Dual-fuel high-efficiency natural gas / heat pump systems?
Does anyone have any experience with or thoughts on the hybrid “dual fuel” natural gas furnace systems that are combined with an air-sourced heat pump (instead of an AC only unit)?
The intent is for the heat pump to provide heat when its most efficient, but then switch to gas when the outside temperature drops to the point where the heat pump is no longer efficient or effective.
I am planning a house in SE Michigan (zone 5), and this seems like a potential option. I am also considering a multi-split system, but I have not found a multi-split system that is effective below 5 deg F. If I go multi-split, I will need to have some sort of back up – probably electric resistance.
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