Pool temp

[chem geek]

My wife uses our pool for exercise therapy so we keep it close to 88F. We've had to use gas for some days the past week or two -- mostly going from 84F in the morning to 86 or 87. The solar takes it to 88 or 89 by the end of the day, but then we lose about 4F overnight (during earlier summer, loss is only 3F overnight). We have an electric opaque safety cover which helps reduce heat loss, but by only around half of what a true solar cover would do.

We'll probably go between solar and gas through October and perhaps into one or two weeks into November, but then it gets way too expensive and the air temperature gets too cold for swimming as well. She'll then use an indoor pool at a local community center where the elastic in her swimsuits will deteriorate in just one season (no CYA used in the indoor pool and around 2 ppm FC). It costs around $3.50 per hour to run the gas heater (250,000 input; 200,000 output) -- not very efficient so I may replace it with a heat pump IF it makes sense to heat the night before with air temps of 55F heating the water to 88F (so a 33F rise -- seems kind of high to me so maybe the heat pump won't be that efficient?). Also, our electric rates are high -- around 32 cents/KWh.

Richard