With the var speed heat pump I also have a variable speed air handler for the home. What that means is my home heat pump and air handler are almost always running, but in low speed. So during the warm half of the year when I duct the cold air by-product from the water heater to the floor of the closet the water heater is in, where there's a new air handler for my home HVAC. No matter what time of day the water heater runs to heat the water tank (and produce free cold air), the home HVAC is always running to take in that free cold air and distribute it through the house.
Thanks, definatrly gonna look into those heat pumps and air handlers. Would be nice to get rid of the jet engine house fan, or use it only seldomly.