One of the big projects I have slated for this winter is to finally insulate our walls. I’ve been looking into all of the different insulation methods and narrowed it down to two in particular – denim cellulose and spray foam. Both of which are (or at least can be) green, and I can do them myself. Without going into too much detail, the decision was ultimately made based on ease of installation and overall r-value. Cost was also somewhat of a factor initially, but comfort won out over cost in the end and I decided on soy foam insulation. Here are the basic comparisons base on 1200 sq ft of wall space (@ 1 inch deep):

Cellulose

• rvalue = 3.7 @ 1 inch deep


• installation requires at least 2 people and a hopper that can be turned off/on by the person applying the insulation


• total cost for 1000 sq linear ft = $1050 (sorry, can’t find the link at the moment)

Spray foam (soy) Thanks for the correction Jamie!

• rvalue = approx 7-8 @ 1 inch deep


• single person insulation is feasible


• total cost for 1000 sq linear ft = $1370 link to site

So for about $300 more than cellulose insulation we’ll be getting twice the rvalue per square inch. The decision was pretty easy in the end. There is one other “honorable mention” that I should point out. It is still green in the long run and a little closer in price to the cellulose insulation at about $1050 as well, although you will need to keep in mind that the foam I listed above includes shipping and 17 installation tools, while this kit does not (at least not at the time of this writing). I’m hoping to complete this project by mid-January.

There are a few factors to point out first. Last year the thermostat was set three degrees lower than it is this year. Also, the gable fan I installed a few weeks back will have an affect on the results as well. So, this won’t be a direct comparison, but still – the results are noticeable.

Last year, a 95 degree day would have caused the AC to be on somewhere in the neighborhood of 7-8 hours. Yesterday, the AC was on for a total of just under 3 hours – a whole four to five hours less than last year. That’s going to make a noticeable difference. When we replace the windows next winter, and possibly insulate the outside walls (hopefully we’ll be able to) then it should drop that time down to under an hour, I would imagine.