[QUOTE=Spensar;64775] Otherwise, they don't do much for the pool temperature in a moderate or northern climate.

Spensar,

I don't know what you consider a moderate or northern climate but I can assure anyone that here in the northeast they do make a big difference as those tables in the links will confirm. Nights are usually quite cooler than the water and they do help retain any heat you gain during the day. Heat is heat whether it is obtained naturally from just the sun on the pool or by fossil fuel or heat pump. Am I missing something?

Al