Ashburn, VA

How Much Does Attic Insulation Cost?

$1.50 – $3.00 per square foot

On average, most homeowners spend between $813 and $1492 or $1.50 to $3.00 per square foot to install attic insulation. Pricing depends on the size of your attic, the type of insulation material used, and labor rates. For example, blown-in insulation for an attic in a 1,200 square foot home costs about $1,850. Get free estimates from insulation companies near you.

Attic Insulation Cost

On average, most homeowners spend between $813 and $1492 or $1.50 to $3.00 per square foot to install attic insulation. Pricing depends on the size of your attic, the type of insulation material used, and labor rates. For example, blown-in insulation for an attic in a 1,200 square foot home costs about $1,850, but this price does not include the cost to remove any old insulation.

Attic Insulation Cost
National Average Cost $1,850
Minimum Cost $800
Maximum Cost $2,800
Average Range $813 to $1,492

Table Of Contents

  1. Attic Insulation Cost
  2. Batts, Blankets and Rolled Insulation Cost
  3. Blown-In Attic Insulation Cost
  4. Spray Foam Insulation Cost
  5. Loose-Fill Attic Insulation Costs
  6. Alternative Attic Insulation Options
  7. What is the R-value?
  8. Tax Credits and Rebates
  9. Home Energy Audit
  10. Hiring An Attic Insulation Contractor
  11. Attic Insulation Companies

Average Attic Insulation Cost Per Square Foot

On average, attic insulation costs between $1.50 and $3.00 per square foot depending on the type of materials used and the R-value per inch of those materials. Attic insulation will help keep your energy bills down, whether you need to stop heat coming in from outside or prevent the heat in the house from escaping. When the insulation is inadequate, the life of your HVAC (Heating, ventilation, and air conditioning) system will be shortened, because it will be working for more hours per day than needed.

Attic Insulation Cost By Type

When installing attic insulation, there are a few options to choose from. Blown-in insulation is the least expensive option and is the most popular choice for old attics. Spray foam is the most expensive but is the most popular choice for newer homes and new construction. When hiring an attic insulation installer, expect to pay between $65 and $85 per hour for labor.

Attic Insulation Cost Per Square Foot
Insulation Type Materials Cost Per Square Foot
Batts, Blankets and Rolled $0.65 – $1.41
Blown-In $0.83 – $0.91
Spray Foam $0.45 – $1.50 per board foot
Loose-Fill $1.00 – $1.25
Radiant Barriers $0.25 – $0.50

Attic Insulation Cost Savings

According to the US Department of Energy, a homeowner can expect to save 10% to 50% on utility bills—depending on how inefficient the old insulation is and what the R-value is of the insulation you are having installed. Your insulation project cost will be offset over time by how much you can expect to save on your air conditioning expenses.

Attic Insulation Removal Cost

If you are replacing existing insulation in your home, then you will have to pay for its removal. Expect to pay professionals $1 per square foot for insulation removal, but this cost could be lower if you are adding that service to the quote for the new insulation. As with installing it, removing old blow-in insulation could produce dust that requires you to stay out of the home for three days.

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Batts, Blankets and Rolled Insulation Cost

Of all the types of products available for insulation, batts and blankets are the most commonly used because homeowners can use it to insulate their attics without the need for special equipment or any great depth of expertise. It is purchased in rolls of a convenient size and weight, which also makes installation easy.

Batts and blanket insulation materials are available with facing: a layer of either plastic or paper which is attached to the insulation and allows the product to be stapled to hold it in position.

Batt Insulation Cost Per Square Foot

Insulation Type R-Value Per Inch Cost Per Square Foot
Fiberglass R3–R4 $0.65 – $1.20
Rockwool R3–R4 $0.75 – $0.85
Cotton R3.5–R4 $0.76 – $1.41
  • Batts are typically available in widths of 15” and lengths from 48”–97”. 
  • Blankets are sold in rolls which also come in widths of 15”—to allow them to fit in the space (cavity) between the joists. Like batts, the length of the roll will vary, in this case from 25’–40’.

Attic Insulation

Fiberglass Insulation Cost

Fiberglass insulation costs between $0.65 and $1.20 per square foot with an R-value of R3–R4 per inch of thickness. When installing fiberglass insulation, be sure to cover up any exposed skin and wear a mask at all times.

Rockwool Insulation Cost

Rockwool insulation costs between $0.75 and $0.85 per square foot with an R-value of R3–R4 per inch of thickness. Rockwool, as the name might suggest, is made from stone. Its temperature maintenance properties are derived from the capability of the stone lava fibers to trap tiny pockets of air within the product’s structure. The air that gets trapped creates a barrier which works with the fibers to keep hot air out and cold air in.

In addition to its insulation properties—which are slightly higher than fiberglass—it is also able to withstand temperatures over 1,000 degrees and provides a layer of soundproofing from outside noise. In its installation, it does not require staples to hold it in place since it will generally spring into shape filling the spaces you need it in. In contrast to fiberglass insulation, it does not cause skin irritation or require the contractor to wear protective gear.

Cotton Insulation Cost

Cotton batts insulation costs between $0.76 and $1.41 per square foot with an R-value of R3.5–R4 per inch of thickness. Cotton batts, also known as “blue jeans,” doesn’t cause any health concerns, is formaldehyde free, and it's processed with as much as 85% recycled fibers. It is also treated with borate fire retardant, which in addition to making it safer, acts as a repellent to certain insects.

Cotton batts have a low density, and as a result, does an excellent job of not allowing much transfer of heat from the air above the insulation to the air below—thermal conductivity. Unfortunately, it is not readily available everywhere.

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Blown-In Attic Insulation Cost

The average cost of blown-in insulation to achieve an R-value of R-38 to R-49 is $1,665 with most homeowners spending between $874 and $2,156 or $1.59 per square foot.

Blowing in loose-fill insulation is easier than laying rolls—it blows into tight spaces where the slope of the roof meets the perimeter walls, and also gets around any plumbing pipes or electrical work. Installation is a little more difficult than directing the hose and monitoring the height or thickness of the layer as it is distributed in the attic space.

Blown-In Fiberglass Insulation In Attic

Blown-in insulation is sold in tightly filled bags which are opened onsite and fed into a blower. This pipes in the loose material through a large hose, allowing the installer to direct the flow wherever it is needed. When blowing in, the process can generate an irritating degree of airborne dust, which requires the installer to use a breathing mask while doing the work.

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Spray Foam Insulation Cost

Spray foam insulation is available in two different types. Open-cell polyurethane costs $0.45 to $0.65 per board foot and has an R-value of R-3.5 to R-3.7 per inch. Closed-cell spray foam costs $1 to $1.50 per board foot and has an R-value of R 6.0 to R 6.5 per inch.

  • One of the most expensive options available
  • Solid and water resistant
  • Foam can be sprayed into both horizontal and vertical attic spaces

Attic Insulation Blown-in Spray Foam

Types of spray foam insulation

  • Open-cell polyurethane – R 3.5–R 3.7/inch, $0.45–$0.65/board foot. Open-cell polyurethane insulation stops the movement of air in your attic space, but it requires a vapor barrier in some installations because it can allow moisture to pass through. Also known by the name “half-pound foam,” it does come with health concerns: during the process of spraying this foam into your attic space, various volatile organic compounds (VOCs) and chemicals are released into the air.
  • Closed-cell polyurethane – R 6.0–R 6.5/inch, $1–$1.50/board foot. Closed-cell polyurethane is the most efficient material for insulation available, but it also releases VOCs during installation. R-value has a price tag to match when compared to open cell foam. With a density of two pounds per cubic foot in an attic space, closed cell foam will create a barrier that is very resistant to water, has a low Perm (moisture vapor permeability) rating, and is very effective against the movement of air.
When used in walls, the strength and rigid nature of closed-cell polyurethane foam is known to double or triple the walls’ ability to resist wind loads—known as racking strength.

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Loose-Fill Attic Insulation Costs

The average cost of loose-fill attic insulation is $1 per square foot and it the most popular choice among homeowners. When the insulation is being added to or replacing the insulation in an existing home, loose-fill will have an advantage over batts or blankets. Loose-fill insulation is usually made of fiberglass or cellulose.

Fiberglass

Fiberglass insulation typically contains around 30% recycled glass. At approx. $1 per square foot and an R-value of R 2.2–2.7/inch, it is a popular option for many homeowners who are insulating their attic space. It can be used as the only insulation product or blown in over existing cellulose loose-fill. It won’t settle or become compressed over time and fiberglass cannot be damaged by water so it will not need a moisture barrier when used next to a wall or over an air-conditioned space.

Once blown into your attic space, the product could have a fluffy structure because of a lack of density, which will result in a drop in its overall effectiveness. This could be remedied by the top surface being topped with a denser loose-fill application, or insulation blanket products.

Cellulose Insulation Cost

Cellulose loose-fill insulation is among the oldest forms of materials used in building insulation applications. It costs between $1.20 and $1.25 per square foot and provides an R-value of R-3.2 to R-3.8 per inch. Despite being made from newspaper that burns very quickly, compared to fiberglass, cellulose insulation is much denser, so it dramatically limits the flow of oxygen to a fire. In most cases, 80% or more of the materials used for cellulose insulation are recycled.

In spite of the R values of each product, it has been said that compared to fiberglass, loose-fill cellulose can perform 20% to 30% better at reducing energy expenses.

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Alternative Attic Insulation Options

Cost Of Radiant Barriers

The average cost of radiant barriers is $0.50 per square foot installed. A common sight in residential attics in hotter climates is the addition of radiant barriers, which are to reduce heat gain during the summer months and thereby drive down utility costs related to cooling expenses.

  • $0.10–$0.25/sqft for single-sided barrier or $0.15–$0.50 for double-sided barrier—if you are buying rolls to install yourself 
  • Installing a single-sided barrier in a 1,500 sqft. attic, the material costs are between $150 and $375, and for a double-sided barrier, prices are between $225 and $750.

Radiant barriers block heat transfer by reflecting heat energy instead of absorbing it like traditional insulation products. The standard measurement used to rate insulation performance, the R-value, does not apply to radiant barriers. These barriers are made using a very reflective material like aluminum foil.

Instead of absorbing heat, a radiant barrier works by reflecting direct sunlight out of your roof rather than absorbing it into the attic space by conduction. When the radiant energy hits the radiant barrier at a perpendicular angle, the barrier will reflect the heat away best.

Many homeowners will elect to install a radiant barrier as a second layer of protection having already installed batts, blankets, loose-fill, or spray foam in the attic floor.

Structural Insulation Panels

Foam insulation is attached to plywood to form a structural panel. These panels are energy efficient, inexpensive, and can be built for any type of home or attic.

Reflective Insulation

Reflective insulation is a layer of aluminum foil added to insulation to prevent radiant heat from entering the attic. This type of insulation works best in small attic areas and can be more effective if used correctly.

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What is the R-value?

The R-value is a rating system that tells you how an insulation material performs in resisting the conduction of heat flow—the thermal resistance. The higher the number = the greater the effectiveness of the insulation = the higher the energy savings.

When insulation is being installed in a multi-layered format, the values of each layer get added together to give the final R-value for the space being insulated.

The conditions that affect the R-value of an insulation product include:

  • Type - Some insulation products will deteriorate over time because of age, how heat will affect them, and the accumulation of moisture in the attic.
  • Thickness - The more insulation you have in your attic space, the higher the protection from heat loss or heat gain.
  • Density - Over time, depending on which type of insulation is installed, some products (like loose-fill insulation) will settle and become denser under their own weight, but this increased density caused by compression does not increase the R-value or effectiveness. Insulation that has been compressed to the point where it reduces or prevents air flow actually hurts the efficiency of the insulation’s ability to prevent heat transfer.

Attic Insulation Energy Efficiency Audit

What Is The Best R-Value For Insulation?

Before hiring an insulation company, look up the R-value your attic should have on the US Department of Energy’s website. Split into seven regions, the map’s recommendation for your area comes from a combination of factors, including the type of cooling and heating system in your home, the part of the house that is to be insulated, and the local climate.

A loose guide to minimum R values includes the following recommendations:

  • Cold climates - R 49
  • Temperate climates - R 38
  • Hot climates - R 30

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Tax Credits and Rebates

Many federal tax credits for energy efficiency focus on upgrades and enhancements. Energy Star states that “Adding adequate insulation is one of the most cost-effective home improvements that you can do.”

The most recent tax credit amount is 10% of the cost, up to $500, not including installation, of typical bulk insulation products such as batts, rolls, blow-in fibers, rigid boards, expanding spray, and pour-in-place.

Products that air seal (reduce air leaks) can also qualify, as long as they come with a manufacturer's certification statement, including:

  • Weatherstripping
  • Spray foam in a can, designed to air seal
  • Caulk designed to air seal
  • House wrap

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Home Energy Audit

How good is your attic insulation?

To get an accurate answer to this question, you will need to invest in an energy audit. On average, this will cost around $350, and the results from the audit will tell you if there are energy efficiency problems, and exactly where they are in the home.

When homeowners act on the findings, the resulting savings on utility expenses can be as high as 30%. On the other hand, an audit could save you from the expense of replacing your insulation—if that is not the reason for your HVAC not performing as effectively or efficiently as it should.

What tests are performed in an energy audit?

The types of tests carried out in an energy audit will include:

  1. Energy bill audit – Compares your utility bills for the previous 12 months with those from similar sized homes near where you live.
  2. Infrared camera - Handheld infrared camera equipment reads the temperature in different locations in each room, which will tell where heat is getting in or out.
  3. Blower door test - Determines how airtight your home is by manipulating the air pressure in the house by attaching a massive fan to your front door and blasting it at full power to discover any leaks in your doors, windows, and attic.

Generally, you would need to set aside between 2 to 3 hours for the audit, depending on the size of your home. The audit may also find that you have highly inefficient bulbs, as well as appliances—because of their age.

Many contractors that specialize in eco-friendly products can have great advice on how to upgrade your home to make it more energy efficient, and they’ll know what to recommend for your attic insulation project once they can see the layout.

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Hiring An Attic Insulation Contractor

When choosing from a list of contractors to install your attic insulation, hire a contractor that meets these criteria.

  • Licenced, insured and bonded
  • High ratings on the BBB, HomeGuide, and Google
  • Many years of experience installing attic insulation
  • Warranty and guarantee on parts and labor

Get free estimates on HomeGuide from trusted attic insulation contractors:

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