What should your insulation project cost?
A budgeting range from national per-square-foot pricing — before rebates, which in many states cover a large share of this work.
National ranges from published contractor-marketplace pricing. Removal of old insulation, tight access, and deep R-value targets push toward the high end; topping up an accessible attic sits near the low end.
This is an estimate, not an eligibility determination. Program rules, coverage limits, and available funding vary. Check the state program page and Rebate Matcher before planning around an incentive.
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What's next
What moves an insulation quote
Per-square-foot math is the start. These items explain why two quotes for the same attic can differ by thousands.
Air sealing first
The attic floor should be sealed before insulation goes in — it's often a separate line item, and it's the one that makes the insulation perform. See what you can DIY vs hire out.
Removal and prep
Old, damaged, or pest-contaminated insulation has to come out first. Removal, baffles, ventilation chutes, and hatch work all add real cost.
Access
A walkable attic with a real hatch is cheap to work in. Tight kneewall spaces, finished attics, and brick exteriors (for wall work) are not.
Health & safety items
Knob-and-tube wiring, recessed lights that need covers, and bath fans venting into the attic must be handled before insulating. Good contractors quote this; bad ones bury it.
Why cellulose is the retrofit default
Dense-packed or loose-blown cellulose fills irregular cavities, buffers moisture, resists air movement better than loose fiberglass, and is usually the cheapest material per R. It's the standard choice for existing homes — our cellulose guide covers why. For the full material and location breakdown, see insulation costs and the attic cost deep-dive.
Many programs cover 40–100% of this work
Envelope work is the most heavily subsidized part of a retrofit. State and utility efficiency programs frequently cover a large share of insulation and air sealing — in the strongest programs, most of the bill. The number above is the before-rebate price; your real number depends on your state and sometimes your income. Match your rebates before you collect quotes, and check your state page for program specifics.
Insulation cost questions
Is blown-in insulation cheaper than batts?
Usually, for retrofits. Blown-in cellulose and fiberglass run roughly $0.50–$2.50 per square foot installed in an attic, while professionally installed batts can run higher once labor is included — and blown-in fills gaps and odd cavities that batts leave open. Batts make more sense in open, regular framing.
How much does it cost to insulate a 1,500 sq ft attic?
Using national per-square-foot ranges, a 1,500 sq ft attic with blown-in cellulose typically lands between roughly $900 and $3,500 installed, depending on how much insulation is already there, access, and whether old material needs removal. Air sealing first is usually quoted separately.
Does insulation pay for itself?
Attic insulation is consistently one of the highest-return home upgrades because the material is cheap relative to the heat it stops. Payback depends on your fuel, climate, and starting point — a nearly empty attic in a cold state pays back fastest. Rebates shorten it further, often dramatically.
Should I air seal before insulating?
Yes, always. Blowing insulation over an unsealed attic floor buries the leaks and makes them harder to fix later. Air leaks can carry far more heat than conduction through the insulation itself, so sealing first makes every inch of new insulation perform as rated.
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Most states pay for part of this. See your programs.
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