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Forced air heat pump with hydronic backup

axeyal Member Posts: 8
I have an existing Navien NCB-240 that currently uses cast iron radiators to heat (and supply domestic hot water) an old 2450 Sq Ft house in Michigan. The house does not have air conditioning.
I would like to install ductwork so that I can have AC. I would like to use a heat pump to heat the house (and cool it) for most of the heating season and use the Navien as an auxiliary heat source for when the temperature drops and the heat pump is less efficient.

I'm looking for advice on what heat pump manufacturer and model to use that can have a hydronic heat exchanger added to it. I see hydronic air handlers available but I'm not sure if they can be installed with a heat pump evaporator coil on top.



  • pecmsg
    pecmsg Member Posts: 4,850
    All of them. 
    The hydronic coil can go in the supply duct. 

    Use caution if the air handler is in unconditioned space to prevent freezing. 
  • Hot_water_fan
    Hot_water_fan Member Posts: 1,849
    Is the goal to remove the radiators? You can also just use them instead of a hydronic air handler.
    HVACNUT Member Posts: 5,841
    Why would you not use the radiators as auxiliary?

    Single story house? Will the air handler be in the basement?

    I know First Co., and I saw a Trane the other day that had the hydro coil in the air handler cabinet. But they can be easily added on the supply with a transition duct.
  • bburd
    bburd Member Posts: 918
    edited March 15
    If the radiator system is intact, keep it and wire it as back up/emergency heat, with the heat pumps as primary.

    You will never be as comfortable with a hydro air coil as you are with those radiators in an old house on a cold day.

  • yellowdog
    yellowdog Member Posts: 157
    Bosch and Ecoer both have heat pump condensers and air handlers you can add hydronic coils to.