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We have been listing the things you should do to prepare your home for winter, in order of bang for your buck, as determined by the Rocky Mountain Institute (RMI), which figured out the cost in dollars per ton of carbon saved for each investment you make in time and money. See earlier posts here.
Many houses have attics that are accessible via a hatch in the hall or a cupboard; if you have this, insulating your attic is not that hard, and delivers a good bang for the buck; RMI estimates it will save you 2,142 pounds of CO2 per year, at a cost of $15.56 per ton. We think R-50, or about 16" of glass fiber insulation is a good target. Glass fibre is cheap, relatively easy to install, and noncombustible, so we will look at that first but it is not your only option.
Glass-fiber-insulation maker Owens Corning has set up a Web site at Insulate Your Attic Now that effectively lays out all of the steps needed to do this job, so we won't repeat them here. They make it look like a walk in the park; it isn't, and these are the things you should watch out for.
1. Watch your step: Your ceiling is only 1/2- or 5/8-inch drywall, and the ceiling joists are designed to hold it, not you. Take up a board or plywood to distribute your weight among a number of joists.
2. Watch the vents: There are usually soffit vents that bring outside air into your attic; they are needed in the summer to keep the attic cool. be careful not to bury them.
3. Watch the weather: On a warm sunny day it can get very hot in an attic, dangerously hot. You might also be tempted into shorts and a T-shirt, when you really should
4. Watch what you wear: Glass fibers are itchy. Wear long pants and long sleeve shirt. While Planet Green does not usually recommend disposable stuff, a Tyvek suit is not a bad idea when working with glass fiber.
5. Wear a respirator: A 1994 study found that fiberglass can be "reasonably anticipated to be a human carcinogen;" a 2001 study revised that. Read more at the American Lung Association.
7. Check the hatch: If the box around it is not higher than the fiberglass, then it will fall down every time you open it.
8. Check the lights: Any recessed lights should be approved for attic insulation use; otherwise you will have to build a box out of drywall around them.
9. Take a shower: You don't want any itchy, scratchy fiberglass inside your house when you are finished.
Notes:
- So if there are all these problems with fiberglass, why not use alternatives? Mainly because glass is cheap, effective, fireproof, doesn't rot, and you can do it yourself. To see some of the alternatives visit TreeHugger here.
- Owens Corning insulation, which we link to above, has a Greenguard certificate for being a low emission product with formaldehyde levels less than 0.5 particles per million. However other manufacturers like Johns Manville have no formaldehyde at all.
- If you do not have an accessible attic and have to bring in the pros, it may not be cost effective to add insulation. Don't listen to the salesman; in many cases you have to maintain ventilation spaces to let moisture get out. Hire an independent expert to tell you what you can do first.
Difficulty level: Moderate
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