Is It Worth It to Add Insulation?
Last updated March 2015
You’ll find lots of online calculators that estimate projected savings and the payback period based on information you provide about your home, current energy prices, and other variables. But these projections often vary dramatically from actual experience. Particularly avoid calculators or estimates provided by trade organizations.
One useful calculator comes from the Lawrence Berkeley National Laboratory (LBL). The Home Energy Saver audit tool provides a full assessment of your current energy use, possible cost-savings—including savings from adding insulation—and payback time for efficiency improvements. It also calculates energy and carbon emissions saved.
Actual energy savings from a given improvement vary according to the specifics of your home. If you use the LBL tool, or any other audit tool, the more information you put in, and the more specific it is, the more accurate the estimate of savings will be.
The table below shows the recommendations and cost-saving projections Home Energy Saver made for a hypothetical 1,800-square-foot two-story home in the Puget Sound area.
Estimated Payback from Reducing
|Current||Upgrade||Projected one-year savings|
|Uninsulated, unfinished attic||Insulate to R-38||$555|
|Unfinished attic with R-11 insulation||Add R-27 of insulation to bring total to R-38||$161|
|Unfinished attic with R-11 insulation||Add R-27 of insulation to bring total to R-38 and install weatherstripping||$389|
A caveat: These projections are rough guidelines based on average energy prices and other assumptions. But the projections clearly show that if you don’t have any attic insulation now, adding to the recommended level and sealing big leaks produces substantial savings that fairly quickly recoup the costs of the improvements.
You may be able to take advantage of rebates and incentives offered by your utility company to help pay for insulation improvements and other work. Puget Sound Energy (PSE) offers various rebates to homeowners who make energy-saving improvements. For example, at the time of this writing it offered a 50 percent rebate for attic insulation work, with a maximum rebate of $600; and a 50 percent rebate for air-sealing work, with a maximum rebate of $350.