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Need some help sizing a room up.

We remodeled a large bedroom with an enormous column radiator with 16 sections. The room was always way too hot with this guy even with the smallest vent I could find. I am looking to size the room for a new radiator and wanted some guidance for how many BTUs I need. Room is first floor and north facing. Measurements are 16 feet x 12.5 feet x 9 feet ceilings with 2 windows. Walls are brick cavity. Many of the calculators I find online give me varied answers ranging from 4500 btu to 8000. Any thoughts ?


  • Jamie Hall
    Jamie Hall Member Posts: 22,901
    Somewhat tricky

    determining the heat loss from a single room, that is.  Questions that spring to mind -- what's above it?  Is that space heated?  To what temperature?  Is only one wall exposed to outside?  Which one?  Or is it a corner room?  What spaces are beyond the unexposed walls?  Are they heated?  To what temperature?  What is beneath?  Etc.  One can come up with quite a range of numbers...

    At which point, the perhaps obvious question arises: you have a radiator in there which is clearly capable of heating the space.  It sounds (you mention a vent) like single pipe steam.  Have you thought about putting a thermostat controlled vent on?  They come with both local and remote thermostatic control, and allow one to control the room temperature quite closely.  They are a LOT cheaper than a new radiator... and much easier to install!
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,576
    edited October 2011
    room too hot

    is this in a house, apartment bldg, remodeled warehouse loft?

    if it is the same radiator, in the same room since being built, i would assume the radiator is the right size for the heating load, as the dead men were pretty good at heat-loss calculations.

    various causes of an over-heating radiator could be:

    1.over-pressure making the temperature of the radiator too hot.

    2.bad main venting, causing that radiator to get hotter quicker, instead of all heating simultaneously.

    3.improper thermostat location/setting/anticipation.

    you could try a trv on this rad as well if the above corrections do not solve the problem.

    when you determine the cause, and correct it, you can probably burn less fuel too!--nbc
  • Haviara
    Haviara Posts: 30
    The room was changed.

    Thank you for all your responses and input

    The room has 3 exterior walls and heated rooms above and below (House is a two family building). It is also the room on the north end of the home. My pressure and main venting is great and all other rooms in the home are good. This room appears to be overheating because it was changed since being built with the addition of a large closet and removal of a window. The current radiator is 11520 btu. I was hoping to replace with a smaller tube radiator as the existing guy takes up and enormous amount of space. I was thinking that a 12 section tube radiator would take me to 8,640 btu and still provide enough heat energy for the space.
  • JStar
    JStar Member Posts: 2,752
    edited October 2011

    What city/state do you live in?

    How many square feet of windows? Doors?

    What type of windows, doors?
  • Haviara
    Haviara Posts: 30

    I live in Brooklyn, NY. There are 2 double pane aluminum windows that are about 12.9 square feet ( The third was removed.) There is also one pine door to the room.

    Thanks again,
  • Haviara
    Haviara Posts: 30
    Any Ideas?

    I'll take any guidance? any Ideas?
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