Your complete guide to attic insulation

If you’re looking to make your home more comfortable and energy efficient, insulating your attic is one of the most effective home upgrades you can make.

Not only will proper attic insulation make your home more comfortable right now, but it can also increase your home’s value and reduce your carbon footprint.

It’s a wise upgrade all around.

In this guide, we’ll cover attic insulation cost, attic insulation types, and plenty more.

Consider this your one-stop-shop guide to attic insulation, and feel free to skip around to the topics you’re interested in to get your questions answered:

• Why you should upgrade your attic insulation
• When to upgrade attic insulation
• How insulating your attic can increase home value
• What is R-value (and why it matters)
• The different kinds of attics that need insulation
• Attic insulation types
• Attic insulation cost
• How to get your attic insulated at no upfront cost

Spoiler alert: You could get high-performance attic insulation upgrades at no upfront cost if your house qualifies. Discover how.

Why you should upgrade your attic insulation

Here are the three biggest reasons you should upgrade your home’s attic insulation:

1. Attic insulation makes your home more comfortable.
2. Insulating your attic is one of the BEST ways to boost your home’s energy efficiency.
3. Upgrading your attic insulation solves (or prevents) a variety of homeowner issues.

Let’s look at each of these reasons below.

90% of U.S. homes are under insulated

NAIMA.org study

1. Attic insulation makes your home more comfortable 

This is the obvious one. Insulation creates a thermal boundary between your home and the temperature outside, keeping outside temperatures out and inside air in.

When it comes to your house’s attic, creating the best thermal boundary possible is especially important, because your roof is where a lot of the inside heat escapes (in the winter) and outside heat comes in (during the summer).

Insulating and air sealing your attic can go a long way toward keeping air where it’s supposed to be (and it’ll make your home a lot more comfortable in the process).

For a quick visual of how attic insulation and air sealing can help your home stay more comfortable year-round, check out the video below:

2. Insulating your attic is one of the best ways to boost your home’s efficiency 

About 35% of U.S. residential energy use is wasted (1). Yikes!

Homeowners could save up to 45% with insulation and air sealing upgrades, according to a study performed in partnership with NAIMA (North American Insulation Manufacturers Association).

Since so much of the energy you’re buying to heat and cool your house is being wasted, insulating your attic can be a great step toward reducing your monthly energy bills. Discover exactly how insulation saves energy here.

(You might even be able to use the money you save to help pay for the cost of attic insulation.)

Why do we keep talking about air sealing? Learn what air sealing is and why it’s important.

3. Upgrading your attic insulation solves (or prevents) a variety of homeowner issues

If you still aren’t convinced that attic insulation upgrades are an excellent idea, get this— attic insulation can help solve common homeowner problems, including:

• Damaging winter ice dams
• A too-hot upstairs in summer
• Uneven temperatures in your home (even a cold basement!)
• A drafty house
• Indoor air quality issues
• A house that’s too humid

And that’s just naming a few! Proper attic insulation can reduce moisture issues in your home, make your roof last longer, and extend your HVAC system lifespan, and more.

When to upgrade attic insulation

Some types of insulation start to degrade around 10 years of age, which means even if you’ve added some fiberglass batts to your attic in the last decade, it might be time to revisit your attic insulation.

Here are a few signs you may need new attic insulation:

• Increase in the amount of dust in your home
• Noticeably uneven temperatures in areas of your home that used to feel fine
• Cold drafts in the winter
• Stuffy rooms in the summer
• An upstairs that feels like a sauna in July
• You are hearing strange noises (i.e., pests) in your attic or walls
• There’s visible deterioration in your attic insulation (moisture, discoloration, crumbling pieces)
• Your HVAC system can’t keep your house comfortable

Does adding attic insulation increase home value?

Yes, insulating your home’s attic (or upgrading existing insulation) can absolutely increase your house’s value, and—when it comes to your return on your investment—it’s one of the best improvements you can make. 

Homeowners can recoup an average of 116% of the cost of their attic insulation upgrade, according to a 2016 report from Remodeling magazine.

(Compare that to the average financial return on a kitchen upgrade—which is between 56.1% and 52.5%.) 

In short, upgrading your attic insulation is a great investment for long-term home value. Plus, it’ll make your life more comfortable in the meantime.

Read on: Best energy efficient home upgrades and their ROI.

What is R-value? Why is it important to consider when considering attic insulation costs and types?

R-value is a measure of how well a barrier or surface—like a window, wall, or layer of insulation—resists the flow of heat.

Here’s one way to think about it:

When you pour hot water into a paper cup, it can burn your hand. But if you pour hot water into a thermos, you won’t feel anything. That’s because the thermos has a much higher R-value than paper.

When it comes to insulation, R-value is one of the most important things to consider.

The higher the R-value, the more effective the insulation will be at keeping heat inside your house in wintertime or outside your house in summertime—which means your HVAC system won’t have to work as hard throughout the year.

And if your insulation’s R-value is too low for your local climate? A lot of your energy dollars will escape right through the walls and ceiling.

Why is this important? Lots of houses (especially older houses) are under-insulated. Remember, 90% of U.S. homes don’t have the insulation they need (2).

When a house is under insulated, the R-value of the installed insulation isn’t high enough to provide an adequate thermal barrier.

And depending on when your house was built, some areas may have never been insulated at all and might be missing garage insulation, basement insulation, crawl space insulation, or insulation for hidden attics.

All this can make for some chilly winters and muggy summers.

Plenty of homeowners don’t know that their insulation is the problem, though.

In fact, many people assume that their home is uncomfortable because their windows are old.

And, while drafty windows might be part of the problem, they’re usually not the main issue. 

The fact is that even the priciest, most technologically-advanced windows available will only improve your house’s R-value by a few points.

Properly installed insulation, however, can give you a boost in R-value of up to 50 points.

That’s why we often caution our customers against buying new windows unless absolutely necessary.

Yes, new windows can make your home more energy-efficient, but insulation typically makes a far bigger impact on your home’s heating and cooling efficiency.

Get the FREE guide: New windows aren’t the only energy-efficiency myth

Discover the most common efficiency myths in our FREE e-book. Bonus checklists and case studies included.

Get the guide

Insulating the attic: First, how many attics do you have?

Before we jump into attic insulation types and the cost of attic insulation, let’s take a pause and ask a question: How many attics does your home really have?

This question is important because some houses have multiple kinds of attics and some of them are hidden. In fact, many homeowners don’t even know their home may have more than one attic.

And different types of attics require—you guessed it—different types of attic insulation.

Keep in mind, hidden or concealed attics are often uninsulated or under-insulated, which can play a huge role in your home’s climate control efficiency.

And each type of attic requires a unique approach.

Here’s a quick list of the types of attics you might find in your home:

• Standard upstairs attic
• Knee wall attics
• Flat roof (or almost no attic)
• Devil’s peak attics
• Scuttle attics
• Finished and unfinished attics

Check out our full guide to attics to get an in-depth look at the different types.

Regardless of what types of attics you have in the structure of your home, if they aren’t well-insulated and air sealed, you’re going to lose a lot of your energy dollars through the roof.

Attics are prime places for heat exchange. In summer, heat will intrude into your home through the roof or exterior attic walls. And in winter, hot air will escape the same way.

That’s why these spaces should be at the top of your list for insulation upgrades.

Attic insulation types

Let’s talk about one of the major decisions you’ll need to make when insulating your attic: Which type of attic insulation should you use?

Before we go over the various types of insulation, though, an important caveat: Insulating your attic and home can be a complicated task.

It’s crucial that you select the right materials and the right spots to insulate, and—most importantly—the right partners to help with the work.

While it’s important to educate yourself about your insulation project, getting professional help is the best way to be sure that the project actually solves your climate control problems.

At its best, DIY attic insulation runs the risk of not saving you as much on energy as you’d like, and at its worst? It can cause moisture issues in your home.

Check out this lighthearted, vintage Youtube video titled Grandma’s House about insulation supported by EnergyStar.gov for an example of how insufficient insulation upgrades can lead to big challenges.

Okay, hopefully you got a good chuckle (and learned a lot!) from that video. Now, let’s dive into the most popular types of insulation for attics.

Here’s a quick list, and we’ll cover the pros and cons of each below:

• Fiberglass attic insulation
• Spray foam attic insulation
• Cellulose attic insulation
• Less common attic insulation types

Fiberglass attic insulation

When you think about attic insulation, fiberglass insulation is probably what you imagine.

It’s often recognizable by its signature pink and yellow colors, and it’s a great choice if you want to insulate areas like knee walls. 

This type of attic insulation often comes in fiberglass batts, also known as blanket or rolled insulation.

But it’s important to note that blanket or batt insulation also comes in other materials, such as cellulose, mineral wool, or even recycled cloth materials.

(We’ll specifically be talking through fiberglass here.)

While fiberglass batting is a popular DIY attic insulation solution, it’s not always the best long-term solution for every area of your home.

You’ll need to take some extra precautions when using fiberglass, too, because it can be susceptible to moisture and it’s also a favorite snack of raccoons.

Pros of fiberglass insulation:

• It’s easy on the budget and easy to install.
• It’s moisture-resistant when a vapor barrier is also used.
• It requires minimal maintenance.
• It’s fire-resistant.
• It has a lower carbon footprint than some other kinds of insulation.

Cons of fiberglass insulation:

• It can create airborne fibers, which isn’t great for your health or home air quality.
• It has a lower maximum R-value than some other insulation types.
• It’s easy to install it incorrectly, which reduces its overall efficiency.
• It decreases in R-value over time, as it breaks down over time.
• It’s a favorite snack of raccoons (and we assume you don’t want them in your attic).

Estimated R-value per inch of fiberglass insulation:

Fiberglass has an R-value of about 2.9–4.3 per inch.

Spray foam attic insulation

Spray foam attic insulation is one of the newer insulation types out there, and it comes in two varieties: open cell and closed cell.

Open cell is lighter and less dense. It’s better for filling spaces that have lots of little nooks and crannies.

Closed cell is more dense, completely impermeable, and has a higher R-value. But it’s more expensive and can be trickier to install.

Pros of spray foam attic insulation:

• It offers an air-tight seal (especially when paired with attic air sealing).
• It doesn’t require a vapor barrier, unlike fiberglass.
• It’s great in unusual, awkward, and hard-to-insulate spaces.
• It offers a longer insulation lifespan and doesn’t lose R-value over time.

Cons of spray foam attic insulation:

• It has a higher upfront cost than other attic insulation types. (However, depending on where you live, you may be able to get spray foam insulation at no upfront cost.)
• It has a higher carbon footprint than fiberglass insulation.
• It can shrink in locations with severely fluctuating temperatures.

Estimated R-value per inch of spray foam insulation:

Spray foam insulation clocks in at an R-value of approximately 5–6 per inch.

Cellulose attic insulation

Cellulose is a type of blown insulation made from shredded recycled paper, recycled clothing, and even recycled cardboard boxes (all those Amazon boxes need somewhere to go for their second life).

While cellulose doesn’t look pretty, the earth loves it—it has negative lifecycle carbon emissions.

Before installation, the recycled material is treated to make it fire-retardant and pest-repellant.

Then it can be blown in to insulate open areas such as attic floors—or packed in more densely to insulate a contained space.

(Cellulose insulation comes in batts, too, but blown-in insulation is more common.)

Pros of blown-in cellulose attic insulation:

• It’s environmentally friendly and usually made of recycled materials.
• It’s fire-resistant.
• It’s a cost-friendly option for homeowners.
• It has lower health risks than fiberglass.

Cons of blown-in cellulose attic insulation:

• It can absorb moisture easily (that’s why air sealing is crucial!).
• It can create a lot of dust, especially upon install or removal.
• Its R-value reduces over time.
• It requires a vapor barrier.

Estimated R-value per inch for cellulose attic insulation:

Cellulose attic insulation has an R-value of about 3.2–3.8 per inch.

Attic insulation types—alternatives and additions

There are a few alternatives and additions to the most common attic insulation types listed above:

• Structural insulated panels: These are commonly used when building a new home and aren’t used when upgrading attic insulation.
• Reflective insulation: This is a layer of foil that may be added to rigid foam, plastic film, or polyethylene bubble insulation to reflect heat.
• Havlock wool insulation: This type of insulation is made from treated sheep’s wool. It’s non-toxic and is most commonly found in batt form, although Havlock can also be blown-in.
• Rockwool insulation: This material is made from thermal stone wool and is most often seen used in panels, although it can also be utilized in insulation upgrades of older homes.

Attic insulation cost

Installing attic insulation is one of the home upgrades that can significantly increase your comfort while increasing your house’s long-term value. It’s worth it.

Your overall attic insulation costs cost will depend on:

• The insulation material you use
• The size of the attics in your home
• What insulation is already present in the house and it’s condition
• The cost of professional installation in your area
• What additional measures—such as insulation removal or pest control—need to be included in the project
• Financing costs for your home upgrades
• If you get air sealing done at the same time (you really, absolutely should)

The best way to determine out how much attic insulation will cost for your house is to talk to a professional and get a quote.

If your house qualifies, you could get high-performance attic insulation at no upfront cost with Sealed.

That said, here are some ballpark numbers you could expect to pay for materials:

Cost of fiberglass batting insulation

The average cost per square foot for fiberglass insulation is between $0.64–$1.19, though the exact cost will depend on its thickness, R-value, overall quality, and more.

Cost example: 400 square feet of attic space throughout your home, fiberglass batting insulation materials would cost you between $256 and $476.

Keep in mind that this doesn’t include the cost of labor, removing old insulation, or air sealing (which is necessary in most cases).

Here’s why you should air seal your home.

Cost of spray foam attic insulation

The cost of spray foam attic insulation is calculated by what’s called board foot, which is determined not only by square footage, but also depth.

Cost calculations get tricky here, so it’s best to work with a professional for an accurate estimate.

Average board foot prices for spray foam attic insulation are below (this does not include labor cost, removing older attic insulation, or air sealing):

• Open-cell spray foam costs anywhere on average 35 to 55 cents per board foot (3)
• Closed-cell spray foam costs approximately $1.00 – $2.00 per board foot (4)

Cost of blown-in cellulose attic insulation

The average cost for blown-in cellulose attic insulation is between 0.83 and 0.91 for materials.

Again, this doesn’t include labor, air sealing, old insulation removal, or equipment rental to blow in the material. 

Cost example: For 400 square feet of attic space, the cost of materials alone would ring up at between $332 and $364.

Renting a cellulose insulation blower can cost anywhere from $70 to $205 per day (not including a rental deposit).

Installation costs for insulating your attic

If you’ve done a home improvement project before, you already know that the biggest expense in a project isn’t materials, it’s labor.

The cost to insulate your attic—or anywhere in your home—depends on where you live in the country, and the best way to know what you would pay is to get a free home energy assessment and quote for your project.

Just know that analyzing your home for energy-efficiency, planning an insulation strategy, and installing the appropriate insulation are difficult tasks that require professional know-how.

It’s worth the expense to pay someone who knows what they’re doing. (That’s why Sealed only partners with certified home performance contractors for attic insulation and air sealing.)

But there’s good news: You may not have to pay any of these costs upfront.

At Sealed, we came up with a way to pay for powerful home energy upgrades based on energy savings.

Get attic insulation—without breaking the bank

Depending on where you live, you might be able to get professional attic insulation—with complete attic air sealing—at no upfront cost. 

Plus, we take a custom approach to each house, and we’ll guide the project every step of the way.

Your house will get exactly what it needs—and nothing it doesn’t—to feel more comfortable and cut energy waste.

We stand by our work, too. If you don’t save energy, we don’t get paid. Learn more.

Basically, Sealed is the hassle-free and worry-free way to make your home feel amazing.

Want to learn more? Give one of our experts a call today at 917-905-3788.

Or complete our easy 2-minute questionnaire to see if you qualify for high-performance insulation upgrades at no upfront cost.