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Help figuring out EDR

Hi everyone, I'm totally new to figuring out anything related to steam heating. I'm looking to replace my current oil boiler, so I've been reading as much information online as possible about it. I always thought a boiler was just picked based on the size of the house.

I have been getting quotes to replace my boiler, but now I want to make sure it's sized properly and I kind of trust myself to care it's sized properly than random plumbers. I'm trying to figure out if what I'm doing is correct, I downloaded a pdf someone posted here entitled "Sizing to standing radiation" and i measured each radiator based on the type of radiator, height and number of sections

This is a 2 family, 2 story, not very large home.

For example, I have one living room radiator that is "type 2 tube", which is newer than the "old style" radiator, but is not one of the "thin tube" models.

 I measured it 9.75" wide and 26" height, from the chart I see 4.0, so I multiplied that times 13 sections and got 52 sq ft of radiation

If that logic is correct, I did all my radiators and got a total of 245 sq ft, then multiplied by 240 for steam, for a total of 58,800 total BTUH load.

Does this seem correct so far? Does this mean I just need to pick a boiler that is around 58,800 btus?

Thanks for any help here,


  • Jamie Hall
    Jamie Hall Member Posts: 23,272
    Certainly on the right track

    but.... most steam boilers (if not all) are sized not only in BTU but in EDR.  It is much easier to match sizes using the EDR rating -- which takes into account such things as pickup factors -- than to play around with converting EDR to BTU and then worrying about pickups and all that.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • vaporvac
    vaporvac Member Posts: 1,520
    Recent post!!!

    To add to what Jamie said, here's a recent post that shows examples. I referred to my own boiler choice so you can see the actual boiler charts. Hope this helps. colleen

    Two-pipe Trane vaporvacuum system; 1466 edr
    Twinned, staged Slantfin TR50s piped into 4" header with Riello G400 burners; 240K lead, 200K lag Btus. Controlled by Taco Relay and Honeywell RTH6580WF
  • NewbieInQueens
    NewbieInQueens Member Posts: 25
    Got it

    thanks for the replies so far, but was hoping someone could also confirm that the process I'm using to measure the sq footage of the edr is correct.

    On another note, can anyone recommend a heating specialist that could do my oil to gas conversion and services the Queens, NYC area? I've reached out to most on the "find a contractor" with no good results,

  • Jamie Hall
    Jamie Hall Member Posts: 23,272
    Don't look by Zip

    Look by State and Town.  There are at least a dozen who serve Queens...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    ALIGA Member Posts: 194
    contact Jstar

    Thatcher Heating, he is on the forums. Highly recommended and services Queens.

    What part of Queens are you in? I am in Jamaica.
  • NewbieInQueens
    NewbieInQueens Member Posts: 25
    Thanks for the suggestion

    I have reached out to him, I am in Astoria. Hopefully it works out :)