If you have a dollar, spend it on insulation!

18 04 2008

Appropriately and properly insulating a home or structure may be one of the most substantial green practices you can do to get the most for your money. Paying attention to the building envelope can drastically improve the environmental performance of the systems in terms of heating and cooling the building. The ReGreen guidelines (pg 80 & 81) recommends wall insulating levels of R-30 and higher, and ceiling/roof values of R-50 and higher.  I even heard Barack Obama say that we should insulate our homes so well we could heat them with a candle (of course this brings up a whole host of fresh air and indoor air quality issues – but that’s a whole ‘nother post).

Choosing the right insulation is key for a successful installation, as well as knowing what the insulation is composed of. Many insulations contain formaldehyde, a toxic chemical resulting in poor indoor air quality.

There are a variety of insulation materials that contain high recycled content, are formaldehyde free, and are a sustainable choice for selecting insulation. Cellulose (recycled paper), cotton, fiberglass, foam and mineral wool are some of these options.

Some interesting facts:

Cellulose is composed of about 75% post consumer waste paper, having one of the highest recycled content values among insulation types. It can easily absorb moisture however, so proper sealing and installation techniques are necessary to ensure it will last over time. Check out CIMA for more information.

Cotton insulation has a very low environmental impact, due to the careful attention to processing the material made primarily of blue jeans. Bonded Logic is one company that manufacturers this type of insulation.

Recycled glass makes up 25% or more of all fiberglass. The ReGreen Guidelines states” The insulation industry is now the largest user of recycled glass in the country” (ReGreen guidelines, pg. 103) in reference to the fiberglass material contained in a variety of insulation types. Although a high recycled content, its important to research if the fiberglass contains formaldehydes that can offgas – many companies have begun to use adhesives that contain low VOC’s, approved by Greenguard standards.  Fiberglass also sometimes has a bad rap due to the fibers that can come loose during installation and be inhaled or cause splinters.

We’re considering using foam insulation, Polyisocyanurate – and since we have trouble remembering that word, we’ll refer to it more simply as polyiso for our project. This insulation material is made of a closed cell rigid foam, that comes in a variety of forms (boards, spray, etc). The ReGreen guidelines recommends a foil-faced polyiso for insulating exterior walls (using 4″ thickness creates a R-40 value) and a cellulose spray for the roof. The spray form that we’re considering can be sprayed in the cavities throughout our brownstone renovation. Although the material does not have the highest recycled content, the material comes highly recommended because of its potential energy saving properties, high R-value, as well as increased air sealing and we think its effect on durability far outweighs its lack of recycled content.

This link from the GreenHome Guide is helpful, going into an in-depth explanation of the pros and cons of some insulation types that are available.

Happy insulating!




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