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Sizing boiler for remodeling.

Planning new radiant heating system on the ground floor for our home. The house was built in 2005 by US Homes. Our house has forced warm air on both floors, two separate systems. My question is for the first floor, for radiant heating could I use the size of the furnace for the sizing of the boiler for radiant heating?


  • SWEI
    SWEI Member Posts: 7,356
    In a word, no. Someone needs to perform a room-by-room heat loss on the structure. Where are you located?
  • Thinking
    Thinking Member Posts: 3
    Why would another heat loss need to be done?
  • SWEI
    SWEI Member Posts: 7,356
    Do you have the heat loss calculation from the original system?
  • Thinking
    Thinking Member Posts: 3
    Yes, we are putting hardwood floors in two rooms that were carpeted. I didn't think the manual j changed btus when selecting heating type.
  • Zman
    Zman Member Posts: 7,569
    So,here is the part you are missing. I guarantee no one from US Homes ever did a heat loss. Even if they did, the furnace was likely just rounded up to the next size in whatever brand was giving them the best price.
    It takes so little time to do a heat loss, why not just do one?
    Over sizing boilers and circulators is a huge waste of energy.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Rich_49
    Rich_49 Member Posts: 2,766
    NEVER , I repeat NEVER did US Homes or Lennar or Centex , K Hovnanian, Pulte perform a PROPER heat loss calculation for any home they ever built save for a rule of thumb number . Bigger is better and if it aint well , too bad . Was , is and will continue to be the norm . Even their energy star homes are piss poor excuses for something called energy star . Where are you located ? I suggest using the find a contractor feature and locating someone relatively close to you to assist . Maybe even myself if you are in Jersey . Hell , we were one of the largest markets in the country through the 80's into 2000s . Ocean and Monmouth county especially .
    You didn't get what you didn't pay for and it will never be what you thought it would .
    Langans Plumbing & Heating LLC
    Serving most of New Jersey, Eastern Pa .
    Consultation, Design & Installation anywhere
    Rich McGrath 732-581-3833
  • Bob Bona_4
    Bob Bona_4 Member Posts: 2,083
    Plus, a radiant heat loss calc will have different values than a Man J. Usually lower, and possible supplemental heat needs are revealed, floor loading, etc etc.