The folks at GreenovationTV and Old House Web are working on a net-zero energy renovation of a 100-year-old home.  Through the process, they’re posting helpful videos, including this one on insulating uninsulated spaces.  This kind of information is on the money for anyone living in an existing home, especially if you’re like me and you own an old house from 1958!

According to the Department of Energy, having the right insulation system is “one of the fastest and most cost-effective ways to use a whole-house approach to reduce energy waste and make the most of your energy dollars.

In the above video, for example, the house has no attic insulation (other than a layer of old newspapers), no wall insulation, and insufficient basement insulation.  To rectify the insulation situation, a team seals all the air leaks, adds blown cellulose to the attic and wall cavities, and applies spray foam to leaky areas in the basement.

You may be wondering how to add insulation to uninsulated walls.  Here, the contractor removes a single piece of siding and fills each cavity with the cellulose.  Certainly, if you’re replacing old siding, it would be a good idea to add insulation at the same time.

If you’re not sure how much insulation is necessary, check out this Zip Code Insulation Calculator provided by Oak Ridge National Laboratory.  Also, keep in mind that you may be entitled to various federal, state, and local incentives for adding insulation to your home.

[+] Watch more Going Green in an Old Home videos.