- It slows conductive heat
- It stops convective heat and currents in the air of your home
- It reduces radiant heat
- It reduces noise
- It must be perfectly installed. If not you have massive losses in its value.
Here are a few things to look for:
- Lo-VOCs - Most fiberglass is now made with 25% pre & post-consumer recycled glass, and meets California's lo-emitting standards (CA Section 01350)
- Ultra-touch Cotton is >85% post-industrial content. It is made from scraps from the denim factory floor. I have this in my attic.
- Wool insulation is annually renewable. Baaah.
- Cellulose is > 75% recycled content, is formaldehyde free and is great for filling in nooks and crannies in walls. They call it "drill and fill". I also found out I should have used this in my attic to fill all spaces well. Be sure to block around recessed lights and fans though in attics. FIRE DANGER
- Foam is NOT biodegradable, costs a lot of money and it is hard to access wiring and plumbing if repairs are needed. It IS very high efficiency.
- Quality installation can be verified by a HERS rater.
- Check for IAQ (Indoor Air Quality) certification on the product. (Greenguard label, USGBC, Energy Star, Indoor Advantage)
- Check for recycled content labels.
- Is it a locally manufactured?
Architect, LEED-AP, CGBP, Green Point Rater
Find a HERS rater at www.cheers.org or www.cbpca.org, or ask your local building department.