Our pool is between two tall homes and is shaded for all but 3 hours a day Normally you can’t swim in our pool until June because it’s just to cold (68F – 75F). I like swimming in about 80F to 85F myself, if it’s sunny and warm out. I created a prototype heater coil that seemed to work for its size. I then create a large heater coil out of 180 feet of copper tubing that connects to my pool pump using a garden hose and fits inside the grill. The hose runs from the pump through the grill heater coils and then into the pool. I heated my pool from 68F to 89.4F in 48 hours using 3.5 tanks of propane.