Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Steam boiler sizing

Joe Blanks
Joe Blanks Member Posts: 10
Question for the experts out there....just quoted a gas/steam boiler replacement for a 5,500s.f. house.  The installed radiation was calculated (measuring rads) at 1,050 s.f.

A competitor got the job with a boiler that provides net IBR of 700 s.f.  because, of course, my price was too high. 

I know what will happen...but curious as to what the specific problems, other than the obvious, this customer might have this winter.  Is it only going to be noticeable on the really cold days?  Might the heating gods be unkind and this guy will get away with this installation?


  • DanHolohan
    DanHolohan Member, Moderator, Administrator Posts: 16,288
  • Joe Blanks
    Joe Blanks Member Posts: 10
    i see...

    Thanks, Dan.  It makes sense.  So in reality....chance are that this customer will say "see I told you so, that other contractor was trying to sell us a big boiler we didn't need," and they will seem correct, even though my system would have saved them money.  I guess the satisfaction will be mine alone of knowing I could have served them better.  It's lonely at the top of Olympus.
  • Charlie from wmass
    Charlie from wmass Member Posts: 4,253
    why they can get away with it unscathed

    The boiler ratings also have pick up factors in them. I have had one boiler sized by my supply house and they did not add a proper pickup factor to the size of the boiler. They insisted it was already built into the rating. This was when I was young and dumb and listened when my elders spoke. The boiler heats the house and the owners saved a lot of fuel compared to the old boiler. They could have saved more and that last radiator would have heated all the way across and the steam vent would close on it if I had one more section. But it never does the thermostat shuts off before that last section ever gets hot even on the coldest day. They thing is if they undersized the boiler they may do other things wrong then you can go back and install the right boiler with the right pipe work. clear a spot 4 years from now to do it.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
  • DanHolohan
    DanHolohan Member, Moderator, Administrator Posts: 16,288
    Down the road,

    show 'em that story. Sometimes it helps to hear it from others.

    These folks will never know what not hiring you cost them, but lots of people will read this post, and you'll get those. Print it. 
    Retired and loving it.
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,573
    small boiller

    if only those [potential] clients of yours could have been directed here for information, and maybe a copy of "the lost art of steam heating".

    most likely, the winning bidder will not make any provision for air removal, and so the gas company will be paid to squeeeze the air out for each firing. however, since the boiler will run 24/7 due to mis-sizing, maybe that won't be the major problem!--nbc
  • DanHolohan
    DanHolohan Member, Moderator, Administrator Posts: 16,288
    A suggestion.

    A number of good contractors give perspective customers a copy of my book, We Got Steam Heat, along with the quote. They urge them to read before they decide and this usually makes the difference. They do so well with this book that we offer it in a ProPack:


    Something to consider.
    Retired and loving it.
  • Dan, you knew I couldn't resist.....

    For my alternative perspective on boiler sizing, look here http://www.heatinghelp.com/article/11/Hot-Tech-Tips/1551/Taking-Another-Look-at-Steam-Boiler-Sizing-Methods-by-Dave-Boilerpro-Bunnell

    Similiar principals apply to two pipe, but can be implemented more easily.
    The Steam Whisperer (Formerly Boilerpro)

    Chicago's Steam Heating Expert

    Noisy Radiators are a Cry for Help
This discussion has been closed.