Using a heat pump water heater to heat your home with a hydronic system is like trying to cool your home by opening the refrigerator door. A heat pump water heater pulls heat from the surrounding air to heat the water. Then you try to use that hot water to heat that same surrounding air you just pulled the heat from…

Heat pump water heaters don’t make sense in cold climates as they are pulling heat from air that you then have to heat via other means. Stick to gas/oil for supplemental heat or if electricity isn’t that expensive and it doesn’t get too cold you can just use a resistive heater. But that is typically much more expensive than gas/oil.