Solar for our 14x30 / 7500 gallon pool was $4400 1.5 years ago. Works great.

You might want to consider a pool water heat pump.

My 145,000 BTU heat pump runs about 20 hours to initially raise the water temperature from 65 to 85 degrees in my 15,000 gal. in ground, gunite pool On average, It runs approximately one hour daily to recover the 4 to 6 degree (depending on the time of year) water temperature drop overnight.

Bigger is better. I found a 94,000 BTU heat pump cost more to operate because it ran much longer then a 145,000 heat pump which ran less to increase the water temperature initially and less time to recover the overnight water temperature lost.

A vinyl cover will reduce the overnight water temperature loss by approximately 70%. After one season, I stopped using the vinyl cover because the inconvenience of removing the cover every time I wanted to use the pool was not worth the cost savings.

Everyone I know who used a roof mounted solar heater did not replace the solar heater after they replaced the roof. Many had roof damage caused by poor solar panel installation.

Jack’s Solar (352) 267-4903. Quality work, competitive prices, ten year warranty!

The math just doesn't work out for a solar heater for a pool. I'm an engineer, and spent considerable time researching it prior to my pool installation. Solar heating works great when you don't need it (full summer), but can't keep your pool at a reasonable temp (for me that's 85+) during the cold months. It will help warm your pool in the spring and fall, but it's slow, and you may or may not get the temps you want.

Most people that get a solar heater also get a backup heater to assist during spring and fall and take over completely in the winter. I have a heat pump (get the biggest you can find - currently 144K), and during the coldest months it raises my electric bill $30 or so. That is for a month of heating! Note: I would always recommend a heat pump over a gas heater with regards to cost here in Florida - it's not even close. The only reason to get a gas heater is if (1) You have natural gas, (2) You have a spa connected to the pool that needs to be heated quickly, and/or (3) Your pool is extremely large (20,000+ gallons).

When you consider the investment of a solar heater (~$5K), and the fact you need another heater anyway to supplement it, you have to ask yourself:

"What is the payback of $5K vs the $30/month electric increase if I just use the heat pump?"

Keep in mind, that $30/month is only during 3 months of the year. Another 3-5 months will be in the $15-$20/month range, and $0 for the 4 hot months.

I have a lot more details, but the short story is you are better off with just a heat pump for consistent, reliable heat.