I know, stating the obvious right? But I suffered through two freezing winters before I discovered that my New England Victorian built in the 1800′s had no insulation–zero, none, I mean, honestly! Is it even legal to have an uninsulated home in the northeast? Unfortunately, since I was working with an existing home, I could not use the much touted denim insulation which repurposes old denim into a cozy blanket of warmth free of formaldehyde and nasty fiberglass.
I opted for blown-in cellulose insulation (much to the chagrin of my installer who kept pushing the fiberglass. I tried to explain to him that fiberglass is toxic and the fibers when airborne are a potential carcinogen, but it was a lost cause). Cellulose is a green alternative to fiberglass made primarily from recycled newspaper.
The great thing about the cellulose is that all of the work is done from the outside in. Holes are drilled into the side of the house underneath the siding and the insulation is blown in straight from the truck-meaning no mess on the inside and from the outside, you could not even tell where the holes were. The cellulose seeps in and fills the cavities between the joists and is particularly good at seeking out any holes as evidenced by a stream of fluffy cellulose that found it’s way into the house filling up a newly installed pocket door. And it’s true, insulation really does what it’s billed to do–keeps the house warmer in winter, cooler in the summer and dampens outside noise.
I have also heard good things about Icycnene spray foam and a soy based foam insulation.