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  1. #1
    Join Date
    Feb 2007
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    ductless forced air / crawl space plenum

    Hi... We recently bought our house and discovered that the heating system is a forced air system, but does not have any ducts from the furnace to the floor vents. The heat apparently fills the crawl space and then the warm air gets pushed up the vent holes, as well as up "ducts" made out of the dry wall and studs in the walls.

    Is this safe? is this normal? we are concerned about breathing the dirt, dust, bugs and PINK INSULATION that is sitting just inside the floor vents. it is apparent that the crawl space does not have a vent out system, as the air blows up the vents pretty good, with no other place to go.

    We have thin mini filters under the vents, but that can't be enough...? the bottom of the crawl space is just medium sized rocks, I dont believe there is a vapor barrier under it either...

    Our inspector seemed to have completely missed this fact about our heating system and didn't alert us to how it was made. We are considering taking him to court, because we wouldn't have bought the house like this, or would have asked the seller to fix it.

    I guess I am asking is this system normal? should our inspector have noticed this?? can we fix it? and to what extent are we looking at on this project? I am thinking we just need to hook up a ducting system to all the vents.

    the furnace is electric, and its just sitting in a closet, it's not even attached or screwed down and blows into the crawl space through a hole in the bottom of the closet.

    any input or suggestions are most welcomed!

  2. #2
    Join Date
    Apr 2005
    new jersey
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    You need duct work installed. call a hvac co.

  3. #3
    Join Date
    Feb 2003
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    many commercial sites

    use the ceiling plenum above a dropped ceiling as an open return. But you filter the air on the way back to the air handler. Does the closet have access to an attic to run supply ductwork. Maybe the crawl plenum can be converted into a return. Maybe electric baseboard would be a better solution or a heatpump that could provide cooling in the summer.

  4. #4
    Join Date
    Feb 2003
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    this is a cheap way for an install --
    else $$$

    immediately -- put down 6mil thick pvc -- if there is not one under the rocks = easy to check.
    be sure to leave 4- 6inches masonry exposed to look for termites, etc on sidewalls -- overlap pvc 1ft & seal with duct tape

    foam or caulk the joint between the wood & masonry
    insulate crawl walls -- leaving exposure near bottom --
    insulate the rim board above the crawl walls
    2inch thick Styrofoam is good & can be glued

    maybe foam around all pipe penetrations! maybe, because these may have no insulation between pipe & exterior wall = possible freezing.

    is there a filter on the top of the furn?
    w/o one, the blower may be quite dirty!

    where is the pink insulation installed?

    w/o ductwork the amount of air to ea room is probably not controlled -- so, the room next to the furn will be the hottest. -- unless the supply holes are of different sizes --

    read carefully the disclaimer of the inspector!
    harvest rainwater,make SHADE,R75/50/30= roof/wall/floor, use HVAC mastic,caulk all wall seams!

  5. #5
    Join Date
    Aug 2006
    Seattle Area
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    I have to agree with Coolmen... You should have ductwork.

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