From a local solar installer. They sold a solar kit, which included the panels along with virtually everything you need to DIY install. It was amazing. Down to some rags to wipe up glue. They even delivered and helped me get them up on the roof! The kit was around $2500 for 8 big Heliocol panels. Unheard of price. Still don't know why. Then about another $500 for plumbing and actuator stuff, so about $3K total + my labor. I really lucked out, and tried to send other TFPers to them for the same deal. But the co I bought them from no longer offers this deal (I checked recently).
what temps are you able to maintain vs outside temperature?
It's tough to say for sure, because there are so many variables and no way to create a good comparison test. I don't cover my pool, so my daily water temps are based on that day's sun exposure, the ambient air temp AND the temps of the night before. With no control for comparison, I can never be sure what the pool would have been without the solar. Kind of a catch 22. That said, my best guess is my system adds between 5-10° each day. If I bothered to cover my pool at night, I'm sure my results would be vastly better, but I've never tried. Nor have a ever turned on my gas heater (installed by the previous owners), so I can't help you with any comparisons there, either. My pool is usually about 10° warmer than the neighbor's, so that's about as scientific as I can get.
Yep, I was seeing upwards of $1K each when I was shopping. When I stumbled on my local deal I didn't hesitate.
I'm west facing with a screen so I feel like I'd need more panels than I otherwise would.
As I said, my panels face North, so I could use South for PV. My solar guy said it would make little difference, if any, because solar heaters are not subject to the same angle restrictions of PV solar. When I most need solar, in the swim season, the sun seems to be either directly overhead, or even slight on the north side, so I'm convinced he was right. In summer, my North side gets sun all day long. My house only has N and S facing areas, no W or E. The ridge runs virtual E to W.
Now West is a different issue, because you'll be missing that morning sun, which is instrumental in warming up the pool sooner in the day. You could always split the array, half West and the other half East. I've seen PV installations like that, when they don't have enough South-facing roof.
I'd really like to extend the swim season for longer and not have to use the gas heater unnecessarily
This was a disappointment. I'm getting the pool plenty warm in summer. I generally run the solar most of the day, but rarely want the pool any warmer than it gets. 85-90° is great for me. My thermostat is set for 85°, but a hot day can push it up to 90° or more, even after the solar kicks off. I'll swim in 80°, too. But the "promise" of extending the swim season a month on each end is a little thin. I don't get that, more like 2 weeks on each end, so an extra month total. Which is still nothing to sneeze at. In general, I feel my pool is about 5-10° warmer than it would be otherwise, and that can be the difference between getting in comfortably, or whining about it! Sometimes I'll swim in 75° or even 70°, if I'm overheated enough, so even in that season that's better than 65°! I don't have to consider the cost of running the pump for extended periods of the day to satisfy the solar system, because my PV system "pays" for it, not me.
If I'm going to spend nearly $10,000 on solar panels, is that really worth it to save $1k/yr vs gas
Though I've never tried, I think warming my pool would be more like $300-400 a month, x 6 months = $1800. To be fair, that guesstimate doesn't really matter, because I would never spend it. I get what I get from my solar and that has to do. $1000-2000/yr to warm up the pool is not in my budget. $3000 for 20+ years of an extra 10° was a no brainer for me and my budget. I don't enjoy swimming when it's cold, or even cool out, so heating a pool in early spring or late fall is also not in the cards for me. So, again, the solar heater is the right choice for my use case.
with penetrations in the roof
The Heliocol brackets do screw in, but they do not penetrate the felt or underlayment. I have a concrete tile roof, and the brackets are only screwed into the tiles, no deeper. I got that from the solar company that sold me the panels, and so far so good. So the array will not cause any roof leaks. The screws are sealed to the tile, but even if a seal fails the water will just drip onto the felt and run down to the gutter. An asphalt shingle roof would be a different story. We get decent wind here, too, but no issues there, either. I attribute that to the Heliocol design. They require no special tie-down straps like other systems do, and they're engineered for a healthy wind load (I forget the figures).
I hope I covered everything... (and then some?)
