Click here to Find a Contractor in your area.
Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit

Question on Navien

Hey Guys,

I'm getting quotes on a central a/c system with heat pumps that will replace a cast iron boiler system. Radiators were in way and I can't afford to do radiant and A/C. Using separate units for downstairs upstairs, air handler for top floor to be located in attic, first floor going in basement.

House is located in the Hudson Valley, NY. With this mild winter, I feel like I'd be served well by heat pumps, but it can get quite cold. Plumber has spec'd a Navien LP direct vent boiler to serve DHW needs (2 bathrooms) as well as act as backup heat source for those very cold days.

Do this seem like a reasonable plan? My concern is I know hot water for heat is typically separate from water used for drinking/bathing, any bacterial concerns with this setup?

Thanks in advance



  • Jack
    Jack Member Posts: 1,045
    Make sure

    That the hot water output on that unit is sufficient for the house. Combi boilers do not, typically, put out as much hot water as a straight tankless. I would suggest that you look at mini split heat pumps. You avoid the duct work expense, have " net to the space" higher efficiency H&C. It is extremely difficult as well as costly to add ductwork to a house.
  • Stuntmanmike
    Stuntmanmike Member Posts: 4

    Good point on capacity. Thing is I'm putting in duct work already for A/C (house is fully gutted right now). Other thought was putting in electric strip backup instead of LP combi, then getting a Voltex(?) heat pump water heater. Lots of options!
  • kcopp
    kcopp Member Posts: 3,818
    I would not....

    get rid of the cast iron radiators. You have great emitters why not use a mod con boiler and keep them. A/c can be done w/ a couple of mini-splits. Duct work in an old house will take up a lot of room and cut huge holes in the old wood work.
  • Stuntmanmike
    Stuntmanmike Member Posts: 4

    Radiators are already removed, full gut renovation that changed the layout of the house, lines cracked during jacking and most radiators were in the way. I'm definitely running A/C so duct work is going to be put in. Question I'm struggling with is, should i do the Navien LP combo or go with some electric backup for heat and an electric HW heater...
This discussion has been closed.