I still have not made the move to heat my pool - in Southern Ontario Canada. this will be my full year with a renovated pool - new liner and all new plumbing for in ground pool - so hopefully no leaks, so I do not have to refill the pool constantly .. (crossing fingers).. I have a smaller pool - 14 x 28 feet - now with a shallow end - so I think my volume is just over 8000 gallons.. are Heat Pumps worth it - if I never had a heater before. this is for the family - as I grew up just diving and not care about temperture - but I am hoping that they will use it if I can get the temp up for them. I am thinking of expanding the swim season - I can't imagine my family jumping mid April or late October.. just your typical May 24 to Labour day- ish.