I second Matt. The time, space and hassle involved to get noticable heat from a home brew would be more than offset by purchasing a nice 4x20 or even 2 4x20s. Nice, compact (compared to home brew systems), ready to go and REAL heat. I don't think anyone can argue that Matt is pretty far north and living in the Nation's Icebox here in Northern MN, I can vouch for the effectiveness and convenience of a nice purchased panel system. Less than $300 and our pool is nearly ALWAYS at 82-87 degrees.