How Much Does Attic Insulation Cost in Seattle? (2026 Guide)
Quick Answer: What Attic Insulation Costs in Seattle (2026)
For a typical Seattle-area home with 1,000 to 1,500 sq ft of attic space, you’re looking at $1,500 to $4,125 for blown-in insulation installed to R-49. Spray foam runs $3,000 to $11,250 for the same area. And here’s the good news: utility rebates from PSE and Snohomish PUD can knock 30 to 50% off your out-of-pocket cost.
Key takeaway: Blown-in cellulose or fiberglass is the most cost-effective choice for Seattle attics. Spray foam costs 2 to 3x more and really only makes sense when air sealing is a primary concern.
Cost by Insulation Type
| Insulation Type | Cost Per Sq Ft | 1,000 Sq Ft Attic | 1,500 Sq Ft Attic | R-Value Per Inch |
|---|---|---|---|---|
| Blown-in cellulose | $1.50–$2.50 | $1,500–$2,500 | $2,250–$3,750 | R-3.5–R-3.7 |
| Blown-in fiberglass | $1.50–$2.75 | $1,500–$2,750 | $2,250–$4,125 | R-2.5–R-3.0 |
| Fiberglass batts | $1.25–$2.25 | $1,250–$2,250 | $1,875–$3,375 | R-3.0–R-3.7 |
| Spray foam (open-cell) | $3.00–$5.00 | $3,000–$5,000 | $4,500–$7,500 | R-3.5–R-3.7 |
| Spray foam (closed-cell) | $5.00–$7.50 | $5,000–$7,500 | $7,500–$11,250 | R-6.0–R-7.0 |
These ranges cover materials and professional installation. Your actual number will depend on a few things specific to your home, which we’ll get into below.
Want something more precise? Use our insulation cost calculator to get an instant estimate based on your home’s details, no contact info required.
Cost by Project Scope
Not every project is a simple install-and-done situation. Here’s how the scope of work affects your total:
| Project Scope | Cost Per Sq Ft | Typical Total (1,200 sq ft) |
|---|---|---|
| Add insulation on top of existing | $1.50–$2.75 | $1,800–$3,300 |
| Full removal + new blown-in | $2.50–$4.50 | $3,000–$5,400 |
| Batt removal + new blown-in | $2.75–$4.75 | $3,300–$5,700 |
| Air sealing + blown-in | $2.00–$3.50 | $2,400–$4,200 |
| Rodent cleanup + new insulation | $3.50–$6.00 | $4,200–$7,200 |
What Drives the Cost Up or Down
Square Footage
This is the single biggest factor. A 900 sq ft attic costs less than a 2,000 sq ft attic, no surprise there. One thing to keep in mind, though: your home’s living square footage and your attic square footage are often different numbers. Homes with complex rooflines or partial attic areas can throw you off if you’re trying to estimate on your own.
Current Insulation Condition
If your attic has old, contaminated, or compressed insulation that needs to come out first, expect removal costs of $1.00 to $2.00 per square foot on top of the new installation. We see this a lot in older Seattle homes built before the 1990s. The original insulation has usually settled over the decades, picked up moisture damage, or been torn up by rodents.
R-Value Target
Washington state energy code requires R-49 for attic insulation. Here’s what that looks like in practice:
| Material | Thickness for R-49 | Thickness for R-38 |
|---|---|---|
| Blown-in cellulose | ~13–14 inches | ~10–11 inches |
| Blown-in fiberglass | ~16–20 inches | ~12–15 inches |
| Fiberglass batts | ~13–16 inches | ~10–12 inches |
Most homes built before 2000 in King County sit at R-19 to R-30, which is well below current code. Bringing your attic up to R-49 is the standard for any professional installation in 2026.
Accessibility
Attics with low clearance, limited access points, or lots of obstacles like HVAC ducts, wiring, and plumbing penetrations take more labor time. If your installer has to army-crawl to reach the far corners of your attic, that’s going to show up in the price.
Material Choice
Blown-in cellulose and fiberglass are by far the most common choices for Seattle attics. If you’re weighing the options, we put together a detailed comparison in our guide on blown-in vs. batt insulation for Seattle homes.
Removal + Replacement vs. Adding On Top
Adding on top is the most budget-friendly approach if your existing insulation is in decent shape, meaning no contamination, no moisture damage, and not severely compressed. You only pay for the new material and installation.
Full removal is necessary when:
- Rodent droppings or nesting material are present
- Insulation is water-damaged or moldy
- Old vermiculite insulation is present (potential asbestos concern)
- Insulation is so compressed it’s barely providing any R-value
After attic cleanup and rodent remediation, insulation replacement is usually the logical next step.
Rebates That Reduce Your Cost
This is where Seattle-area homeowners have a real leg up. Utility rebates can take a serious chunk off your final bill:
| Utility Provider | Service Area | Rebate Type | Potential Savings |
|---|---|---|---|
| Puget Sound Energy (PSE) | Parts of King County | Insulation rebate program | Up to 50% of project cost |
| Snohomish PUD | Snohomish County | Weatherization program | Varies by income/project |
| Cascade Natural Gas | Gas-heated homes | Weatherization incentive | Varies by project |
Pro tip: We help homeowners navigate these rebate programs on every insulation project. The paperwork can be a headache, so we handle it for you.
Calculate your insulation cost to see your estimated price, then ask us about which rebates apply to your home.
How Long Does Installation Take?
| Attic Size | Install Only | Removal + Replace |
|---|---|---|
| Small (under 1,000 sq ft) | 2–4 hours | 6–8 hours |
| Medium (1,000–1,500 sq ft) | 4–6 hours | 8–12 hours |
| Large (1,500+ sq ft) | 6–8 hours | 10–16 hours |
Most projects wrap up in a single day. You don’t need to leave your home during installation, though fair warning: the blower machine gets pretty loud.
When to Insulate Your Attic
Insulation works year-round in the Pacific Northwest. Unlike exterior projects, attic insulation doesn’t depend on the weather. Here are the most common reasons Seattle homeowners reach out to us:
- High energy bills, especially once winter heating kicks in
- Uneven room temperatures, like upstairs rooms that are noticeably warmer or cooler than the rest of the house
- Home inspection findings, whether you’re buying or selling and need to address insulation gaps
- Rodent remediation, because after attic cleanup, replacing the insulation is usually the next step
- Rebate deadlines, since utility programs run on annual budget cycles and funds do run out
ROI: Does Attic Insulation Pay for Itself?
| Metric | Typical Range |
|---|---|
| Annual energy savings | 15–25% of heating/cooling costs |
| Average annual savings (Seattle home) | $200–$600 per year |
| Payback period | 3–7 years |
| Home value increase | $1,000–$3,000+ |
| Lifespan of blown-in insulation | 20–30+ years |
The Department of Energy consistently ranks attic insulation as one of the highest-ROI home improvements you can make. When you factor in 20 to 30 years of energy savings, it’s hard to find a better return.
Get a Real Number for Your Home
We built our insulation cost calculator because we think you should know what a project costs before you pick up the phone. Plug in your attic size, insulation type, and whether you need removal, and you’ll get an instant range.
When you’re ready for an exact quote, get your free estimate. We’ll come out, look at your attic, confirm the scope, and give you a written price. No pressure, no upsell games.
We provide attic insulation installation throughout King County and Snohomish County, with teams serving Kent and South King County and the greater Puget Sound region.
"The biggest thing that moves the price is what's already up there. If we're pulling out old fiberglass or cleaning up rodent damage first, that adds real labor. But when the attic is clean and accessible, the install itself is straightforward and the cost reflects that."
Sadeq, Owner
"Most attic insulation jobs take us a single day. People expect it to be this big multi-day project, but if the prep work is done right, we're usually blowing insulation by mid-morning and wrapping up by afternoon. That's for a typical 1,200 square foot attic."
Sadeq, Owner
Frequently Asked Questions
How much does attic insulation cost in Seattle?
For a typical Seattle-area home with 1,000 to 1,500 sq ft of attic space, blown-in insulation installed to R-49 runs $1,500 to $4,125. Spray foam costs $3,000 to $11,250 for the same area. Utility rebates from PSE and Snohomish PUD can reduce your out-of-pocket cost by 30 to 50 percent.
What R-value does my attic need in Seattle?
Washington state energy code requires R-49 for attic insulation. Most homes built before 2000 in King County only have R-19 to R-30, so there's a good chance your attic is under-insulated. Any professional install in 2026 should bring you up to that R-49 standard.
Should I remove old insulation or just add more on top?
If your existing insulation is in decent shape, with no contamination, moisture damage, or heavy compression, adding on top is the most cost-effective option. Full removal is necessary when there are rodent droppings, water damage, mold, old vermiculite, or insulation so compressed it's barely doing its job.
Are there rebates for attic insulation in Seattle?
Yes. Puget Sound Energy offers insulation rebates that can cover up to 50 percent of the project cost. Snohomish PUD and Cascade Natural Gas also have weatherization programs. These rebates can seriously reduce what you pay out of pocket.
How long does attic insulation installation take?
Most install-only jobs take 2 to 8 hours depending on attic size. If old insulation needs to be removed first, plan on 6 to 16 hours. Either way, the vast majority of projects wrap up in a single day.
Does attic insulation pay for itself?
It usually does within 3 to 7 years. Seattle homeowners typically see 15 to 25 percent savings on heating and cooling costs, which works out to roughly $200 to $600 per year. Blown-in insulation lasts 20 to 30 years or more, so the long-term return is strong.