I was thinking of getting a heat pump to extend my swimming season for my planned pool. However, a local pool builder rep told me that heat pumps don't work well in my area because of the low humidity. Today is a fairly average summer day, and by the time the temp. drops to about 80 deg in the evening, the relative humidity probably rises to about 25%. Would a heat pump make sense in this case? It's not a very popular heating solution, most heaters are NG or solar in this area. If not a heat pump, then what would be the next best option?