Click here to Find a Contractor in your area.
Welcome! Here are the website rules, as well as some tips for using this forum.

If you've found help here, check back in to let us know how everything worked out.
It's a great way to thank those who helped you.
Need to contact us? Visit

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

mjj_2mjj_2 Posts: 22Member
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_166Brad White_166 Posts: 2,391Member
    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 right!"

    -Ernie White, my Dad
This discussion has been closed.


It looks like you're new here. If you want to get involved, click one of these buttons!