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.

Cast Iron Radiators - Heat output

Bold_Eng1 Member Posts: 3
Hi I am working on a project to replace the existing cast iron radiators in a school in the city of Toronto. There is no labels on the units to help me find out the heat ouput, i was hoping someone on this forum would know. Any help would be greatly appreciated.


  • Bold_Eng1
    Bold_Eng1 Member Posts: 3
    here is little bit more information
    length:142 cm (56 inches)
    Height: 48 cm (19 inches)
    Width: 17 cm ( 6.7 inches)

    JUGHNE Member Posts: 10,567
    EDR is what you are looking for...equivalent direct radiation or the square feet of the surface of the exposed iron.
    There are plenty of charts to find this info.
    Somewhere on this web site.

    You have to count columns, sections and know the height in inches.
    Then if water the temp of the water, if steam the pressure at the radiators.

    Why the change out? It seemed there was always money better spent in a school building....just wondering.
    My school would need an upgrade in the boiler before considering this.
  • Jamie Hall
    Jamie Hall Member Posts: 21,105
    Those are pretty standard radiators -- as @JUGHNE says, there are tables somewhere around here. And... why are you changing them? Frankly, it's unlikely that anything else will be as efficient and simple...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    EBEBRATT-Ed Member Posts: 13,437
    Heat output will vary with the water temp
  • flat_twin
    flat_twin Member Posts: 338
    The chart I have says 6 column, 20 inches tall is EDR 3.00. There is no rating for 19" tall radiator.
  • Bold_Eng1
    Bold_Eng1 Member Posts: 3
    i didn't agree with replacing the radiators but its the school's mandate to replace the entire hydronic heating system including boilers and all the heating piping. The government needs to spend the money.
  • hot_rod
    hot_rod Member Posts: 19,273
    edited July 2020
    There is an ap for calculating radiators

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    JUGHNE Member Posts: 10,567
    Assuming they are also upgrading the thermal package of the building? If so then the heat load would drop. Often there was extra radiation installed.
    So room by room heat loss would be needed.