Results 1 to 7 of 7
  1. #1
    Join Date
    Aug 2002
    Does anyone know the minimum opening size for combustion/ventilation air for a natural draft furnace
    located in an unfinished basement or crawlspace in TN?
    Is more than one opening required? I have always used a minimum of 1 sq. ft for any furnace and 1 sq. inch per 1000 BTUs of the furnace input. Thanks.

  2. #2
    Is this a new install?

  3. #3
    In chicago The code is the same 1 sq" per thousand btus
    check your codes and check with your gas company.peoples energy in chicago has a great 86 page book called construction guide for gas usage in chicago.It has all of the codes with pictures as examples.

  4. #4
    Join Date
    Feb 2005
    small island in the Pacific Ocean
    how many btu's is the furnace, is the house R2000 rated, whats the square footage of the enclosure around the furnace are there any more appliances in the same room

    [Edited by phosgene on 12-07-2005 at 02:07 AM]

  5. #5
    Join Date
    Feb 2003
    my Daughter's 1970s vintage gas furn manual states that requirement --
    don't the current manuals?
    harvest rainwater,make SHADE,R75/50/30= roof/wall/floor, use HVAC mastic,caulk all wall seams!

  6. #6
    Join Date
    Oct 2003
    34.8n 102.4w

    You mean

    You're actually suppose it read that thing ??
    They do have nice pictures in them..
    Life goes on long after the thrill of living is gone.

  7. #7
    Join Date
    Aug 2002

    Combustion/Ventilation Air

    I have an older TN code book but I can't find it. I wanted to know what is the MINIMUM size opening to outside air for ANY natural draft gas furnace. Thanks for all the replys.

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