Attic insulation cost

How much does attic insulation cost?

The price is blown cellulose in an open attic, brought up toward a planning R-value that depends on your city’s climate zone. It is not closed-cell foam on the underside of the roof, not wall insulation, and not a kneewall someone has to frame before the hose comes out. The national shape of the price is about $1.70 per square foot of attic in a middle zone, with about 55 percent of that as labor, then a zone multiplier and your city’s labor factor. The low column is 78 percent of the scaled typical. The high column is 134 percent. Low is an easy hatch and almost nothing in the way. High is the same cellulose when the hatch is a closet ceiling, the eaves need baffles, or a little old material has to be raked. Knob-and-tube wiring, vermiculite, a wet attic, or a full removal before the new blow can sit above the high number. Those are different jobs.

The R-value this site uses

Zone 1 uses a planning target of R-30. Zones 2 and 3 use R-49. Zone 4 and colder use R-60. Those targets exist so a Phoenix attic and a Minneapolis attic are not priced as the same pile of bags. They are not a promise that your inspector will require that number. Confirm the energy code on the house before you treat the target as law. A colder zone uses more material in this model, which is why the national starting point moves before labor even starts. Your city then moves the crew.

Square footage in the bar is treated as attic area. That is fair for a simple one-story house and only a sketch for a two-story, where the attic is smaller than the floor. If you know the attic is half the floor, do not use the full number and then accuse the quote of being high. Set a closer area. The calculator will not guess your stairs.

What you should ask before you compare

What R-value is up there now? What R-value will they leave? Is air sealing at the hatch, the wire holes, and the bath fan included, or is this only bags? A top-up over a decent layer is the typical column. A quote that foams the roof deck is not on this page at all. Foam can be the right job in a finished attic or a hot roof. It is a different price, and mixing it into a cellulose table is how both numbers become useless.

What insulation does not change

It does not change the furnace sticker or the roof price. It can change the yearly bill, which is a separate calculator that uses degree days and the electric rate. Do not let someone add “you’ll save it back” onto the install price with no yearly number attached. This page does not promise a payback, and it does not assume a rebate.

If you rent

Blowing an attic is the owner’s project. Use the range to read a proposal for the building. Do not hire a crew for an attic you do not own. Owners of a house that does not match the city example should set their own square footage. Reviewed as a method on 2026-09-30. The city page writes the target R, the labor factor, and the local housing note in one place so the national $1.70 is not the last word.

If the quote will not say the starting R-value and the ending R-value, you do not have a scope. You have a number of bags. Bags without an R-value cannot be compared with this table, in any city.