How much does it cost to replace one window in King County, WA?

A single double-hung window replacement in King County costs between $340 and $1,370, with a typical price around $800. This reflects a 1.14x local adjustment over national averages due to higher Seattle-area labor rates of $34.37 per hour.

How much does a full-home window replacement cost in King County?

Replacing 10 windows in a King County home typically runs $5,700 to $17,100, with an average around $9,690. Bay or bow windows cost more, averaging $2,850 each locally.

Why are window replacement costs higher in King County than the national average?

King County's 1.14x cost adjustment is driven by local installer wages averaging $34.37 per hour, which is about 24% above the national mean of $27.75 per hour. Materials account for roughly 40% of costs and are relatively consistent nationwide, so the premium is concentrated in the labor portion.

What climate zone is King County for window energy ratings?

King County is in IECC Climate Zone 4C with a marine moisture regime. Windows installed here should meet a minimum U-factor of 0.30 and SHGC of 0.40 per 2021 energy code requirements. The DOE classifies this as the north HVAC region.

Will energy-efficient windows save money on electricity in King County?

At Washington's residential rate of $0.138 per kWh, upgrading to double-pane low-E windows can reduce glazing heat loss by 25–50%. The relatively low electricity cost means payback periods are longer than in high-rate states, but savings still accumulate over the window's 20-to-30-year lifespan.

What natural hazards should I consider when choosing replacement windows?

King County's FEMA risk score is 99.68 out of 100 (Very High). Key concerns include winter weather (94.72), ice storms (91.10), and inland flooding (99.46). Consider impact-resistant glass and water-tight installation, especially for ground-level windows.

What financing options are available for window replacement in King County?

With mortgage rates at 6.38%, home equity lines of credit are one option given King County's median home value of $811,200. Manufacturer zero-interest promotions (12–24 months) and federal energy-efficiency tax credits (up to $600 per year) can also help offset the typical $9,690 cost for a 10-window project.

REGIONAL COST GUIDE · King County, WA

How Much Does Window Replacement Cost in King County, WA?

Window replacement in King County, WA costs $340–$1,370 per window. See local labor rates, hazard factors, and financing options for 2026.

Cost range $340 – $1,370

Average $800

Updated April 12, 2026

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COST BREAKDOWN

What homeowners in King County actually pay.

Local market ranges built from regional labor, materials, and permitting data — not national averages.

Single Window Replacement (double-hung)

$340 Avg: $800 $1,370

Full Home (10 windows)

$5,700 Avg: $9,690 $17,100

Bay / Bow Window

$1,710 Avg: $2,850 $4,560

National avg $300–$1,200 (typical $700) × 1.14x local adjustment = $340–$1,370 (typical $800)

Why King County prices look like this.

King County, WA homeowners typically pay between $340 and $1,370 per window for replacement, with a full-home project of 10 windows running $5,700 to $17,100. These figures reflect a 1.14x local cost adjustment driven by Seattle-area labor rates that exceed the national average. King County's median home value of $811,200 — approximately 4.71x the national average — means window replacement represents a relatively modest investment compared to overall property value. The region's combination of wet winters, occasional ice storms, and high flood risk makes energy-efficient, well-sealed windows particularly important. Whether you are replacing a single aging double-hung or upgrading an entire home with modern bay windows, understanding local pricing helps you evaluate contractor quotes with confidence. This guide breaks down labor, hazard, climate, energy, and financing factors specific to King County so you can budget accurately for your project.

Local Labor Costs for Window Installation

Window installers in the Seattle-Tacoma-Bellevue metro area earn an average of $34.37 per hour (annual mean of $71,500), according to 2024 Bureau of Labor Statistics data for roofers and related trades (SOC 472181). This wage is approximately 24% above the national average of $27.75 per hour, which is the primary driver behind King County's 1.14x services adjustment factor. The local market employs roughly 2,500 workers in this trade category, indicating a healthy but competitive labor pool. During peak season from late spring through early fall, installer availability may tighten and lead times can stretch to several weeks. To get the best pricing, consider scheduling your project during the slower winter months when contractors are more likely to offer competitive bids. Always verify that your installer carries a Washington State contractor license and appropriate bonding before signing a contract.

Hazard Risks That Affect Window Choices in King County

King County carries a FEMA National Risk Index score of 99.68 out of 100 (Very High), which directly affects window durability requirements. The most relevant hazards for window replacement include winter weather (score 94.72, Relatively High) and ice storms (score 91.10, Relatively High), both of which can stress window seals and frames through freeze-thaw cycles. Inland flooding scores 99.46 (Very High), making water-tight window installation critical for ground-level and basement windows. Wildfire risk at 79.45 means homeowners near wooded lots should consider tempered or fire-rated glass. Wind and tornado risk at 73.16 (Relatively Moderate) may warrant impact-resistant options in exposed locations. Choosing windows rated for these specific hazards can reduce long-term maintenance costs and may qualify for insurance discounts from your carrier.

Climate Zone Considerations for King County Windows

King County falls within IECC Climate Zone 4C, characterized by a marine (C) moisture regime and classified in the DOE's north HVAC region. Zone 4 requires a minimum window U-factor of 0.30 and a Solar Heat Gain Coefficient (SHGC) of 0.40 or lower under the 2021 International Energy Conservation Code. The marine climate means windows face persistent moisture exposure from rain and fog rather than extreme cold, making vinyl and fiberglass frames popular choices over wood, which demands more maintenance in damp conditions. Triple-pane windows, while not required by code in Zone 4, can deliver meaningful energy savings given the region's long heating season. Look for ENERGY STAR certification for the Northern climate zone to ensure your replacement windows meet or exceed local performance thresholds and qualify for available rebate programs.

Energy Costs and Window Efficiency in Washington

Washington State residential electricity costs $0.138 per kWh as of January 2026, which is below the national average but still adds up over time with inefficient windows. Upgrading from single-pane to double-pane low-E windows can reduce heating energy loss through glazing by 25% to 50%, translating to measurable savings on winter heating bills in King County's long, cool wet season. For a home with 10 windows, this energy improvement can offset a meaningful portion of the replacement cost over the window's 20-to-30-year lifespan. Washington's relatively low electricity rates mean that payback periods for premium triple-pane upgrades are longer than in higher-cost energy states, so double-pane low-E often represents the best value for most homeowners. Check with your utility provider for available rebate programs, as Puget Sound Energy and Seattle City Light both periodically offer window upgrade incentives.

Financing Your Window Replacement in King County

With the current 30-year fixed mortgage rate at 6.38% as of March 26, 2026, many King County homeowners explore financing options for full-home window replacement projects. A $9,690 project (the local average for 10 windows) financed through a home equity line of credit may carry lower rates than an unsecured personal loan, especially given King County's strong median home value of $811,200 and median property taxes of $6,785 per year. The county's 4.71x home-value premium over the national average means most homeowners have significant equity available for improvement financing. Some window manufacturers and installers offer 12-to-24-month zero-interest promotional financing, which can be the most cost-effective option if you repay within the promotional period. Energy-efficient upgrades may also qualify for federal tax credits, potentially covering up to $600 per year in qualifying window costs.

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FREQUENTLY ASKED · 07

Questions buyers ask about window replacement in King County.

Short answers to the most common things we hear about local pricing, scope, and timing.

How much does it cost to replace one window in King County, WA?

A single double-hung window replacement in King County costs between $340 and $1,370, with a typical price around $800. This reflects a 1.14x local adjustment over national averages due to higher Seattle-area labor rates of $34.37 per hour.
How much does a full-home window replacement cost in King County?

Replacing 10 windows in a King County home typically runs $5,700 to $17,100, with an average around $9,690. Bay or bow windows cost more, averaging $2,850 each locally.
Why are window replacement costs higher in King County than the national average?

King County's 1.14x cost adjustment is driven by local installer wages averaging $34.37 per hour, which is about 24% above the national mean of $27.75 per hour. Materials account for roughly 40% of costs and are relatively consistent nationwide, so the premium is concentrated in the labor portion.
What climate zone is King County for window energy ratings?

King County is in IECC Climate Zone 4C with a marine moisture regime. Windows installed here should meet a minimum U-factor of 0.30 and SHGC of 0.40 per 2021 energy code requirements. The DOE classifies this as the north HVAC region.
Will energy-efficient windows save money on electricity in King County?

At Washington's residential rate of $0.138 per kWh, upgrading to double-pane low-E windows can reduce glazing heat loss by 25–50%. The relatively low electricity cost means payback periods are longer than in high-rate states, but savings still accumulate over the window's 20-to-30-year lifespan.
What natural hazards should I consider when choosing replacement windows?

King County's FEMA risk score is 99.68 out of 100 (Very High). Key concerns include winter weather (94.72), ice storms (91.10), and inland flooding (99.46). Consider impact-resistant glass and water-tight installation, especially for ground-level windows.
What financing options are available for window replacement in King County?

With mortgage rates at 6.38%, home equity lines of credit are one option given King County's median home value of $811,200. Manufacturer zero-interest promotions (12–24 months) and federal energy-efficiency tax credits (up to $600 per year) can also help offset the typical $9,690 cost for a 10-window project.

SOURCES · 08

How these numbers were built.

Cost estimates are derived from government data including the U.S. Census Bureau (ACS), Bureau of Labor Statistics (OEWS), FEMA National Risk Index, EIA energy data, IECC climate zone classifications, Federal Reserve (FRED), and HUD Fair Market Rents.