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Hot Water Heater Options

newguy101 Member Posts: 22
I currently have baseboard electric heat and propane conventional hot water heater. I am transitioning to baseboard hot water heat. I will be getting a Viessmann boiler with propane as the energy source. The contractor installing the system recommended I get a combi boiler.

I have also heard a lot recently about heat pump hot water heaters. There is actually a sizeable rebate in CT where I live for heat pump hot water heaters, which makes them cost around $300 or $400.

I understand that a combi boiler would save me money if it replaced my current conventional hot water heater. However, my sense is that a heat pump hot water heater would be even more efficient. Also, would it increase the life of my Viessmann boiler, since the Viessmann would only be used in the winter for the baseboard heat, vs being used year round?

My guess is that the cost of the heat pump hot water heater after the rebate will be in the ballpark of the increased cost of the combi boiler over the cost of a non-combi Viessmann. Could be wrong though. If that assumption is right, then the factors are – 1. Which option has lower operating costs, and 2. Which option has the potential to last longer without needing replacement.

What do you guys think? Thanks!


  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 3,931
    edited February 2020
    I like the Viessmann 222-F combi, but it sounds like the heat pump will save you money in operating costs.
    Combi boilers are more complicated, so there's more to go wrong although we've installed three of them in the last two years without any problems being reported. Still, the heat pump would be my choice if you have the room.
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
  • Jamie Hall
    Jamie Hall Member Posts: 22,888
    I'd go with a straight boiler, sized properly to meet the heating load of the house (do a heat loss calculation!!!). Then a hybrid or heat pump water heater. That will give you the best overall energy efficiency.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,646
    Heat pump water heater would get my vote as well. Here in Maine, we have a $750 rebate as well which brings the cost of a new unit to less than a standard electric water heater. Heat pump water heaters (HPWH) do require some maintenance though. Have to keep the coils/air filter clean. And they do require a condensate drain, if the area you want to put the HPWH has a floor drain then you are in business, gravity always works! But if you dont have a suitable drain that is lower than the unit, you will have to get a condensate pump, for that matter same goes for your new boiler, so they can share either the pump, or a drain if available.
    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
  • newguy101
    newguy101 Member Posts: 22
    Thanks so much for the quick replies! Looks like there is a consensus.
  • ethicalpaul
    ethicalpaul Member Posts: 5,577
    edited February 2020
    I’m loving my new heat pump water heater. You can find my discussion thread about it I think by clicking my username. NJ gave me $750 for it

    Edit: here it is: https://forum.heatinghelp.com/discussion/170260/dhw-gas-vs-hybrid
    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el