Think of aluminum foil on the underside of your roof. Yes, aluminum radiant barriers are the unsung hero of energy savings. In new homes or remodels you put it on the roof sheathing (underlayment) before the roofing material goes on. There are also ways to retrofit your existing roof. Here are some interesting facts first.
- Install as sheet or laminate to OSB decking (OSB is Oriented Strand Board-now used instead of plywood in many cases)
- Blocks 90%+ of roof deck radiant heat
- Attic should still be ventilated at eaves and ridge
- Check manufacturers warranty. For a while composition shingle companies were afraid of the heat generation back through their product. I think they have eased their concerns lately, but always check.
Case study: Cooling loads in a typical 1500 s.f. Central Florida home. The attic (including heat gains to the duct system) accounts for 22% of the total cooling load. In this house, an attic radiant barrier could save 8-12% on annual air-conditioning costs. (www.fsec.ucf.edu/en/publications/html/FSEC-EN-15/#heat
There needs to be an air space between the roof sheathing and the radiant barrier, there are also spray on barriers. It is possible to retrofit an existing roof by calling your trusted roofing contractor. We use Roofmax in Concord (925) 685-4151 for our roofing needs and I
called. Yes, they install radiant barriers; but any roofing
contractor knows about radiant barriers. www.builditgreen.org
has a green products listing also. I am going to look into this more for my home as well. As my daughter says, "Google it Mom."