On Mon, 25 Jun 2007 05:20:27 GMT, "peter" wrote:

The heating ducts come out of the furnace and into crawlspace. There, the
joints are not sealed and leaks hot air.

The longest lasting way to seal these joints is to use hvac sealant,
aluminum tape, or butyl tape?


I've only used the metal tape. Love the stuff, just not when I cut
myself on it. As for mastic, I've seen professional hvac guys use
it, messy stuff, and seems to have to cure before you can start the
system.

tom @ www.FreeCreditCheckGuide.com