I'm considering adding a small hydronic heating system to my addition (<1000 sf) and am considering using a hot water heater as a supply. I'd like to use one unit for both hot water and heat due to space reasons. I currently have an A.O. Smith high efficiency unit. However, it is extremely loud with the blower. Due to it's location it is a real problem as it's off the family room.
I've seen a few option that claim to be very quiet such as Polaris and Heat Transfer Product's Phoenix. Both are very expensive but look quite robust. Anyone use either of these products or have any other suggestions?