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How Much Insulation Do I Need in My Attic?

attic insulation

How Much Insulation Do I Need in My Attic? Blog Feature
Amanda Ringler

By: Amanda Ringler on October 5th, 2022

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Have you noticed your attic insulation is all fluffed to one side or has black spots throughout it?

You might also notice ice dams around your home, and your monthly energy bills are through the roof.

These are all signs that it’s probably time for you to update your attic insulation.

Adding insulation in your attic is a great way to improve your home’s comfort and energy efficiency.

Attic insulation can help prevent the air you pay to treat from leaking through the roof. This will keep your home more comfortable and help reduce your monthly energy bills.

Nearly $200 to $400 of the almost $2,000 paid annually by the average American for energy is wasted due to drafts, air leaks, and outdated heating and cooling systems, according to the U.S. Department of Energy.

RetroFoam of Michigan has insulated thousands of attics across Michigan’s Lower Peninsula, so we know how much insulation you need in your attic to meet your goals, no matter what insulation material you choose.

Let’s take a look at how to tell if you need attic insulation, how much to add, and how the state you live in can play a role.

How Do I Know if I Have Enough Insulation in My Attic?

A high energy bill may indicate that it is time to update your attic insulation.

However, you will want to go up into your attic and take a good look around.

Inspect the condition of the insulation you have up there, whether it’s cellulose or fiberglass, and then gauge how much you currently have. If the insulation you have is just level or below your floor joists, then you will need to add more, according to Energy Star.

When you’re evaluating your insulation, and you can’t see any of your floor joists because the insulation is above them, adding more probably wouldn’t be cost-effective.

Cellulose tends to shift and settle, so you might see more than enough insulation in the middle of your attic but hardly any coverage around the perimeter. You will need to ensure it is spread out evenly in the joists to get the coverage you need.

Fiberglass will also settle over time and lose that pink, fluffy cotton candy look we’re all used to seeing. It could look at first like you have enough fiberglass in the attic, but it may not be performing as it should due to moisture and airflow.

How Much Insulation Do I Need in My Attic?

When working with traditional insulation, like cellulose and fiberglass, the theory is that you will need to reach a specific R-Value based on your climate zone.

R-Value is a measure of insulation’s ability to resist heat flow. The higher the R-Value for these traditional insulations, the greater the insulating effectiveness, according to the U.S. Department of Energy.

A general rule of thumb is that the colder your state can get, the more R-Value will be required to insulate your home.

Michigan is in climate zones five through seven. An uninsulated attic would require an R-Value between R49 and R60. If you have an existing 3- to 4-inches of insulation in your attic, you will need between R38 to R49.

You don’t always have to hit that prescribed R-Value.

A product like foam insulation can be used to insulate the attic while having a lower R-Value. Foam insulation performs much better than traditional insulation because it creates an air seal that isn’t possible with fiberglass or cellulose.

The Best Option to Insulate Your Attic

If your current insulation is on the thin side, adding more of the traditional stuff should help.

However, it will not provide the air seal you need to prevent those high bills and other problems.

Some homeowners want a fresh start when it comes to insulating their attics.

If lowering your energy bills and having a healthy home is a priority for your family, the best option for your attic is to remove the old insulation and replace it with spray foam insulation.

The air seal created with spray foam insulation will not only make the home more energy-efficient and comfortable but will also make the home healthy by keeping out pollutants and allergens.

Those traditional insulation materials retain those things, allowing them to circulate throughout the home.

If you want to learn more about the benefits of foam insulation in your attic, check out the Learning Center on our website.

Related Articles

How Thick Does Spray Foam Insulation Need to Be?

What is the Highest R-Value Insulation? (Ratings/Types/Charts)

What is the Best Insulation for an Attic? (Spray Foam vs. Fiberglass vs. Cellulose)

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About Amanda Ringler

Amanda previously has worked as a breaking news and crime reporter, TV news producer, and editor in Flint and Detroit. Throughout her career as a journalist, she has won several awards from The Society of Professional Journalists - Detroit Chapter and the Michigan Press Association. As part of the RetroFoam of Michigan family, Amanda uses her experience as a journalist to write content that will help educate homeowners on the benefits of foam insulation. When Amanda isn’t writing, she’s spending time with her husband and rescued huskies. She also loves knitting, making art, cooking, and hosting dinner and a movie night for friends and family.