According to Lesley :
I WAS talking about "properly fitted fiberglass". I got a quote of
$1,050 to put recycled denim insulation in the attic rafters. When I
asked him to quote me for the same job using fiberglass, he said it was
so much less efficient that they (their company) didn't use it. . .

So you're saying that Denim *is* more efficient, but "not much more"?
So would you recommend getting a quote from another company--one that
does use fiberglass?

It might be that denim is slightly more efficient than fiberglass.
Cellulose is. But both denim and loose blown cellulose have more
drastic drawbacks (packdown or soakdown or both).

If you're that concerned, look for someone who can do Rockwool and
get a quote.

Rockwool is only a trifle more expensive than fiberglass, is a bit
more efficient than fiberglass, and is better than fiberglass
in most of the other issues with fiberglass.

Better sound control too.

See www.roxul.com for one brand.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.