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too big of a boiler bad?

wingit Member Posts: 2
Chicagoland area. 60 yr old 1100 sq ft ranch. Brick exterior. Old windows but plan on replacements within 6 months. Plan on adding blown in insulation. Currently unfinished but plan to finish basement (same size as house)

It currently has baseboard heating. Also has the above boiler. I plan to rip out the baseboards and put in radiant floor heating. Is this the right size or is it too big? Is it bad to have it too big?



  • Jamie Hall
    Jamie Hall Member Posts: 16,609
    The only proper way to size a boiler for either radiant or hot water heat is to determine the heat loss for the structure first. That is what the size is based on -- so the thing to do is to determine you heat loss, based on the improvements you want to make.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Paul48
    Paul48 Member Posts: 4,470
    I think that removing the baseboard would be a huge mistake. Leaving it provides the over-radiation for a future mod/con. You need the help of a skilled designer.
  • hot_rod
    hot_rod Member Posts: 14,871
    If you want radiant heat, a careful design and plan is essential. The type of radiant application, building loads, floor coverings, controls, and your expectations are all part of the plan.

    Radiant is the best heating method in my book, properly done of course. Panel radiators are another option, great for sleeping rooms or supplement to radiant areas.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    Steve Minnich
  • Zman
    Zman Member Posts: 6,792
    That boiler is absolutely at least 3x to big for any house that size and that is not a good thing. Boilers have lower efficiency and shortened lives when oversized.
    As mentioned above, do a heat loss calc on the house and design your radiant right the first time.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • wingit
    wingit Member Posts: 2
    I plan on hiring someone to do the work. I just don't like not knowing anything when talking to them so I tend to over research stuff.

    Jaime & hot rod - I would assume the contractors coming in will do that.

    Paul48 - "over-radiation for a future mod/con" no idea what that means. Why would it be a bad idea?

    Zman - I am purchasing this house. The boiler was installed 2 yrs ago. It may shorten it's life span but I would rather spend that money later than today since I am sinking a ton of money in it even before I move in.

    So if I understand this right the only downsize is a shortened lifespan.
  • hot_rod
    hot_rod Member Posts: 14,871
    Find a contractor that does the load calculation and design, and questions you about your needs and wants. No, not all take the time to do a proper calculation.

    Fuel cost may be higher on equipment that cycles frequantly.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream