Replies

1. 
   Guest_ | Mar 23, 2000 01:08am | #1

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   You use transite ducts and wherever you need a fitting use a sheetmetal one cast solidly in concrete.

2. 
   Mark_Waldron | Mar 25, 2000 12:03pm | #2

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   I was just reading some posts in the heating and ventilation are of "Breaktime," and one of the writers said he'd never put ductwork under a slab again. His daughter had very bad alergy symptoms, all improved after moving out of the house. He attributes this to the increased amount of dust/mold/bacteria that will accumulate in these below-grade ducts (due to more constant/favorable temps?)
   I don't know how much there is to this, but I do think it is worth thinking about. I'm trying to think of ways to do away with ducts altogether--easy for heat, but only room-by-room AC condensers seem to make it possible to cool without long ducts.

   Mark

3. 
   Guest_ | Mar 25, 2000 12:16pm | #3

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   Mark,

   That might have been me, I don't recall if I posted that here or not, but I had that experience: my yomgest daughter was born in a house partally on slab with some of the ductwork below it, and she was somewhat asthmatic. Since we moved 3 years ago (when she was 6) she hasn't had any asthma symptoms. (The move was from SW PA to NW Ohio - not a significant climate change.)

   I _strongly_ suspect the below grade ducts.

   Bob

1. 
   Guest_ | Mar 25, 2000 01:02pm | #5

   *Mark,Cheaper than AC evaporators in every room (the evaporator is the inside cold coil, the condensor is the outside coil - no biggie), you can use one AC system to chill water which is circulated through the house just like hydronic heating. The cooling units are alittle bigger and have fans built in. One problem is how you'll deal with condensate in every room but it's much easier and less expensive.

4. 
   Greg_Poppin | Mar 25, 2000 01:02pm | #4

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   Does anyone have any suggestions on running a forced-air duct system under a slab?