Attic insulation and ventilation cost
Adding attic insulation, fixing gaps and damage, and repairing attic vents and fans.
Attic insulation keeps heat in during winter and out during summer. Over time it can settle, get pushed aside during work in the attic, or never have been deep enough.
Attic vents let heat and moisture out. Insulation and ventilation work together, so this page covers both, plus attic and whole house fans and insulation missing from walls.
What our reports priced these at
| Work | Most homes | Middle price | Based on |
|---|---|---|---|
| Add insulation to reach the right depth | $450 to $2,380 | $1,400 | The 7% of homes where it was priced |
| Add attic insulation where it's missing | $300 to $480 | $470 | Limited number of homes |
| Fix displaced attic insulation | $200 to $840 | $440 | Limited number of homes |
What HomeCloud reports priced this fix at in homes we evaluated Sep 2025 to Oct 2026. The range is the middle half of homes; the middle price is the median. Your price comes from a written estimate for your home. Attic vent and fan repairs were too rare in the sample to show a range.
What affects the price
- Attic size
- Insulation is priced by area, so a bigger attic costs more.
- How much to add
- Topping up a thin layer costs less than adding a lot of depth across the whole attic.
- Type of insulation
- Blown-in insulation is quick to add over existing insulation. Batts, the pre-cut rolls, suit some spaces better. Spray foam costs more.
- Access
- Low roof slopes, small hatches and floored attics take longer to work in.
- Vents and baffles
- Adding vents, or baffles that keep insulation away from the vents at the roof edge, adds to the job.
Common questions
How much attic insulation do I need?
It depends on your climate zone. For an attic with little or no insulation, ENERGY STAR recommends R-49 in Zones 2 and 3 and R-60 in Zone 4. If the attic already has 3 to 4 inches, it recommends adding R-38 in Zones 2 and 3 and R-49 in Zone 4. The Atlanta area is Zone 3 and the Dallas-Fort Worth area is Zone 2 or 3, so R-49 is the target there. Raleigh-Durham, Charlotte and Greensboro sit near the line between Zones 3 and 4, so aim for at least R-49, and R-60 if your county is in Zone 4. In depth, R-49 is about 20 inches of blown fiberglass or about 13 inches of blown cellulose. See types of insulation for more.
Can I add new insulation on top of old?
Usually, if the old insulation is dry and clean. Wet, moldy or pest-damaged insulation is removed first.
More insulation and ventilation resources
Other insulation and ventilation repairs
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