Insulating your attic isn’t a thrilling home improvement project, but it’s important. A poorly insulated attic will leak heat, making your home less comfortable in colder months and raising your heating bills. Proper attic insulation helps regulate the temperature in your home, increasing energy efficiency and reducing your utility bills.
Our guide explores the benefits, key steps, materials, and considerations for anyone considering adding insulation to their attic. Read on to learn more.
Benefits of Insulating Your Attic
If you live in a warmer state, you may not experience the benefits of attic insulation quite as starkly as those in colder Northern states. Nonetheless, adding attic insulation is worth it, and anyone should expect the following benefits:
- Cost savings: Using less energy has the secondary benefit of lower monthly utility bills.
- Energy savings: If you reduce your carbon footprint, insulating your attic can prevent heat loss and help your home save energy.
- Extended HVAC lifespan: By reducing the amount of pollutants and other irritants in your home, insulation can prolong the lifespan of HVAC filters and the system itself.
- Improved air quality: Attic insulation can help keep pollutants, dust, and allergens from entering your home through air leaks in your roof.
- More stable temperatures: Attic insulation helps keep air inside the house, helping to stabilize temperatures and making inside air less susceptible to change with the outdoor temperature.
- Quiet: Insulation doesn’t just impact air. It can also help reduce outside noise.
- Reduced risk of ice dams and moisture issues: Thick ridges of ice that build up on the eaves of your house can knock gutters and shingles out of place and seep moisture into your home when they melt. Insulation helps keep them from forming.
How To Check Your Current Attic Insulation Level
If you do have some insulation in your attic but are unsure of its history, it’s worth checking its quality to see if you need more. Doing so may require some climbing and crawling into tight spaces depending on the layout of your attic. Bring a flashlight with you.
Here’s how to check your existing attic insulation level:
- Look at your uncovered attic floor. If the insulation is below the floor joists, you probably need more.
- Measure your layer of insulation with a measuring tape or ruler to determine the depth of the insulation.
- Insulation quality is measured by R-value, which is the resistance of heat transfer through the insulation. To calculate the R-value for most insulation types, every inch of insulation is roughly equal to an R-value of 3 or more. You want an R-value of at least R-38 in Southern climates and R-49 in Northern climates.
Types of Attic Insulation
When properly installed, all types of insulation provide suitable R-values. That said, there’s more than one type of insulation.
Blown-In Cellulose
Cellulose, made of recycled newspaper and cardboard, is an even more eco-friendly attic insulation option. Unlike fiberglass batts, which come in rolls or sheets, cellulose is blown in using a machine to fill gaps fully. It has a higher R-value than fiberglass at R-3.6–R-3.8, meaning you can lay a thinner layer to achieve better insulation.
Cellulose insulation costs $0.60–$2.30 per square foot.*
Blown-in Cellulose Pros
- Fire-retardant
- Higher R-value, meaning you can use less of it
- Most eco-friendly option
Blown-In Cellulose Cons
- Like fiberglass, it can grow mold if it gets wet
- The blown-in method is difficult to do on your own, so you’ll probably need to hire a professional
*Cost data in this article sourced from contractor estimates used by Angi.
Fiberglass Batts
The most common type of attic insulation is fiberglass batts. Resembling pink cotton candy, it’s probably what comes to mind when you think about insulation. Batt insulation is made of tiny fiberglass slivers fused together with a chemical vapor. The standard R-value of fiberglass is R-2.9–R-3.8, meaning you’ll want at least 13 inches of insulation in warmer climates.
Fiberglass insulation costs $0.30–$1.50 per square foot to install.
Fiberglass Insulation Pros
- Is a renewable resource—created from sand that’s turned into glass
- Most do-it-yourself (DIY)-friendly and cost-effective insulation method
- Rarely shrinks or collapses from air changes
- Soundproof
- The vapor barrier is flame-proof, making it fire-retardant
Fiberglass Insulation Cons
- If your home isn’t well-sealed, it can attract rodents
- Moisture can cause structural damage or mold
- Risk of injury during installation
- Risk of missing spots
- Vapor layer is toxic, so you’ll have to wash your hands thoroughly after DIY installation
Spray Foam
There are two types of spray foam insulation—open and closed cell. Spray foam offers significantly higher R-values (R-6–8 for closed cell, R-3.6–4.3 for open cell) than other insulation types and it completely fills space by being blown in in liquid form and hardening to seal all cracks.
Spray foam insulation requires professional insulation and costs $1–$4.50 per square foot to install.
Spray Foam Pros
- Can offer structural support for your home
- High R-values, reaching up to R8
- High-performing and long-lasting
- Highly energy efficient
- Waterproof
Spray Foam Cons
- Expensive and requires professional installation
- If installed incorrectly, it can exacerbate leaking or other moisture issues
- Substances used to create spray foam are toxic and dangerous to the touch—steer clear when the pros are installing it
Structural Insulated Panels
This more expensive and less common attic insulation option involves building insulation directly into the structure of your attic. Structural insulated panels (SIPs) are great for new constructions, but may require a significant renovation to incorporate them into an existing space. Very high R-values of R-8.0 and up may not be enough to justify the $7–12 per square foot expense.
Structural Insulated Panel Pros
- Built directly into your attic
- High R-values, at R-8.0 and above
- High-performing and long-lasting
Structural Insulated Panel Cons
- Expensive and requires professional installation
How Much Attic Insulation Do You Need?
Building codes in most climate zones require insulation of R-49–R-60. How much you need depends on how much insulation you currently have. If you have no insulation, you’ll want to put in new insulation to at least R-60 for maximum efficiency. Otherwise, add enough to get up to R-60.
Understanding Insulation R-Values
Different types of insulation may have higher or lower R-values. That has a direct impact on how much insulation your attic needs. Depending on the material you’re using, what follows are the R-values you should target.
Fiberglass Batts R-Values
- R-value per inch: R-2.9–R-3.8
- Recommended R-value: R-30–R-60
- Thickness needed (inches): 10.34–20.69
Blown-In Cellulose R-Values
- R-value per inch: R-3.6–R-3.8
- Recommended R-value: R-49–R-60
- Thickness needed (inches): 13.61–16.67
Spray Foam R-Values
- R-value per inch: R-3.6–R-4.3 (open cell), R-6–R-8 (closed cell)
- Recommended R-value: R-3.5–R-11.4
- Thickness needed (inches): 13.61–16.67
Attic Insulation Costs
The cost of insulation materials varies depending on the region, accessibility of the space, and contractor.
Cost of Attic Insulation per Square Foot
You can expect to pay the prices below for different types of insulation.
| Insulation type | Cost per Square Foot |
| Blown-in cellulose | $0.60–$2.30 |
| Fiberglass batts | $0.30–$1.50 |
| Spray foam | $1–$4.50 |
| Structural insulated panels | $7–$12 |
Insulation Replacement Cost
It’s unusual that you have to completely replace your attic insulation. Only serious water damage or animal infestation will require removing and replacing all your attic insulation. In these cases, you’ll need to pay for removal as well as replacement.
Removing attic insulation costs between $1 and $2 per square foot, on top of the cost to install the new insulation to complete the replacement.
When insulation is seriously damaged from water or animal infestation, it’s possible that there’s structural or electrical damage to the area as well, which will incur additional costs.
Step-By-Step Guide To Installing Attic Insulation
Basic insulation installation is an easy DIY project. It gets more complicated once you go beyond fiberglass batts to blow-in methods, so you may want to hire a professional. Some tools you’ll need if you’re going to do it yourself include the following:
- Dust mask
- Gloves
- Long-sleeve shirt and pants
- Safety glasses
- Straightedge
- Utility knife
Installing Fiberglass Batts
- Cut to width: To fill narrow stud bays, trim down the batt’s width by laying it in front of the cavity with the inside face inside the stud bay. Then, lay a straight two-by-four in line with the inside face of the neighboring stud, secure it with your knee, and run a utility knife next to the two-by-four to trim the batt.
- Trim the length: To fit the batt to length, tuck the insulation tight inside the cavity with the edges flush with the studs. Let it run long, and then cut it against the wall’s bottom plate to fit correctly.
- Navigate obstacles: To get around wires, halve the batt’s thickness by pulling it apart and frame the wire with one half behind the wire and the other half in front. Cut batts to fit around electrical outlet boxes and plumbing supply pipes.
- Add the vapor barrier: Batts with paper or foil have a vapor barrier, but unfaced batts should be covered with 6-mil plastic or MemBrain by applying a bead of sealant to the top plate and to any studs where the sheets overlap, then tacked every 12–24 inches to the top plate, studs, and bottom plates.
Blown-In Cellulose Installation
Installing blown-in cellulose in an attic is a more involved process. You can do it yourself, but it’s riskier and may be worth hiring a professional. If you want to do it yourself, follow these steps:
Prepare the space:
- Seal all air gaps with caulk or spray foam, and wrap water lines with pipe sleeves.
- Use a tape measure to determine the depth of various spaces around the attic, which will help you determine how much insulation you’ll need.
- Create barriers blocking off areas where you don’t want the insulation to go.
Installing the insulation:
- First, gear up with personal protective equipment (PPE).
- Calculate how much insulation fill you’ll need by reading bag instructions and calculating the square footage of your attic space.
- Connect the hose to a blown-in insulation machine and feed in a half-bag of fill.
- Begin blowing the insulation, starting with the hatches furthest from the door.
- Continue to fill the attic, always pointing away from you and using your gloved hand to direct insulation downward into areas you can’t spray directly into.
DIY Spray Foam Tips
Spray foam can be very toxic, so we recommended that you hire a professional to install spray foam insulation in your attic. You should only venture into doing it if you have experience with spray insulation. If you DIY spray foam insulation, remember these tips:
- Always fully suit up in PPE, protecting your skin and face, and ensure the space has proper ventilation.
- Always read the DIY spray foam kit instructions thoroughly to learn how much to use and how to apply it properly.
- Use closed-cell DIY kits for small areas facing against the exterior.
- Always point the gun away from you, clean the tip after use, and then close it securely.
Tips for Hiring an Attic Insulation Contractor
Some attic insulation projects are manageable, and you can do them yourself, saving some money. However, replacing damaged insulation or installing new insulation can be very involved, toxic projects. If you decide to hire an attic insulation contractor, consider the following tips to get the best price and ensure the job is done right.
Ensure Proper Licensing and Insurance
Part of checking references should include ensuring that a contractor is properly licensed and insured. Each state has different licensing requirements, and you can find a contractor’s status and information on your state government website.
Get Multiple Quotes and Check References
Any time you hire a contractor, you should obtain several quotes to ensure you get the best price. Contractor pricing can range widely, and some will happily explain why they’re more expensive. Don’t just take their word for it. Get at least three quotes and check each contractor’s references and reviews before deciding.
Get a Detailed Contract
Your contract is the legally binding document that ensures a contractor will install the attic insulation to your satisfaction. A contract should include the following:
- A detailed scope of work that accounts for all of the spaces you want insulated
- Labor and additional costs not included in the materials
- Materials used as well as the line item costs of those materials
- Payment schedule if you’re not paying it all upfront
- Warranty guaranteeing the quality of the work for a certain amount of time
Verify Proper Installation
You don’t have to be an expert to verify that the contractor did the attic insulation work correctly. After the contractor completes the job, take some time to check the work, assessing:
- The air sealing of the attic, ensuring there are no gaps that are letting in air
- The coverage area, ensuring there are no insulation gaps
- The density of insulation by measuring the depth and calculating the R-value
How Can I Save Money on Attic Insulation?
Installing attic insulation isn’t the most expensive home improvement project, but it’s always better to save money when you can. There are a number of good ways to save money on attic insulation.
Compare Costs
As mentioned in the previous section, getting multiple quotes is one of the best ways to ensure you save money when hiring a contractor.
Do It Yourself
Doing all or part of the work saves on labor costs. Even removing damaged insulation or putting fiberglass batts into easy-to-access areas of the attic can cut down on a contractor’s billable labor hours.
Financial Incentives
There are many financial incentives that homeowners can take advantage of to lower the cost of attic insulation installation. Rebates, tax credits, and low-income assistance programs are all available depending on your location and situation.
- Assistance for low-to-moderate income families: The Department of Energy’s Weatherization Assistance Program helps households that meet Supplemental Security Income, Aid to Families with Dependent Children, and other income eligibility criteria with a home energy assessment and common home improvements such as sealing air leaks and adding insulation to the attic.
- Rebates: Many local utility companies offer rebates for air sealing and insulation. Search your local utility’s website for rebate programs, or visit the Energy Star Rebate Finder to see what incentives are available in your area.
- Tax credits: The federal government currently offers tax credits for up to 30% of the insulation cost (materials, not labor), not exceeding $1,200. Products that air seal and come with a Manufacturer’s Certification Statement—such as weather stripping, air sealing spray foam, and air sealing caulk—may also apply. This federal tax credit applies through December 31, 2032. Many states also offer energy savings tax credits, so search your state’s website for energy-related credits.
Our Conclusion
Adding insulation to your attic is a relatively inexpensive home improvement project that can pay dividends in energy savings. Whether your living space feels too cold or you’re worried that the insulation may be a bit old, assessing the insulation levels in your attic is a good way to determine if you have sufficient R-value to keep your home’s temperature regulated. If your attic doesn’t have enough insulation, this guide will help you figure out how much more you need and what you can do to replace your attic insulation for the right price.
FAQ About Attic Insulation
Fiberglass batts are generally considered the best insulation type for attics because they’re the cheapest and easiest to install and offer excellent energy efficiency, soundproofing, and air quality protection.
The depth of insulation you need depends on your local climate and the type of material you use. For fiberglass batts, Energy Star recommends at least 13–14 inches of insulation in Southern climates (R-38) or 16–18 inches deep in Northern climates (R-49). For spray foam, you may need 13–16 inches.
Yes, adding insulation to your attic can help regulate the temperature in your home and prevent it from losing heat, lowering the energy needed to heat it. It may cost some money upfront, but you’ll save money in the long run with lower energy bills.
Yes, you can have too much insulation in your attic. At a certain point, an excessive amount of insulation can negatively impact your attic ventilation.
Usually, you won’t need to hire an electrician to install insulation in an attic since there won’t be much wiring. If you have to work around wires or electrical boxes and don’t feel confident cutting fiberglass batts or sealing electrical materials before blowing in insulation, you should hire an electrician to protect your home’s wiring before installing insulation.
Installing fiberglass batts is a potentially toxic, but technically simple job that you can do yourself. We recommend hiring a professional if you’d prefer to use blow-in insulation materials.
You should always air-seal any room before installing insulation to ensure the insulation works properly.
The time it takes to insulate an attic depends on the size of the attic, the accessibility of spaces, and the type of insulation you’re using. In a 1,000-square-foot attic, a professional blow-in insulation installation should take just a few hours. If you’re experienced, you can do it yourself in about the same time. Laying fiberglass batts may take longer, but it shouldn’t take more than a day.
The recommended (and often required by code) R-value for attic insulation is R-49–R-60, while floor insulation should be at least R-25–R-30.
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