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Air to Water Heat Pumps

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Allislandradiant
Allislandradiant Member Posts: 41
in A-C, Heat Pumps & Refrigeration

Looking to install an air-to-water cold climate heat pump here on Long Island. This unit will be installed in a 3,800 sq ft home to heat a Radiant Heating system for three floors and provide domestic hot water. The customer is requesting an electric boiler as a supplement for the colder outside temperatures when the heat pump struggles. Does anyone have any recommendations they've used?

All Island Radiant

Comments

  • pecmsg
    pecmsg Member Posts: 6,238

    forget the electric backup with PSEG. Gas or oil only

  • GGross
    GGross Member Posts: 1,542

    I've used electro industries, argo, and Viessmann electric boilers. Electro industries has a wide selection of sizes and configurations

    https://electromn.com/#

  • tim smith
    tim smith Member Posts: 2,869

    I would wait until after 1st of year if you can. Daikin should release their unit they have put through UL & etc testing. Other one a buddy of mine installed at his place is steibel eltron and he is very pleased. They are proud of them $$$. His company does a lot of high end housing in seattle. Possibility. https://www.stiebel-eltron-usa.com/products/wpl-a2w-premium-climate-heat-pumps

  • Allislandradiant
    Allislandradiant Member Posts: 41

    Thanks for the info. It's challenging to obtain any information on this topic from manufacturers and fellow contractors who have experience with the air-to-water heat pump. They all claim that it works well in Europe with over 40,000 installations.

    All Island Radiant

  • Jamie Hall
    Jamie Hall Member Posts: 26,113
    https://forum.heatinghelp.com/discussion/comment/1858887#Comment_1858887

    At considerable risk of pointing out the obvious, Europe — all of it except parts of Scandinavia and Russia — has a very different climate. That said, there are even parts of the UK, for instance, where real life experience in older structures isn't very happy.

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Big Ed_4
    Big Ed_4 Member Posts: 3,229

    That's a system I would not consider on "The Isle of Long". Unless there is a fuel boiler back up. ..

    There was an error rendering this rich post.

    pecmsg
  • hot_rod
    hot_rod Member Posts: 25,236

    Low temperature radiant? Below 120 SWT makes a HP more viable. What is design temperature? Hours of occurrence? A zoned systems?

    A lot of questions to be answered before you can make a good decesion for them. Plenty of A2WHP systems operating in NY, Vermont, Maine and cold climates.

    Efficiency and output drops, but it can be designed around.

    Some A2WHP have electric back up included. I have the small Viessmann Vitocal 28,000 and it has a 6 KW (20,460 BTU/ hr) element built in. A dual fuel is not a bad option so you have a backup for heat and HW, if budget allows.

    How does LI temperature data compare to this example? If 0° is design in Syracuse, about 50 hours per year is at that temperature.

    You might snoop around the NYSERDA data base for installed HP data.

    Screenshot 2025-06-27 at 12.57.38 PM.png
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    Hot_water_fan
  • Hot_water_fan
    Hot_water_fan Member Posts: 2,195

    The R32 Spacepak looks great! But what is the owner doing for cooling?

  • DCContrarian
    DCContrarian Member Posts: 1,128

    Sizing a heat pump is much more complicated than sizing a boiler. When you're burning fuel, a BTU is a BTU. The performance of a heat pump depends upon the climate, the equipment and the building it's installed in. For a detailed look at the issues involved, I recommend this post:

    https://www.greenbuildingadvisor.com/question/how-to-model-and-predict-electricity-usage-for-a-heat-pump

    It's oriented around air-to-air but the issues are the same.

    Long Island, I'd guess your design temperature is in the teens, you're probably going to want a heat pump with vapor injection. I believe the Arctic is the only air to water currently available with VI.

    Domestic hot water is a poor fit for air to water heat pumps. Manufacturers offer it because people ask for it, but it doesn't work well. If you want to go all-electric get a heat pump water heater, compared to air-to-water the HPWH will use the same amount of space in the utility room, have lower or comparable operating costs, and cost substantially less to install.

    I'm not at all a fan of using a combustion device for "backup" heat. If the heat pump can't do the job, don't install it. Air to water is a poor fit for a backup boiler because the heat pump will have a modulating compressor that tries to sense the heating load. Having a boiler in the picture makes that sensing impossible.

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