I was excited to find this product as a cheap alternative to a pricy gas heater, and bought it. The price was cheap enough, but then I spent the same amount again buying a bunch of diverter valves and plastic hoses, so I could divert water from filter through the SunHeater when the sun was shining, and bypass at night and when overcast. I even built a home-made 20 foot stand out of 2x4's so it wouldn't just sit on the ground and would have a better angle to collect the sun. I didn't have any problems with the product itself, but I live near Boston, MA, and it's just not a very sunny part of the U.S. Couple that with my back yard having trees near my pool so even if it is a sunny day, sun won't hit my backyard until around 10:30am, it just never warmed the water enough for me. I have it connected to my 15 foot above ground 4 foot high pool, so I think one panel should have been enough. I ended up with hoses all over the ground and diverter valves hanging with bunji cords off the sides of the pool and filter, a huge 20 foot panel on a home made 2x4 bed, and just no where enough sun hitting the panel for me in my area. I am going to bite the bullet and pay around $600 for an LP gas heater this year. This way I can guarantee when I have a birthday party or cookout with kids coming over, I will know cloudy or whatever, that my pool will be warm enough for everyone to take a dip. After all, as a scardy-cat adult I only go in when the water temp is 80+ and without a heater in my area with my backyard I am lucky if this happens ONCE the entire summer where I can catch a dip.