Blown-in Insulation Calculator

Q: How much does blown-in insulation cost?

Blown-in insulation costs $1 to $3 per square foot professionally installed, with most homeowners paying $1.50 to $2 per square foot for an attic. A 1,000 sq ft attic blown to R-38 runs $1,500 to $3,000 installed. DIY runs $0.50 to $1 per square foot in materials alone, since you skip the labor to set up and run the machine.

Blown-in insulation costs $1.00 to $3.00 per sq ft installed for a typical attic, with most homeowners landing at $1.50 to $2.00 per sq ft. A 1,000 sq ft attic blown to R-38 runs $1,500 to $3,000 installed, or $800 to $1,500 in DIY materials. Use the calculator to get bags needed, insulation depth, and total cost for your attic.

Estimated total—

Your attic

Attic area

Unit

sq ftm²

Material & R-value

Price assumptions

Bag price ($) Pro installed ($/sq ft)

Defaults & assumptions

Defaults: a 1,000 sq ft attic, cellulose blown to R-38, and US national average rates. Adjust the material, R-value target, and rates above to match your project. The pro installed price assumes a crew brings the machine; DIY assumes you rent a machine for $50 to $100 per day.

Enter your attic area above to see results.

Blown-in insulation cost per square foot

Blown-in insulation is the cheapest way to bring an attic up to code or improve energy efficiency. The biggest line item is labor to set up the machine and feed the hose, which is why pro installation averages $1.50 to $2.50 per sq ft but DIY runs only $0.50 to $1.00 per sq ft in materials. Cellulose is the cheapest material at $15 to $20 per bag and covers about 19 cubic feet; fiberglass runs $25 to $35 per bag and covers 25 cubic feet. Bag count depends on the R-value target: R-38 needs about 12 inches of cellulose, R-49 about 15 inches. The right target for your climate is R-30 in warm southern US, R-38 across the middle band, and R-49 or higher in cold northern climates.

Typical blown-in attic insulation cost (R-38 cellulose, US averages)
Attic size	DIY materials	Professionally installed
500 sq ft	$300 to $500	$500 to $1,200
1,000 sq ft	$600 to $1,000	$1,000 to $2,400
1,500 sq ft	$900 to $1,500	$1,500 to $3,600
2,000 sq ft	$1,200 to $2,000	$2,000 to $4,800

How the calculator works

Insulation depth = target R-value ÷ R-per-inch of the material. Cubic feet of insulation = attic area × depth in feet (inches ÷ 12). Bags needed = cubic feet ÷ one bag’s coverage, rounded up since you can’t buy a partial bag. Cost is bags times your local bag price for DIY. For pro installed cost, the rate you enter is treated as the price for the selected material at R-38; the calculator scales it by attic area and by how the target depth compares to that R-38 baseline, so a higher R-value costs proportionally more to install. Picking a material prefills its typical rate. Price ranges reflect published US averages from national cost guides (Angi, HomeGuide, HomeAdvisor, 2026).

Blown-in insulation cost FAQ

How much does blown-in insulation cost?

Blown-in insulation costs $1.00 to $3.00 per sq ft professionally installed, with most homeowners paying $1.50 to $2.00 per sq ft for an attic. A 1,000 sq ft attic blown to R-38 runs $1,500 to $3,000 installed. DIY runs $0.50 to $1.00 per sq ft in materials alone, since you skip the labor to set up and run the machine.

How many bags of blown-in insulation do I need?

Divide your attic area in square feet by the coverage per bag (typically 30 to 50 sq ft per bag at R-38 for cellulose, depending on bag size). For a 1,000 sq ft attic at R-38 with cellulose, you need about 50 to 60 bags. Add 5 to 10 percent extra for variations in joist depth.

What R-value do I need for my attic?

R-30 for warm southern US (zones 1 to 2), R-38 across the middle band where most US homes sit (zones 3 to 4), and R-49 or higher in cold northern climates (zones 5 to 7). The EnergyStar recommendation is roughly R-38 to R-60 depending on where you live. Going above R-60 is rarely cost-effective for most homes.

Can I install blown-in insulation myself?

Yes. Rent a blowing machine from a home improvement store for $50 to $100 per day, buy 50 to 60 bags of cellulose at $15 to $20 each, and have a helper feed the machine while you run the hose. DIY runs $800 to $1,500 for a typical 1,000 sq ft attic at R-38. The main trade-off is the physical work and a few hours of your time versus paying a crew $700 to $1,500 in labor.