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D.O.E.Capacity or I.B.R?

mjj_2 Member Posts: 22
A little bit of education is indeed a dangerous thing. In the process of picking a contractor to replace the old hot-water oil boiler in our 80-yr-old house CI-heated house,I'm contemplating 3 heat loss numbers. 77,280 BTU's calculated by one contractor, 97,850 by an energy audit rep. and 94,900 by me with HVAC-Calc (which apparently doesn't have a buffer-factor). None of these include the unheated basement.
My question is: should I be matching the heat load to the D.O.E. heating capacity or the IBR ratings? Our mains are insulated with intact asbestos.
Any advice is appreciated


  • In my opinion

    stay with the lower #s, these are based on worst case scenario for your area so you will be fine.

  • Brad White
    Brad White Member Posts: 2,398
    I agree with Dave

    I=B=R ratings add 15% fat in what is probably already an oversizes system. You are not likely starting from a dead cold start. Use the DOE or AGA gross output number. It can save you a boiler size.
    "If you do not know the answer, say, "I do not know the answer", and you will be correct!"

    -Ernie White, my Dad
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