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Insulation Made Easy

There’s value in understanding the R-factor

October 2022

L: Air sealing prevents drafts and air infiltration. R: A contractor installs blown cellulose insulation.

by Miranda Boutelle, Contributing Columnist

Q: What cost-effective improvements will make my home comfortable year-round?

A: It isn’t pretty, but insulation and air sealing typically provide the biggest bangs for your buck when it comes to home energy-efficiency improvements.

When installed together, air sealing and insulation can save you money and make a big difference in comfort and energy use.


Insulation is rated in R-value. The R stands for resistance to heat transfer. The higher your R-value, the slower the heat transfer, or less wasted energy. There are several different types of insulation, including fiberglass batts, blown fiberglass, cellulose and foam. Each has its own R-value listed on the packaging. Generally, the colder the climate, the higher the recommended R-value.


The typical locations for insulation are the attic, walls and floor. If you have a forced-air heating or cooling system, your ductwork should be insulated, too. You want a consistent thermal barrier around your home for maximum efficiency. A bonus to insulation is it can reduce noise from the outside of your home.

Combined with air sealing, attic insulation can prevent ice dams from forming on your roof in colder climates.

Attics can be insulated using batts or blown-in insulation. Recommended R-values range from R-30 to R-60. If you use your attic for storage, you can build a raised platform with room for insulation underneath.

Wall insulation can be installed during construction or a remodel. If your home wasn’t insulated when it was built, a contractor can blow in the insulation. Your home should also be insulated between the floor and crawlspace or unheated basement. If your basement is heated, install insulation in the box sills, the area between the foundation floor of the home’s main level.

Consider insulating the exterior walls in the basement or installing foam insulation on foundation walls. Check your local building code requirements. Recommended R-values for floor insulation range from R-13 to R-30.


Air sealing prevents drafts and air infiltration from outside. It can improve efficiency, comfort and indoor air quality.

Air sealing can be done as a DIY project, but it is challenging to pinpoint and properly seal air leaks. Consider hiring a contractor to complete a blower door test and seal leaks.

Typically, air sealing is done around plumbing and electrical penetrations with spray foam or caulk. If using spray foam around gas appliances, temporarily turn off pilot lights. Spray foam is extremely flammable.

Sheet metal and high-temperature heat-resistant caulk should be used to seal gaps between framing, chimneys and metal flues.


If you are considering a DIY approach, protect yourself when going into spaces with insulation. Wear a properly fitted mask or respirator. Wearing a a protective fabric and gloves also is recommended. Kneepads can come in handy and make the crawling more bearable.

If you are planning a DIY approach for air sealing, do your research about best practices for the proper home ventilation. Before going the DIY route, contact two or three local contractors for a project estimate. Sometimes the contractor can get cheaper bulk pricing on insulation.

Making insulation and air sealing a priority adds comfort, efficiency and savings to your home.

Miranda Boutelle writes on energy-efficiency topics for the National Rural Electric Cooperative Association.