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Adding sufficient attic insulation is an excellent way to protect your home from temperature extremes and moisture damage while reducing heating and cooling costs. Insulation acts as a barrier to prevent the transfer of heat flow from the inside to the outside of the house in winter or from the outside to the inside in summer.
After reviewing several types of attic insulation, including the most sought-after products, our top pick is the Owens Corning R-38 Faced Fiberglass Insulation. Made of stiff fiberglass batts, this insulation is easy to cut and install and won’t slip out of place. It also offers a Kraft paper-faced side to mitigate moisture issues.
We also spoke to a veteran roofer and contractor for an expert opinion on insulation types for attics, R-values, and when to DIY versus when to call in a professional. Read on for key tips and a curated list of some of the best attic insulation products on the market.
- BEST OVERALL: Owens Corning R-38 Faced Fiberglass Insulation
↓ Jump to Review - BEST BANG FOR THE BUCK: Frost King CF1 “No Itch” Natural Cotton Insulation
↓ Jump to Review - BEST BLANKET: Owens Corning R-30 Unfaced Fiberglass Insulation
↓ Jump to Review - BEST BLOWN-IN: Greenfiber 25 lbs. Cellulose Blown-In Insulation
↓ Jump to Review - BEST RADIANT FOIL: US Energy Products Double Bubble Foil Insulation
↓ Jump to Review - BEST FOAM BOARD: Owens Corning Pink Insulation FOAMULAR 250 Board
↓ Jump to Review
Before You Buy Attic Insulation
In most circumstances, it makes sense to add attic insulation. However, in a few situations, installing insulation can cause serious problems, such as in older homes that were built with large gaps between the walls to account for the moisture that naturally leaks into homes. The gaps allow the moisture to dry without causing damage to the structure, but if these spaces are filled with insulation, it can absorb the moisture and lead to mold and rotted wood.
If you have an old or wood-shingled roof and you attempt to install insulation on the ceiling of your attic, a similar situation could occur. These older roofing materials were made to get wet, breathe, and dry, but with insulation blocking the wood, the moisture will only accumulate.
According to Michael Casolaro, President & Owner of MCAS Roofing & Contracting, Inc. in Croton-on-Hudson, New York, you should avoid adding insulation to attics with existing ventilation or moisture issues. “If your attic has existing moisture problems, mold, poor ventilation, or exposed wires, homeowners should avoid installing insulation before first fixing these issues. Adding insulation to an attic in any of these conditions can make your problems worse,” he says.
Also, avoid using insulation anywhere near knob and tube wiring, which is an outdated electrical system that’s a major fire hazard and should be replaced as soon as possible.
Attic Insulation Comparison Chart
| Type | R-Value | Material | |
| Owens Corning R-38 Faced Fiberglass Insulation | Blanket | R-38 | Fiberglass |
| Frost King CF1 “No Itch” Natural Cotton Insulation | Blanket | R-4 | Cotton |
| Owens Corning R-30 Unfaced Fiberglass Insulation | Blanket | R-30 | Fiberglass |
| Greenfiber 25 lbs. Cellulose Blown-In Insulation | Blown-in or spray foam | R-19 to R-60 | Cellulose |
| US Energy Products Double Bubble Foil Insulation | Radiant foil | Not specified | Aluminum polyester and polyethylene |
| Owens Corning Pink Insulation FOAMULAR 250 Board | Foam board | R-10 | Extruded polystyrene |
Our Top Picks
The top-rated products below were chosen for their quality, price, and customer satisfaction to help you find the best attic insulation to protect your home from high- and low-temperature extremes.
Best Overall
Owens Corning R-38 Faced Fiberglass Insulation
What We Like
- GreenGuard Certified for low chemical emissions
- Features a Kraft paper vapor retarder
- DIY-friendly; easy to cut and install
- Can be installed on top of existing insulation
What We Don’t Like
- Must be covered with a 15-minute thermal barrier
Specs
- Type: Blanket
- R-Value: R-38
- Material: Fiberglass
Install this insulation from Owens Corning in an uninsulated attic or add it as a second layer to increase the R-value potential of a home and cut heating and cooling costs. It features a Kraft paper barrier to help prevent moisture issues and is GreenGuard-certified for low chemical emissions into indoor air.
Each package includes eight pieces of fiberglass attic insulation, and each piece measures 48 inches by 16 inches. Using all eight pieces without cutting them covers a 42.67-square-foot space with 12.5-inch thick insulation. This blanket-style attic insulation is easy to cut and install, and the thick insulating material also helps reduce noise and vibration in your home.
Get the Owens Corning R-38 attic insulation at The Home Depot or Lowes.
Best Bang for the Buck
Frost King CF1 "No Itch" Natural Cotton Insulation
What We Like
- Suitable for attic floors, ceilings, and walls
- Doesn’t require gloves or safety glasses when cutting
- Works around pipes, ducts, windows, and doors
- Resistant to mold, mildew, and fire
What We Don’t Like
- May not provide ample thermal insulation
Specs
- Type: Blanket
- R-Value: R-4
- Material: Cotton
Affordable and effective, this natural cotton attic insulation by Frost King is 1 inch thick and measures 16 inches by 48 inches. Use one or more pieces on attic walls, floors, and as attic ceiling insulation, or cut or rip up smaller pieces of insulation to fill in gaps around pipes, ducts, windows, and doors.
While this isn’t waterproof insulation, it’s made with cotton denim that’s resistant to mold and mildew. This is an all-natural alternative to woven fiberglass. Moreover, natural cotton denim is safe and easy to install with just your hands and a utility knife.
Get the Frost King attic insulation at Amazon, Ace Hardware, The Home Depot, and Walmart.
Best Blanket
Owens Corning R-30 Unfaced Fiberglass Insulation
What We Like
- Made with 65 percent recycled content
- Easy to cut and position
- Helps regulate heat in every season
- Provides noise-reducing benefits
What We Don’t Like
- May not provide ample thermal insulation
Specs
- Type: Blanket
- R-Value: R-30
- Material: Fiberglass
This blanket insulation from Owens Corning is easy to cut, position, and install in almost any space. The woven fiberglass insulation is made with 65 percent recycled content and feels as soft as cotton.
This blanket insulation for a roof with attic space comes in 9-inch-thick insulation rolls. It boasts an R-value of 30, keeping your home warm in colder months and cooler in the warmer months. It also aids in reducing the transmission of noise.
Get the Owens Corning R-30 attic insulation at The Home Depot, Lowes, or Ace Hardware.
Best Blown-in
Greenfiber 25 lbs. Cellulose Blown-In Insulation
What We Like
- 25 percent reduction in heating and cooling costs
- Made with 85 percent recycled material
- Reduces noise by 60 percent
- Reduces fire hazards
What We Don’t Like
- Some users report unpleasant smell
Specs
- Type: Blown-in or spray foam
- R-Value: R-19 to R-60
- Material: Cellulose
With versatile application options and an R-value of R-19, the Greenfiber Cellulose Blown-In insulation is a viable option for attics, sidewalls, and ceilings. Whether you spray it on or opt for blow-in application, this insulation is easy to apply over existing insulation or alone and reduces your heating and cooling costs by up to 25 percent.
This insulation can cover 48 square feet of attic space and is suitable for all climates. It also reduces noise in your home by 60 percent, is made with 85 percent recycled material, and uses low-energy manufacturing. Finally, it has ample fire resistance and is carbon-locked, which makes it long-lasting.
Get the Greenfiber attic insulation at The Home Depot or Lowe’s.
Best Radiant Foil
US Energy Products Double Bubble Foil Insulation
What We Like
- Reflects up to 97 percent of heat
- Suitable for high-heat regions
- Light weight for easy cutting and installation
What We Don’t Like
- Needs used with foam board or blanket insulation
Specs
- Type: Radiant foil
- R-Value: Not specified
- Material: Aluminum polyester and polyethylene
This radiant foil attic insulation by US Energy Products is a solid option when paired with another insulating material like foam board or blanket insulation because radiant foil can reflect up to 97 percent of radiant heat. The secondary insulator resists the flow of the residual heat. This insulation is easy to cut with a utility knife or scissors and simple to install with staples, nails, or an adhesive.
The insulation acts as a sandwich, with two layers of reflective metalized aluminum polyester film on the outside and two layers of polyethylene air bubbles on the inside. The air bubbles reduce the flow of heat, while the foil reflects the radiant heat. This construction keeps homes cool in warmer climates and warm in colder weather.
Get the US Energy insulation on Amazon.
Best Foam Board
Owens Corning Pink Insulation FOAMULAR 250 Board
What We Like
- Suitable for attics, cavity wall insulation, and more
- Easy to install; can be cut if necessary
- Keeps moisture out
- Maintains R-value in extreme temperatures
What We Don’t Like
- Some users report awkward sizing
Specs
- Type: Foam board
- R-Value: R-10
- Material: Extruded polystyrene
Foam board insulation is rigid and lightweight, making it easy to carry and install on floors, walls, ceilings, and around windows. Use a warm utility knife to slice through this foam board from Owens Corning with a high degree of precision. This method allows users to form the insulation to the exact size requirements or even to cut rounded shapes in the foam board so heat isn’t lost around pipes or other obstructions.
This insulation has low water absorption potential and is ideal for creating a vapor barrier in narrow gaps around windows and doors where significant amounts of heat can be lost from a home in the winter months.
Get the Owens Corning attic insulation on The Home Depot.
How We Chose the Best Attic Insulations
We researched the most sought-after attic insulations in their respective categories and discovered that the best options are determined by their type, R-value, materials, ease of application, and other special features included by select brands.
While assembling our list of top picks, we made sure to include diverse options, including blanket, spray/blow-in, radiant foil, and foam board insulation with R-values ranging from R-1.3 to R-40 for any required heat resistance. These insulation options are made with fiberglass, cotton, cellulose, polyester, polyethylene, and polystyrene, all of which are easy to install and suitable for cutting or adjusting as needed.
Our top picks also offer mold-, mildew-, and fire-resistance and the added benefit of noise reduction. Plus, many of the above options are made with recycled or pre-consumed materials and are eco-friendly.
Types of Attic Insulation
Several different types of attic insulation are available, including blanket, spray foam, radiant foil, and foam boards, each with benefits and shortcomings.
According to Casolaro, the three best types of attic insulation include spray foam, fiberglass batts, and blown-in insulation. “Spray foam does the best job of insulating your attic, but it’s the most expensive,” he says “Fiberglass batts are affordable, but it’s more likely that air will leak through gaps. Most often, I’ll recommend blown-in insulation, which balances effectiveness with cost.”
Read below for a more detailed look at the pros and cons of each type of attic insulation so you can decide which is best for your unique circumstances.
Blanket Insulation
Blanket insulation is one of the most common types of insulation for walls and attic floors; however, don’t use it in open spaces because the fiberglass particles can affect the air quality in your home. Cut the thick pieces of insulation to fit tightly between the gaps in wooden frames or around pipes, wires, and other obstacles.
While this insulation is also one of the most inexpensive and easiest types to install, it isn’t as effective as spray foam insulation. When installing blanket insulation, wear a breathing mask and protective gloves to avoid irritating your lungs and skin.
Spray Foam
Spray foam insulation is the primary type of attic insulation. Pair it with blanket insulation to better insulate edges and corners, and use it to seal gaps in existing walls. Spray foam attic insulation costs more than other types and can be a hassle to remove. However, it’s the most effective option for insulating your home against the transmission of hot and cold air.
The spray foam is made of liquid polyurethane, which, when sprayed into the cavity of your wall or attic, expands and hardens into a solid foam. If you haven’t used spray foam insulation before, consider hiring a professional to install it to ensure your home is adequately protected.
Blow-In
Blown-in insulation refers to blowing or spraying insulation products into wall cavities, attics, and floors. Methods vary depending on the form of insulation selected. Two of the most common types of blow-in insulation are fiberglass, rock wool, and cellulose, which are applied in an attic space with a blowing machine for easy, even distribution.
Conveniently, most blown-in options can be applied over existing insulation and fill between existing wall studs and ceiling joists for increased insulation.
Radiant Foil
Because it’s designed primarily to reflect heat away from your home, radiant foil insulation is more common in warmer climates. It works through its reflective foil barrier, which is attached to kraft paper or polyethylene bubbles. The bubbles help prevent the transfer of heat through the barrier because they provide a pocket of air, which reduces the rate at which heat can move through the substance.
While standard insulation reduces the flow of heat, radiant foil reflects it. Because of this difference, radiant foil cannot be measured using the same factors attributed to blanket, spray, or foam board insulation. Radiant foil usually is the most affordable type of insulation.
Foam Boards
Low in cost and easy to install, foam board insulation is generally made of polyurethane, polystyrene, or polyisocyanurate. Sheets of foam board can be cut to fit tightly between wall studs or attic ceiling joists. Because they are not as effective at insulating, foam boards are not as popular as blanket insulation.
However, foam boards don’t cause moisture accumulation and mold growth as can blanket insulation, because the solid foam doesn’t absorb much moisture. Instead, it dries in a relatively quick time frame.
What to Consider When Choosing the Best Attic Insulation
Finding the proper insulation for your home isn’t difficult once you’ve determined which type of insulation to purchase. If you’re wondering what is insulation made of or how to find the correct R-value for your geographic location, here’s what you need to know.
R-Value
Attic insulation ranges in effectiveness, so manufacturers and industry professionals typically reference insulation’s R-value to help people find the best attic insulation for their homes. R-value is a measurement of the insulation’s resistance to the flow of heat. The higher the R-value rating of a product, the more effective it is at reducing energy costs.
R-values for insulation are usually listed in the product description or on the product packaging. However, radiant foil insulation isn’t measured by R-value because it’s designed to reflect heat instead of reducing the transmission of heat. The optimal R-value for the insulation in your home also depends on your geographic location. Review this Energy Star R-value chart to learn the estimated R-value for your area.
Material
Insulation for attic spaces can be constructed from a wide range of materials, including cellulose, fiberglass, mineral wool, liquid polyurethane, and polystyrene.
- Cellulose insulation was used regularly in buildings for most of the last 100 years. This insulation material consists of cellulosic fibers like newspaper, cardboard, cotton, straw, hemp, and sawdust. At just 3.8 per inch of cellulose insulation, the R-value is relatively low.
- Fiberglass insulation is made from tightly woven fibers that are light, malleable, and relatively simple to cut and install. This material is regularly used in blanket insulation and has an R-value of 2.7 per inch.
- Mineral wool has an R-value of 3.3 per inch. It’s a stone-based mineral fiber insulation material that contains basalt rock and recycled steel slag.
- Liquid polyurethane is the main ingredient in spray foam insulation. The R-value of this type of insulation ranges from 3.5 per inch to 6.5 per inch, depending on whether you’re using open-cell (3.5) or closed-cell (6.5) spray foam.
- Polystyrene is used to create foam board insulation with a variable R-value of 3.8 per inch to 5 per inch, depending on whether it’s expanded polystyrene (styrofoam) or extruded polystyrene, which can be identified by the blue or pink color.
- Cotton is a very reliable insulation material for your attic and it is commonly made with recycled materials and is very easy to cut and install. This material is also safer than fiberglass during installation and use as there are fewer fibers floating around.
Tips for Installing Attic Insulation
Keep in mind that insulation cannot be installed just anywhere in your home. For instance, if blanket insulation is placed over air intake vents, the harmful particles can circulate through your home. Additionally, placing insulation near exposed electrical connections or over the top of heat vents could cause a fire.
Based on the type and style of the home, also consider how and where to place the insulation. Older homes and homes with wooden shingles may be built with a design that allows the natural evaporation of excess moisture. Insulation installed in these areas acts as a sponge, soaking up the moisture instead of allowing it to dissipate. As moisture builds up, mold can grow and eventually rot out the wood.
With blanket insulation, cut spaces in the insulation to allow it to fit around obstructions like drainage pipes, large water pipes, attic fans, and HVAC ducts. When blanket insulation becomes compressed, it’s less effective at insulating your home, such as when you forcibly install a piece of insulation around a pipe instead of cutting a gap to allow it to fit comfortably.
- Don’t install insulation over air vents, near electrical circuits, or in any other areas where it poses a risk.
- Carefully inspect older homes before installing insulation to ensure it won’t cause moisture accumulation that can lead to mold and rot.
- Blanket insulation is not as effective if it’s compacted during installation, so cut spaces for large drainage pipes and other obstacles instead of forcing the insulation to fit around them.
- Don’t install insulation in attics with moisture problems without first rectifying the issue. If you’re unsure if there’s moisture in the walls, use a moisture meter for detection, or call in a pro.
While laying insulation in attic spaces can be DIY-friendly, some situations require a professional insulation contractor. “If you’re a DIYer, you might be able to install your own insulation. However, there are a few situations where you should work with a pro,” advises Casolaro. “If you choose spray foam insulation, it’s tricky to install correctly without experience. Also, if your home is older, there’s a greater risk of exposed wires, moisture, and improper ventilation. A professional is more likely to recognize these issues.”
FAQs
Before investing in new attic insulation, take a look at these frequently asked questions regarding how to insulate an attic.
The best R-value depends on the typical temperature fluctuations in your city or state, but average R-value recommendations for attic spaces range between R-30 to R-49.
Spray foam insulation is the most effective type, with a maximum R-value of 6.5 per inch.
Yes, you can. If this occurs, moisture can become trapped inside the space, causing mold and air quality problems.
You can remove the old attic insulation before adding new insulation, but it isn’t necessary unless the old insulation is wet, made with hazardous materials (like asbestos), or simply degrading too quickly to serve any remaining purpose.
The rate at which attic insulation needs to be replaced depends on the type and whether or not you’ve experienced roof damage or pest infestations. Fiberglass and cellulose insulation can begin degrading 15 to 20 years after installation, while mineral wool, spray foam, and foam board can last for decades.
If your attic was previously poorly insulated, new insulation can greatly improve your home’s comfort levels and energy bills. The U.S. Department of Energy estimates that sealing air leaks and adding insulation can help households lower their heating and cooling costs by 20 percent.
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