With their many years of experience, Interior Weatherization has demonstrated consistently that it is fairly easy to invest up to $4,000 or $5,000 in existing shelters and save 35 percent in energy costs and use.
Insulating exposed concrete walls is one of the very important and easy energy saving retrofits for any weatherization. Exposed concrete walls can be insulated below ground and to the first floor. Often this can save 30 to 40 percent of the heat loss in these uninsulated basements and crawlspaces.
Often a simple examination of the heating system, checking everything from the tank and the boiler to the chimney, the combustion air, placement of a wood stove, duct location and a check of the distribution system, and upgrading these elements or repairing any malfunctioning ones can often lead to 10 to 20 percent savings in energy.
One of the more daunting and discouraging elements is the continuous confrontation with poor design and ill-adapted materials and building elements for our climate. For instance, bay windows in mobile homes, jalousie single-pane windows in houses, poor chimney/ceiling connections, which leak and can cause indoor air quality problems and dangerous gas backdrafting. And then there are the electric and water usage fixes, lighting, refrigerators, water heater problems, and fixing plumbing leaks: all are crucial repairs.
A consistent message is how effective weatherization can be in lowering energy costs and energy cost vulnerabilities in existing housing. Typically with an investment of several thousand dollars, a 35 percent savings can be achieved.
Using the Alaska AK Warm energy rating software, a simple payback for retrofit items can be calculated. The process that goes into prioritizing the opportunity to retrofit considers the cost and annual savings based on the years that it takes to earn the initial investment back. If the weatherization team is confronted with two upgrades that have similar paybacks, the priority goes to the upgrade with the longest expected lifetime in the building. The return on investment is calculated by dividing the annual savings by the total cost. That equals the percentage annual return on investment.
Example House #1
Estimated heating cost per year $7,092 (2,200 gal of heating oil + electric)
Uninsulated concrete block foundation-unfinished basement
2?4 16" oc, R-11 walls
Mix of single-, double- and triple-pane windows
R-11 batt with 3" cellulose in attic
1915 cfm50 (air change rate)
74% combustion efficiency of oil furnace
The estimated heating cost of Example Home #1 was $7,000 a year. It had an uninsulated concrete block foundation. For House #1, putting 4" of foam 2 feet below grade with a 2" wing 2 feet out was estimated to save $2,000 or 28 percent of the fuel costs. The cost to complete it $3,500, so a simple payback was 1¾ years and the return on that investment is 57 percent. This certainly is a signal to anyone out there who has an under-insulated basement. It would really pay to do a better job insulating that basement.
James Lee is the director of Interior Weatherization, a low-income weatherization nonprofit, working to help achieve retrofit of low-income homes through support from the federal government and the Alaska Housing Finance Corporation. James Lee's presentation is available at the CCHRC Web site, www.cchrc.org