Adding Insulation
when Re-Siding (AIRS)

Planning a re-siding project? Scroll down to learn more about our study!

Siding replacement projects are an excellent opportunity to insulate and air-seal a home's walls. Re-siding projects provide rare access to a home's exterior, making window and insulation renovations a handy and cost-effective option. By performing these upgrades during an already scheduled and budgeted re-siding project, homeowners can save thousands of dollars while only adding a few days to the project and avoiding the homeowner disturbance that separate projects would cause. The result is lower utility bills—about 15% on average—and greater comfort. In the Mixed-Humid climate zone this added investment has a positive Net Present Value (NPV) and can pay for itself in as little as 7 years.

Person installing new siding over new insulation on an exterior wall.

Photo by Christian Valoria | Pacific Northwest National Laboratory

Inflation Reduction Act

With new IRA incentives, you can make your home more energy-efficient with the federal government picking up at least some of the tab on everything from stoves to electric vehicles. Learn more: 

Washington Post article: "The government is giving out money for energy upgrades"

PNNL webpage: Home Energy Rebate Tools

U.S. Department of Energy webpage: Home Energy Rebate Programs Guidance

Rewiring America: IRA Savings Calculator


(Specialized versions of this video summarize technical details for contractors and benefits for homeowners.)

Air leaks and poor insulation are common in homes built before 1992—about 68 percent of existing residential buildings lack adequate air sealing and insulation. Poorly insulated walls in residential buildings waste an estimated quadrillion+ Btus per year of energy. Installing R-5 exterior continuous insulation at siding replacement could save more than 25 percent of that total and is considered a top-10 energy upgrade for retrofit investment. Unfortunately, the best solution for this energy and comfort issue requires disturbing exterior siding and trim. Since removing siding can be costly and disruptive for homeowners, there is a unique and underutilized opportunity to perform these energy upgrades during home re-siding projects.

More than one million homeowners replaced approximately 4 billion square feet of exterior siding in 2020. Yet less than 10 percent of these projects capitalized on the opportunity to add 1 inch or more of insulation. Occupants in these homes may be unaware of the improvement opportunities a re-siding project presents.

These energy upgrades may provide:

  • Temperatures closer to thermostat settings
  • Less draft
  • Better humidity management
  • Less noise from the outside
  • Lower utility bills.
Illustration showing outdoor conditions affecting room temperature with poor wall insulation and windows
With poor wall insulation and windows, room temperature tends to follow outdoor conditions and it's hard for the building conditioning system to keep up.
Illustration showing how an efficient building envelope helps regulate interior temperatures
An efficient building envelope limits drafts, moderates surface temperatures, and increases resistance to heat transfer, keeping the interior just right. 

Illustrations by Michael Perkins | Pacific Northwest National Laboratory

Is it Time to Upgrade Your Windows?

Person installing exterior storm window
Photo courtesy of Larson Manufacturing

A re-siding project presents the perfect opportunity to upgrade the windows, too.

Viable window upgrades depend on the condition of the current windows. During the initial stages of re-siding projects, windows may be in worse condition than the homeowner expected. As with adding air sealing and insulation upgrades, the perfect time to upgrade windows is during a re-siding project.

If the home's current windows are in poor condition, replacement is a much simpler process during re-siding than at any other time. Modern double or triple pane offerings from all major manufacturers offer exceptional energy performance that will contribute to lower energy bills and greater comfort.

Reduce heat transfer and prevent summer overheating by choosing ENERGY STAR performance values. For tips on finding and installing ENERGY STAR windows, see: What makes it ENERGY STAR? and Buying and Installing the Right Product.

Window replacement is not the only option, however. If the home’s current windows are in good working order, an exterior storm window with low-e coating (installation example shown on the right) is a cost-effective energy upgrade. These windows can still provide opening options and offer improved thermal comfort and better sound control compared to older windows, at a fraction of the cost of new energy efficient windows.

Low-e storm windows are around $100 to $200 per window and capture a large portion of available energy savings, while new high-efficiency triple pane windows can be over a thousand dollars each, with professional installation. Modern low-e storm windows are attractive and easy for DIY installation.

AIRS Partners

Project partnerships already span several U.S. states—and participation is growing. The campaign welcomes additional partners in any state, including those already represented below. Interested in participating? Contact the AIRS team:

U.S. map with several states shaded in dark green
A Hight on Homes
HUD Innovative Housing Showcase at National Mall in Washington, D.C.
Green River, LLC
Knoxville, Tennessee
Jerusalem Farm
Kansas City, Missouri
River City Housing
Louisville, Kentucky
EDGE Energy
Grasonville, Maryland 
Quarve Contracting
Spring Lake Park, Minnesota
Energy Home Inspection
Chesnee, South Carolina 

Resources and Information

Inclusion in this section does not indicate PNNL endorsement of a company or practice and is solely for the purpose of information.














RETROFIT CHECKLISTS from the office of energy efficiency and renewable energy

Use strategic language from these samples to meet the AIRS Campaign scope of work