the weather changes.

15. ## Re: Amazon Ecosaver solar. My experience/info/why I'm buying

Originally Posted by Speedo
The worst expense was installation, our gas line had to be run about 120' which cost almost \$1k. It's still far cheaper than propane and solar isn't quick enough for my uses.
.
I've got a gas line coming out of my house, I just need to bury some pvc to get water over there to it. Trouble for me is there's no electric there where the gas line is, I may keep the pump/filter/swg beside the pool where I have it now and use buried pvc just for heater and a single extension cord for the heater. Since mine's a temporary pool, the heater will be temporary as well and go into the shed in the winter, running it off an extension cord on a gfci outlet should be ok.

Or I could install an outlet there by the gas but it would come off the same circuit our microwave does, I would guess a gas heater doesn't draw that much power and would be ok like that but probably not the pump/swg. I'm not comfortable installing a whole new circuit back to the panel myself.

Heating the pool is going to be a strictly manually controlled thing here, going to be shut off if we don't need it, there's so many days the kids have sports/other things going on that we know we probably wont be swimming so we'll save on the gas bill.

16. ## Re: Amazon Ecosaver solar. My experience/info/why I'm buying

i love our ng heater couldnt do without it. i too just use it to warm up pool manually it is a hayward 250 kids are back too schooland not using pool as much now. this summer though has been very cool and rainy i fugure it cast me around \$7-8 bucks a day when i use it. i ran the gas line myself about 70feet not hard to do but you have to take your time and make sure everything is tight and fitting properly and do a complete pressure test. cost me around \$150 to run it. i did have to have gas company come out and put a larger meter in they did it free. i also just have the electric part of heater plugged in. very simple

17. ## Re: Amazon Ecosaver solar. My experience/info/why I'm buying

We got the Ecosaver panels for our 20' Intex and they do well. We're too new at having a pool for the panels to have had a fair chance yet, but we're still happy with what they accomplish despite us. We've made plumbing or electrical mistakes (but only on sunny days, mind you) but when things work the panels have been adding more heat than the pool loses at night.

We plan to get another panel set and install the whole bunch properly (location and plumbing both need major improvements), but yes, these panels are good at heating water.

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