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Energy Output with Missing Radiators

csmythcsmyth Member Posts: 2
I am trying to understand a fundamental question. After reading for several years on this forum and reading Greening Steam, I still can't understand this.

We moved into a place 4 years ago that was abandoned. 2 of the radiators were missing and we haven't replaced them. 1 radiator is in a room we choose not to heat, so we just closed the valve. Then we put a freestanding wood stove in one of the rooms with a missing radiator.

My question is, if I put a radiator back into one of the rooms, will this cost more in fuel?

Basically, will the addition of a radiator unit add to energy consumption. I assume it will add to a more even heat through the house which is somewhat of a hope.

One pipe steam (with the weird two pipe on the first floor)
Weil Mclain EG 65 (or 75 I can't remember now)
5 radiators on 2nd floor
3 radiators on first floor (thinking of adding one more back in)
No vents on the mains in the basement.

Am I currently overburdening the unit by not have enough radiators? Will an additional radiator make it more efficient? I know this is sometimes true of Forced Air, if you do not have enough pipes to dump the heat then efficiency drops.

Any leads to other principles or ideas I need to understand to make an intelligent choice about this would be much appreciated!

Thanks all for keeping this community going, I've learned so much by reading the past few years.


  • Jamie HallJamie Hall Member Posts: 12,696
    Basic answer: yes, it will use more fuel. You are adding heat to the house, after all, and the heat has to come from somewhere. However, how much more fuel it will use is by no means obvious, and there are really too many variables to give a solid answer. Just for starters -- how warm is the space now? How warm will it be? How much heat is being transferred in from other spaces? Or might be being transferred out with the new radiator? Does your boiler cycle frequently on pressure now? With the new radiator, it will cycle less often -- but how much fuel that will save is the subject of lively debate.

    And so on...
    Br. Jamie, osb

    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.

    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • KC_JonesKC_Jones Member Posts: 4,399
    Also adding venting to the mains (something you should do no matter what) could offset the increased fuel consumption or possibly even lower it.

    As Jamie said so many factors it's really hard to say.
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
  • csmythcsmyth Member Posts: 2
    Thanks all, these are really helpful suggestions.

    I am mainly checking on the idea of what the capacity of the boiler is and how much steam can fit in the volume of pipe that was planned for. I haven't been able to understand if there is half the volume, does that change the efficiency of the boiler unit.

    Jamie, good point about surrounding conditioned space, I think for this reason it would be efficiency neutral. Yes, more fuel, but less "fuel" being drawn from the adjacent room with a radiator.

    KC, guess I need to get a boiler guy on putting main vents in. Any idea a cost range for that?

    I think when we redo the kitchen (who knows) we will add a radiator back in to that room.

    Thanks for your insight!
  • KC_JonesKC_Jones Member Posts: 4,399
    csmyth said:

    KC, guess I need to get a boiler guy on putting main vents in. Any idea a cost range for that?

    We don't discuss pricing on this site.

    If you let us know your location we may be able to recommend a good steam contractor.
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
  • nicholas bonham-carternicholas bonham-carter Member Posts: 8,123
    Installing adequate main vents may pay for themselves in a few months with the lowered fuel use. It’s a case of pay now or pay more later-month by month by month, until you put them in.
    With no main vents, the boiler is forced to squeeeeeeze the air out of the constipated little radiator vent openings, instead of pushing out lightly the air through the bigger main vents.—NBC
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