Weatherstrip, Insulation, Energy Star and R Value

Insulation is what helps keep your home warm in the winter and cool in the summer. It also gives your heating and air conditioning units a break during these months. However, knowing what kind of insulation you need, where you need it, and what an R-value is can be confusing.

By properly insulating your home you can create a more comfortable, consistent indoor climate while significantly improving your home’s energy efficiency.

This guide will help you learn about the different types of insulation used in residential construction, and give you the knowledge and confidence necessary to make the right purchase decision to meet your home needs.

What is R Value?

The most important number is R Value.  R-value is the measure of a material’s ability to resist heat conduction. The greater the material’s R-value, the better it performs as an insulator. All values assigned to insulation are based on specific thicknesses and are usually noted on the packaging.

Compressing or otherwise reducing the thickness of insulation reduces its ability to resist conduction. Find your region on the map and use the chart to determine the r-value you need.

How to Select Insulation: If you’ve ever walked through the aisle at your local Lowes store, you’ve seen the amazing array of products available for our home’s today. Each type has it’s strengths and weaknesses, but how do you know what kind to buy?

1. Determine where additional insulation is needed.
2. Determine what R-value you need for maximum insulation efficiency.
3. Determine the type of insulation you need.
4. Calculate the quantity of insulation you should buy

Check these areas for the opportunity to add insulation

1.  Attic – Slide a yardstick or tape measure into the existing insulation. If it is not up to 19 inches deep, add more.

2. Basement – check rim joists and basement walls.

3. Crawlspaces – check between floor joists if vented, and check perimeter walls if unvented.

4. Exterior walls and floors – turn off the electricity first, then check by removing an electrical outlet cover.

5. Garage – check garage walls and ceilings that are adjacent to conditioned spaces in the house.

Click on the map to find your recommended levels of insulation from

Types of Insulation

Insulation is made from a variety of materials, and it usually comes in four types: rolls and batts, loose-fill and rigid foam.

Rolls and Batts: Rolls and batts — or blankets — are flexible products made from mineral fibers, such as fiberglass and rock wool. They are available in widths suited to standard spacing of wall studs and attic or floor joists: 2 inch x 4 inch walls can hold R-13 or R-15 batts; 2 inch x 6 inch walls can use R-19 or R-21 products.

Loose-Fill Insulation.  Loose-fill is usually made of fiberglass, rock wool, or cellulose in the form of loose fibers or fiber pellets. It should be blown into spaces using special pneumatic equipment.

The blown-in material conforms readily to odd-sized building cavities and attics with wires, ducts, and pipes, making it well suited for places where it is difficult to effectively install other types of insulation.

Rigid Foam Insulation: Rigid foam is typically more expensive than rolls and batts or loose-fill insulation, but it is very effective in exterior wall sheathing, interior sheathing for basement walls, and special applications such as attic hatches. Foam R-values range from R-4 to R-6.5 per inch of thickness, which is up to 2 times greater than most other insulating materials of the same thickness.

One of the most cost-effective ways to make your home more comfortable year-round is to add insulation to your attic, including the attic trap or access door, which is relatively easy.  To find out if you have enough attic insulation, measure the thickness of the insulation.

If it is less than R-30 (11 inches of fiberglass or rock wool or 8 inches of cellulose), you could probably benefit by adding more.

If your attic has enough insulation and proper air sealing, and your home still feels drafty and cold in the winter or too warm in the summer, chances are you need to add insulation to the exterior walls.

This is more expensive and usually requires a contractor, but it may be worth the cost—especially if you live in a very cold climate. If you replace the exterior siding on your home, consider adding insulation at the same time.


You can use weatherstripping in your home to seal air leaks around doors or windows.  Choose a type of weatherstripping that will withstand the friction, weather, temperature changes, and wear and tear associated with its location.

For example, when applied to a door bottom or threshold, weatherstripping could drag on carpet or erode as a result of foot traffic. Weatherstripping in a window sash must accommodate the sliding of panes — up and down, sideways, or out. The weatherstripping you choose should seal well when the door or window is closed but allow it to open freely.

Choose a product for each specific location. Felt and open-cell foams tend to be inexpensive, susceptible to weather, visible, and inefficient at blocking airflow. However, the ease of applying these materials may make them valuable in low-traffic areas. Vinyl, which is slightly more expensive, holds up well and resists moisture.

Check local building codes and as always, it helps to have the right tools for the job. The basic tools you need are: a tape measure, utility knife, straight edge, lightweight stapler, or hammer tacker to secure insulation in place, and a putty knife.

Working with insulation can cause itching and skin irritation, so make sure you take proper safety precautions. Wear long sleeves and pants, work gloves, safety glasses, and a dust mask or respirator to avoid irritating your skin or breathing in harmful substances. Vacuum your clothing immediately after to help reduce the chances of skin irritation.

It’s also a great idea to bring a portable light, especially when working in attics and crawlspaces, plywood to stand on, a rake for insulation adjustment, and insulation supports. All these tools and materials will come in handy during your project.

By Victoria Stone