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Buying home with hydronic radiant floor heating--what should I look for?

rmittmanrmittman Member Posts: 4
edited July 2019 in Radiant Heating
I'm contemplating purchasing a 1996-built home with a hydronic radiant heating system in concrete floors. It's located in Napa, California--mild climate. I have a lot of questions:

23 years later, what should I be looking for? What typically could go wrong/be broken?
What type of contractor should I hire to inspect the system? Any recommendations in the SF Bay Area?
What kind of maintenance should I anticipate doing on the system?
Is there any special treatment for replacing carpeting or installing tile?
Is it possible/desirable to install a chiller to provide cooling?

Thank you for your expertise!


  • Jamie HallJamie Hall Member Posts: 14,720
    Usually those things are pretty bulletproof -- except the boiler. If it's the original boiler, it may be coming to the end of its life. Also the pump or pumps.

    The controls are probably obsolete now, but if they work...

    Maintenance is minimal, but necessary: check the condition of the water, mostly. Make sure the expansion tank is working... that sort of thing.

    Changing the floor covering -- particularly to thicker wood or especially carpet -- makes a big difference on how well (or not) it can heat.

    Cooling the place through the floor just isn't an option. There are much better and more flexible ways to do that -- central air, minisplits, etc.

    Ideally you would have someone knowledgeable take a look at it -- and as it happens there is a man in Berkeley who is very good: @Alan (California Radiant) Forbes . Forbes Plumbing, 510.559.3575. If he is too busy, I'm sure he can suggest someone for you. Be sure to tell him how you got his number!
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.
    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
    Alan (California Radiant) ForbesJean-David Beyerrmittman
  • STEVEusaPASTEVEusaPA Member Posts: 4,712
    edited July 2019
    One thing you can do, is have someone with a thermal imaging camera fire up the heat and check the slab for possible leaks.
    See if the system is holding pressure.
    See if there are any signs of leaks/corrosion around the manifold or circulator flanges.
    The boiler can be checked for leaks/corrision, combustion tested, etc.
    If you're redoing the carpet, do the same thing with a thermal imaging camera to see if any tubing might be in a spot where someone could damage it with tack strips. If you're ripping up tile, no saw cutting, chip it clean (I know, labor intensive).
  • hot_rodhot_rod Member Posts: 14,362
    determine what type of tubing is in the floor. There are some brands and versions that were problematic, at least one class action suit is still open.

    Alan noted above or Bill at Bay Hydronics are two names that come to mind.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • nibsnibs Member Posts: 462
    If the radiant floor is working properly you will love it.
    You are about to spend thousands on a house, spend hundreds to get a professional report, the seller should at least help to pay for any repairs needed.
  • rmittmanrmittman Member Posts: 4
    Thank you so much, @Jamie Hall , @STEVEusaPA , @hot_rod , and @nibs ! This is exactly what I was hoping to hear.

    @hot_rod, what brands of tubing should we watch out for?
  • ZmanZman Member Posts: 6,288
    Take a lot of pictures and post them.
    Entran 1 and 2 are huge red flags.
    Entran 3 and grey polybutyle have had bad press and can get unwanted attention from home inspectors.
    You want to figure out what type you have and whether it has an O2 barrier. Make a note of how many loops you see compared to the square footage of the space.
    In the '90's some contractors had radiant dialed in, others were still leaning lessons the hard way.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • hot_rodhot_rod Member Posts: 14,362
    Also look for Kitec or Warmrite brand in the plumbing or radiant piping.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • rmittmanrmittman Member Posts: 4
    @hot_rod , are those two good or to be avoided?
  • ZmanZman Member Posts: 6,288
    rmittman said:

    @hot_rod , are those two good or to be avoided?

    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Alan (California Radiant) ForbesAlan (California Radiant) Forbes Member Posts: 2,618
    edited July 2019
    Being in Napa, your system could have been installed by Warm Floors. They are also in Napa.

    We don't see much Kitec or Warmrite around here, but Entran and polybutylene are a presence. Warm Floors is famous for using non-barrier tubing. Not the end of the world; you just have to make sure your boiler and components are compatible.

    Take some pictures of the boiler, piping around the boiler and manifolds, if you can get to them. If there aren't any manifolds in the mechanical room, you can find them behind access panels in bedroom closets. Post them here so we can see what you have.
    Often wrong, never in doubt.

    Click here to learn more about this contractor.
  • rmittmanrmittman Member Posts: 4
    Thank you, @Alan (California Radiant) Forbes . I'll check with the architect who built the house about the contractor. And thank you for the offer to look at photos of the system. There are manifolds in the bedroom closets.

    To everyone who has commented, I have to say I'm blown away by your generosity and engagement.

    I've always wanted radiant floors--I thought they'd feel great. Your comments confirm that. If we manage to buy this house, I guess we'll have that chance.

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