How much insulation do I need?

For walls or an attic floor. Check the package label for how many square feet one bag or roll covers, and enter it below.

Length (ft)Width or wall height (ft)Sq ft per package (sq ft)

Packages to buy

9 packages

Area to cover320 sq ft

Estimated material cost

Packages to buy

9 x $$45.00 per package

$405

Estimated total$405

Typical store prices before tax and delivery. Change any price to match your store.

How to measure

For walls, measure the length and height of the walls to insulate. For an attic, measure the length and width of the attic floor. Read the package label for the square feet each one covers.

Tips from the field

Coverage on the label changes with the R-value. Thicker, higher R-value batts cover less per bag.
Includes 5% extra for trimming around pipes, wires, and odd framing.

What you'll need

Fiberglass battsBlown-in insulationUtility knifeDust masks and gloves

Common questions

What R-value do I need?

It depends on your climate zone. Hot climates like the Gulf Coast usually call for R-30 to R-49 in attics and R-13 to R-15 in 2x4 walls.

Batts or blown-in for an attic?

Blown-in fills gaps better in attics with lots of wires and framing. Batts are easier for a DIYer without a blowing machine.

Do I need a vapor barrier?

It depends on your climate. In hot, humid areas, a vapor barrier on the inside of walls can trap moisture. Check local code.

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