Thank you, Douglas we are paying today in Summer approx $250.00 a month, in winter is cheaper (approx $200.00), my husband calculates in summer only for the SPA (in 12 grades F), and the extra cost is approx $50.00 only to increase the temperature. Once is heated the electricity going down. Maybe I'm wrong, but the idea to heat the pool is only to do when one customer wants it. So, if the guest wants this service, I really don't know yet how much is the average for this cost. Maybe trying out this next winter, and will see. Thanks again for helping me.