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Like to replace existing antique 3 tube and fin radiators in my old house but I’m not sure how many BTU’s per foot they produce.

JamesRMillar | Posted in Energy Efficiency and Durability on

Attachment shows 2 tube, 3 tube, and 4 tube (I’m not even sure what this style is called). I have the 3 tube arrangement throughout the house and I would like to be confident that when I upgrade, I’m getting more heat for each room in this 1650, modestly insulated, house.

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  1. GBA Editor
    Martin Holladay | | #1

    If you take off the cover and examine one of these radiators, do you see any marks to give you a clue? Perhaps a manufacturer's name?

  2. Expert Member
    Dana Dorsett | | #2

    Those are the innards of cabinet type convectors. As shown in the picture they are rotated 90 degrees from how they sit in the enclosures.

    If you measure the height & widths of the fins, and count the number of fins, and measure height & width of the enclosure they were in you can probably find a spec on a similar convector product. eg:

    They are often specified for 215F steam and 200F entering water temperature (EWT), but the output can be inferred at other water temps:

    At 180F EWT the output is about 80% of what it is at 200F EWT... 140F EWT it's about 40% of the 200F EWT output spec...

    ... at 125F EWT (a good condensing boiler temp) it's about 25% of what it puts out with 200F EWT

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