Results 1 to 8 of 8

Thread: Return Air

  1. #1
    Join Date
    Dec 2007
    Location
    Holladay, UT
    Posts
    565

    Default Return Air

    House I inspected today had a return air grill in main floor dining room. In unfinished basement I saw that this was opened directly into furnace room i.e. no duct connected to main return air. I first thought it was a fresh air vent to outside but on closer inspection saw it was the dining room opening. Why would they have done this and is this allowed?

    Similar Threads:
    F.I.R.E. Services
    Tom Rees / A Closer Look Home Inspection / Salt Lake City, Utah

  2. #2
    Join Date
    Mar 2007
    Location
    Near Philly, Pa.
    Posts
    1,643

    Default Re: Return Air

    Makeup air for the furnace.

    Keep the fire in the fireplace.

  3. #3
    Join Date
    Dec 2007
    Location
    Holladay, UT
    Posts
    565

    Default Re: Return Air

    This is a 3700 square foot house with a completely open basement and furnace room with fresh air vent to outside.

    Tom Rees / A Closer Look Home Inspection / Salt Lake City, Utah

  4. #4
    Join Date
    Mar 2007
    Location
    Near Philly, Pa.
    Posts
    1,643

    Question CAZ

    What size 'furnace room' and what size vent to the outside and is the grille on this vent metal or wood and does it have insect screening?

    Keep the fire in the fireplace.

  5. #5
    Join Date
    Dec 2007
    Location
    Holladay, UT
    Posts
    565

    Default Re: Return Air

    The furnace room is not enclosed making it about 1500 square feet. The whole unfinished basement. I am going back there tomorrow and will take pictures.

    Tom Rees / A Closer Look Home Inspection / Salt Lake City, Utah

  6. #6
    Join Date
    Feb 2008
    Location
    Chicago IL
    Posts
    1,984

    Default Re: Return Air

    Is this an old house? Sounds like a common floor return on old gravity feed systems around here. Maybe they just took the ductwork out at some point. Are the boots/duct oddly oversized and shaped? Remnants of gray/white wrap insulation?

    www.aic-chicago.com
    773/844-4AIC
    "The Code is not a ceiling to reach but a floor to work up from"

  7. #7
    Join Date
    Mar 2007
    Location
    Healdsburg, CA
    Posts
    1,741

    Default Re: Return Air

    2007 CMC & 2006 UMC:
    911.5 Circulating Air. Where a duct furnace is installed so that supply ducts carry air circulated by the furnace to areas outside the space containing the furnace, the return air shall also be handled by a duct(s) sealed to the furnace casing and terminating outside the space containing the furnace. The duct furnace shall be installed on the positive-pressure side of the circulating air blower. [NFPA 54:9.10.5]

    2006 IRC: SECTION M1602 - RETURN AIR
    M1602.1 Return air. Return air shall be taken from inside the dwelling. Dilution of return air with outdoor air shall be permitted.
    M1602.2 Prohibited sources. Outdoor and return air for a forced-air heating or cooling system shall not be taken from the following locations:
    1. Closer than 10 feet (3048 mm) to an appliance vent outlet, a vent opening from a plumbing drainage system or the discharge outlet of an exhaust fan, unless the outlet is 3 feet (914 mm) above the outside air inlet.
    2. Where flammable vapors are present; or where located less than 10 feet (3048 mm) above the surface of any abutting public way or driveway; or where located at grade level by a sidewalk, street, alley or driveway.
    3. A room or space, the volume of which is less than 25 percent of the entire volume served by such system. Where connected by a permanent opening having an area sized in accordance with ACCA Manual D, adjoining rooms or spaces shall be considered as a single room or space for the purpose of determining the volume of such rooms or spaces.
    Exception: The minimum volume requirement shall not apply where the amount of return air taken from a room or space is less than or equal to the amount of supply air delivered to such room or space.
    4. A closet, bathroom, toilet room, kitchen, garage, mechanical room, furnace room or other dwelling unit.
    5. A room or space containing a fuel-burning appliance where such room or space serves as the sole source of return air.
    Exceptions:
    1. The fuel-burning appliance is a direct-vent appliance or an appliance not requiring a vent in accordance with Section M1801.1 or Chapter 24.
    2. The room or space complies with the following requirements:
    2.1. The return air shall be taken from a room or space having a volume exceeding 1 cubic foot for each 10 Btu/h (9.6 L/W) of combined input rating of all fuel-burning appliances therein.
    2.2. The volume of supply air discharged back into the same space shall be approximately equal to the volume of return air taken from the space.
    2.3. Return-air inlets shall not be located within 10 feet (3048 mm) of any appliance firebox or draft hood in the same room or space.
    3. Rooms or spaces containing solid-fuel burning appliances, provided that return-air inlets are located not less than 10 feet (3048 mm) from the firebox of such appliances.

    Jerry McCarthy
    Building Code/ Construction Consultant

  8. #8
    Join Date
    Dec 2007
    Location
    Holladay, UT
    Posts
    565

    Default Re: Return Air

    Thanks Jerry.

    Tom Rees / A Closer Look Home Inspection / Salt Lake City, Utah

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •