Well, I have about 2/5 coverage ( 640sq ft pool, 240 sq ft panels==> 37.5%) and today, the Saturday of Memorial Day weekend, here in Northern New Jersey, my pool is 90 degrees! I can get 8-10 degrees of increase when I use them full blast.

That's despite having a nasty, rainy month of May. When we have a nice sunny 2nd half of April we'll be in the mid 80's by early May and swimming. We can only extend our swim season when the weather cooperates, but my opinion is that when the weather stinks, who wants to swim anyway?

As I said, I preach heresy on this!