How Much Does Home Insulation Cost in Seattle? 2026 Price & Rebate Guide

Insulation cost by area of the home

Where the insulation goes drives the price more than anything else. Topping up a typical 2,000-square-foot attic from R-19 to R-49 with blown-in fiberglass or cellulose runs about $3,500–$5,500 in Seattle, which is 20–30% above the statewide average because of local labor rates. Insulating a 1,000-square-foot crawl space floor to R-30 costs $3,000–$7,000, and a full crawl-space encapsulation with a vapor barrier and R-10 wall insulation runs $4,000–$9,000. Dense-packing existing exterior walls through small holes costs $3,000–$6,000 for an average home, sealing and insulating the rim joist with closed-cell foam is $500–$1,500, and a whole-home air-seal-and-insulate package lands at $8,000–$15,000. Air sealing on its own, which should come before any new insulation, runs $500–$2,000.

Cost by insulation type

Installed prices per square foot in Western Washington run roughly $0.50–$1.20 for fiberglass batts, $0.80–$1.60 for blown-in fiberglass or cellulose, $1.20–$2.00 for mineral wool, $1.00–$2.50 for rigid foam board, $0.80–$1.80 for open-cell spray foam and $1.50–$3.50 for closed-cell spray foam. Blown-in products win on open attics because they fill around wiring and framing without gaps. Closed-cell foam costs the most but adds structural rigidity, blocks moisture and air-seals in one step, which is why we specify it for rim joists, crawl-space walls and low-slope roofs where there is no room for depth. Mineral wool earns its premium in walls between living spaces and garages for fire and sound control.

What Washington's energy code requires

The Washington State Energy Code sets minimums of R-49 in attics, R-21 in exterior walls (or R-13 plus R-5 continuous), R-30 in floors over crawl spaces and R-10 on crawl-space walls, and the newest code cycles push attic levels higher for new construction and additions. Most Seattle, Kirkland and Renton homes built before 1990 measure R-11 to R-19 in the attic, often with bare joists showing, so a code-level upgrade roughly halves heat loss through the ceiling. Insulation alone does not need a permit in most cities, but when it is part of a permitted remodel, addition or basement finish the inspector will check the R-values, and we handle that as part of the project. Our guide to construction permits in Washington explains when the paperwork applies.

Rebates and tax credits in 2026

Puget Sound Energy pays roughly $0.50–$1.00 per square foot for attic insulation and $0.75–$1.50 per square foot for floor and crawl-space insulation when the work meets its program specifications, and Snohomish PUD and Tacoma Public Utilities run similar programs. On top of that, the federal 25C energy-efficiency credit returns 30% of insulation and air-sealing costs up to $1,200 per year. Stacked together, incentives commonly cover $1,500–$4,000 of a Seattle insulation project, bringing a $3,200 attic job down to roughly $2,000 out of pocket. We document the installed R-values and square footage so you can file for every dollar.

Do you have to remove the old insulation?

Usually not. Dry, intact fiberglass or cellulose stays in place and gets topped up. Removal costs $1,000–$3,000 and is only necessary when the material is wet, moldy, compressed flat, or contaminated by rodents, and attics with vermiculite in homes built before 1990 must be tested and professionally abated at $3,000–$10,000 before any work begins. Wet insulation is often a symptom of a roof or gutter problem, so we check for leaks first; our roof replacement cost guide covers what that repair looks like if it turns out to be the cause.

Why insulation pairs so well with a remodel

Open walls are the cheapest moment to insulate. When we remodel a kitchen or bathroom, finish a basement, or build an addition or ADU, the framing is exposed and batts or foam go in at material cost plus a few hours of labor instead of a separate mobilization. Basement finishes in particular benefit from insulated rim joists and foam-board foundation walls, and our basement vs. addition vs. ADU guide walks through which project makes sense for your lot. Heat-pump conversions are another natural pairing: a tighter, better-insulated envelope lets the installer size a smaller, cheaper system.

What a Blue Lake insulation estimate includes

Every estimate starts with a walkthrough of the attic, crawl space and exterior walls, a measurement of the existing R-value, and a check for air leaks, moisture and ventilation problems. You receive a fixed, itemized price that separates air sealing, insulation by area, any removal and any related repairs, along with the documentation needed for PSE and federal incentives. As a licensed Washington general contractor we can also fold insulation into a larger scope under one contract, one schedule and one point of contact.

Ready to stop heating the outdoors?

Blue Lake Construction insulates and air-seals homes across Seattle, Bellevue, Kirkland, Redmond, Bothell, Sammamish, Issaquah, Renton, Mercer Island, Kent and Federal Way. Visit our home insulation service page or request a free estimate and we will tell you exactly what your attic and crawl space need before winter settles in.