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Unico heat pump vs radiators

Hi. We recently moved into a historic home (early 1800s) in the DC area that has a Unico small duct high velocity AC unit and a gas boiler with water radiators. The boiler and some of the radiators are not in great shape and likely need to be replaced. The decision we are trying to make is whether or not to replace the boiler and radiators or remove the radiators all together and instead heat the house via a heat pump using the small ducts already in place. For reference the house is around 1700 sq feet and has a mix of original (ie single pane) windows and newer double pane windows.

I assume that radiant heat is likely going to be our best heating option but removing all the radiators would give us a lot more floor space, I'm just concerned that come winter we are going to regret getting rid of the radiators.

Thanks for any advice and sorry if this is a dumb question. My knowledge of heating/cooling is limited and Ihave gotten mixed advice.


  • heathead
    heathead Member Posts: 229
    Foley Mechanical is a contractor in the DC area. He is well respected on this forum. The comfort level of the radiators will be far superior to that of the Unico warm air. I would think of it as it's 75 degrees at the beach, with clouds and no sun your feel cold. Then the clouds clear and 75 Degrees at the beach in full sunshine and it feels great. Post some photos of your boiler. The Radiators will give you the feel of the sunshine. This is of course a little overstated but has some truth.
  • Hot_water_fan
    Hot_water_fan Member Posts: 1,652
    Easy enough to replace the AC with a heat pump and try it for a winter. If it’s not to your liking, switch to the boiler. 
  • Steamhead
    Steamhead Member Posts: 16,479
    heathead said:

    Foley Mechanical is a contractor in the DC area. He is well respected on this forum.

    This. He should be your first call.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • pecmsg
    pecmsg Member Posts: 4,397
    Steamhead said:

    heathead said:

    Foley Mechanical is a contractor in the DC area. He is well respected on this forum.

    This. He should be your first call.

    Install heat pumps and use them for most of your heating needs. When the weather gets really cold 15°F or less (or when the heat pump is down) switch to the radiators.

    My BIL in Pa had a problem with his Thremo pride furnace, 2 days for parts to arrive. He was happy we installed a heat pump several years ago. Was still able to maintain 65° inside.
  • Lance
    Lance Member Posts: 257
    Consider this. A Unico system can be adapted with a hot water coil module and run off the hot water boiler. I have a home that requires 8 ton of coiling and only 90,000 btu of heat. I have two unico systems split equally. Oddly the first floor can heat the entire house for most of the season. the boiler also provides heat to three types of radiant floor tubing. IN floor, staple up, in slab all on a different temperature control from the hot water air coils at 170F-180F. Since Unico is high velocity stratification is not a problem. However noise in the quiet of winter will no longer be so quiet unless the outlets were sized properly. A common problem I have seen in Unico by others is the cheat the duct work to make a cheaper budget.
  • pnwdoc1
    pnwdoc1 Member Posts: 2
    Thanks to everyone for their replies. I'll reach out to Foley Mechanical and see what they have to say.