Warm air furnace ducting - http://www.hvacmechanic.com/ Forums

Original message

dmtnhwkc

65.38.137.20

"Warm air furnace ducting" , posted Wed 9 Jul 20:26

Can I use aluminum accordian-style duct (the same kind used as venting to retrofit heatilator-style gas fireplaces into old wood fireplaces) as warm-air supply ducting. My ducting will run inside floor joist spaces up against the underside of the floor deck, with insulation underneath (accessed via crawl space). I am building my own house and am trying to avoid the sheetmetal cuts from ridid 6" ducting and I think the mylar stuff is flimsy, prone to offgassing byproducts of plastics.
Does anyone have long-term durability information about the insulated mylar accordian-style air ducts, sometimes called "elephant-trunk". It seems very flimsy to me.

Replies:

answer

68.59.47.234

"Re(1):Warm air furnace ducting" , posted Wed 9 Jul 21:03

I say cut every corner and don't do anything like the pro's, what do they know, and as for "offgasing" Im pretty sure the 10 million miles of flex run in this country has killed quite a few, I know everyone complains of the offgasing.
In review go cheap and easy and do it agan the next year, and then two years later, and then one year after that. Because us duct guys must be doing it the hard way for fun.

Well I am in a mood arn't I this post will be yanked quicker than poor duct.

sorry home owner yea the aluminum stuff will unravel quickly , the flex or elephant is air tight and lasts well in a dry place if it gets wet it will last about 9 years, if installed correctly. Hard pipe will only last as long as the insulation on it and the sealant at the seams.

Be good to your fellow man not nice there is a difference.