Everything You Need To Know About Attic Insulation

If you live in a cold area, it can be expensive to keep your home warm, especially during the winter. As we enter the colder months of the year, you could just accept that your energy bill will increase or turn down the thermostat and rely on winter clothes for indoor use. If you want to cut down on costs while keeping yourself warm, you can get your attic insulated.

Having a properly insulated attic also benefits those who live in warmer climates. During summer, insulating the attic can help stabilize the indoor temperature of your home.

If you’ve decided on getting your attic insulated, you should know that there are different types of insulation you can use and have certain R-values to target. Continue reading to learn more about attic insulation.

What is R-Value?

There are many benefits to getting your attic insulated, but to take advantage of these, you need to make sure that you have proper insulation. The key to making sure that your attic is properly insulated is by getting the right R-value.

According to the Department of Energy, R-value is the rate of the insulating material’s thermal resistance to conductive heat flow. This will depend on the type of insulation, and the density, thickness, aging, moisture accumulation, and temperature of the insulation.

Before getting your attic insulated, you first need to determine your target R-value, which is affected by your geographical location and climate. The Department of Energy has a guide on the recommended R-values for different regions in the United States, which you can check out here.

Different Types of Attic Insulation

Blanket Insulation

This type of insulation is best suited for attics with minimal obstructions and has standard spaces between joints. There should be enough headroom because it can be difficult to install in a low-ceiling attic. It also needs to be carefully trimmed and installed to ensure proper insulation.

R-Value Per Inch

2.9 to 4.3
Fill Counter
3.2 to 3.8
Fill Counter

Fiberglass

Cellulose

3.0 to 3.3
Fill Counter
3.7 to 3.8
Fill Counter

Mineral Wool

Cotton

It uses flexible insulation materials called batts or rolls, which can be made out of fiberglass (2.9 to 4.3 R-value per inch), cellulose (3.2 to 3.8 R-value per inch), mineral wool (3.0 to 3.3 R-value per inch), or cotton (3.7 to 3.8 R-value per inch). They come in varying thicknesses and widths to accommodate the spaces between joints of different homes. Some insulation materials can come with foil or paper facing to act as a vapor retarder or barrier.

Among the different materials, fiberglass is the most popular because it is the most affordable. But some people who are sensitive to fibers opt for a different one because this material may irritate the lungs and skin. They would probably go for cellulose which is fire-resistant and insect-repellent or mineral wool, which is also fire-resistant but more expensive. If you want a material with a higher R-value, cotton is a good choice as it can also block sounds and airflow - but as expected, it will be more expensive.

Loose-Fill Insulation

If your attic has low headroom or plenty of vents, pipes, and cross-beams, then it’s recommended to get loose-fill insulation. It uses insulation fibers that are blown using special equipment or manually placed and spread, which will take more time and effort. This can also be blown over existing insulation in your attic, perfect for those who want to increase their current R-value.

R-Value Per Inch

3.2 to 3.8
Fill Counter
2.2 to 2.7
Fill Counter
3.0 to 3.3
Fill Counter

Cellulose

Fiberglass

Mineral Wool

The available insulation materials for loose-fill are cellulose (3.2 to 3.8 R-value per inch), fiberglass (2.2 to 2.7 R-value per inch), and mineral wool (3.0 to 3.3 R-value per inch). Cellulose is considered the most effective material for loose-fill insulation since it can be used on areas around vents, pipes, and ducts. But the problem with this material is that it can rot and get moldy in moisture-prone areas. That’s why nowadays, newer homes are going for fiberglass or mineral wool, with the latter more popular because it is fire-resistant and since fiberglass may irritate your lungs and make you feel itchy.

Spray Foam Insulation

If you want to seal all crevices, gaps, and space in your attic, it is recommended to use spray foam insulation. There are two types of spray foam insulation: open-cell or ½-pound (3.5 R-value per inch) and closed-cell or 2-pound (6.5 R-value per inch). Both are made with chemicals such as polyurethane but the open-cell is filled with air while the closed-cell is filled with gas. The gas will make the closed-cell foam expand to cover the space. On the other hand, the air in the open-cell foam will give it a sponge-like finish. While both options can act as a sound and air barrier, only closed-cell foams can act as a vapor retarder or barrier.

R-Value Per Inch

3.5
Fill Counter
6.5
Fill Counter

Open-Cell

Closed-Cell

While the two other insulation types are both DIY-able, it is recommended to get a professional for spray foam insulation. This makes it a more expensive option but better suited for those who require a high R-value.

Source: NHSaves

If you are looking for trusted and reliable contractors to insulate your attic, I recommend HomeAdvisor. All the contractors need to be licensed and insured to join this platform. Since they are paying for the opportunity to earn your business, then they are also eager to earn it as well.

LOOKING FOR A CONTRACTOR?

How Much Does It Cost To Insulate An Attic?

The average cost of getting your attic insulated can range from $1,100 to $2,300 or $1.50 to $3.50 per foot, largely depending on the type of insulation you will get. For the labor costs, an installer can land you around $70 per hour. This can increase if you will require an electrician to insulate around cables and electrical boxes, which is an additional $85 per hour.

Blanket Insulation

$0.15 to $0.60 

per square foot

Loose-Fill Insulation

$1

per square foot

Spray Foam Insulation

$1.25 to $1.50 

per square foot

For the different types of insulation, blanket insulation is the least expensive while spray foam insulation is the priciest. Installing batts or rolls can cost around $0.15 to $0.60, depending on the material and thickness. For loose-fill, it costs $1 per square foot for a professional to install. On the other hand, spray foam insulation using open-cells will land you $1.25 per square foot while closed-cell costs around $1.50 per square foot.

Kenneth Wilson
November 15, 2020
Cost Guides

Kenneth Wilson

Retired contractor. Currently residing in Southwest Florida. Now in semi-retirement, I write and manage this blog focused on helping home owners make savvy decisions when it comes to finding contractors and getting their projects done.