Adding more duct insualtion for attic system - Relectix ?

[rkpatt]

The HVAC tech old me that the existing insulation on my attic was impoperly installed - overstreched and compressed 30 years ago ) and is contribution to the 12 degree Delta-T in long duct runs on a hot day . He suggested that I could add more insulation of the existing fiberglass myself using the Reflectix ( or similar ) foil double faced bubble wrap type insulation and foil tape. He told me that I can purchase the 4 ft wide stuff at HD in 25 ft rolls at HD or longer rolls at a supply house nearby under his account. Before I get started , I just want to make sure that the Reflectix bubble type material will be as good or close in R-value as foil backed fiberglass . What do you guys think ? - Thanks

[Steve Wiggins]

Yeah when new the reflectiveness is great but after a layer of dust settles on it ...not so good.

Air currents through insulation reduce R-value. So you will get the most benefit by having the old insulation and duct tape taken off (be sure it is not asbestos) mastic applied to seal the air leaks at each joint and horizontal seams. This is NOT a do-it-yourself job. In fact what you were about to do was going to be a great big waste of time.

[rkpatt]

Thanks for your reply Steve . I sort of suspected that there was catch with that the reflective bubble insulation and maybe it is not as good as the blanket type . Actually I could do the sealing and reinsulation. It would be slow going and itchy . I would probaly start with the long runs first .

[Edited by rkpatt on 07-06-2006 at 03:33 PM]