2026 New Window Law… Are you Ready?

Written By Bo Peiffer

🏠 What Colorado’s 2026 Window Law Means for You

Dear Homeowner / Valued Customer,

Big changes are coming in Colorado building codes — especially when it comes to windows, doors, and skylights. As a local window‑ and restoration provider, we want you to be aware of what’s changing and how it can affect your next remodel or window replacement.

⚖️ What’s Changing: The New Rules

  • Starting January 1, 2026, new law under House Bill 23-1161 (and related energy‑code updates) requires that all new residential windows, doors, and skylights sold or leased in Colorado (in homes of three stories or less) meet higher energy‑efficiency standards.

  • The law enforces compliance by requiring products to meet either:

    1. The “northern climate zone” criteria under ENERGY STAR for windows, doors, and skylights; or

    2. Alternative energy‑efficiency standards established under the state’s code (§ 5 CCR 1004‑2(1.1)).

    3. In practice, this means many standard windows currently on the market may no longer qualify — especially double‑pane units lacking upgraded thermal specs.

💡 What This Means for Homeowners & Renovators

  • Better energy efficiency and lower utility bills. The requirement encourages windows with improved insulation. (i.e. lower U‑factor, better glazing, gas fills, and warm-edge spacers), which reduces heat loss and can lower heating/cooling costs in Colorado’s climate.

  • Higher standard for materials. To comply, windows will likely need upgraded glazing, better spacers, and possibly thicker frames — in other words, higher‑performance products (not the lowest-cost builder-grade windows).

  • Wider use of efficient window systems. As a window installer in the Denver metro and Front Range areas, we expect demand to increase for premium windows designed for the “northern climate zone” — especially for homes exposed to Colorado’s winters and temperature swings.

  • Code compliance becomes mandatory. For anyone selling, leasing, or installing new windows, there’s no longer optional compliance: starting 2026, windows must meet the revised standards to be legally offered or installed.

✅ What We Recommend for You

If you’re thinking about replacing windows, remodeling, or installing new ones:

  • Request ENERGY STAR–rated windows built for the Northern climate zone and double‑check U‑factor/spec sheet.

  • Ask for warm-edge spacer systems, proper gas fills, and thermally efficient glazing.

  • Work with experienced installers familiar with the 2026 code — that’s us! As a window and restoration company serving the Denver metro and Colorado Front Range, we’ll make sure your project is code compliant and optimized for performance.

https://www.coloradosos.gov/CCR/GenerateRulePdf.do?ruleVersionId=12087

Warm Regards,

RPG Windows & Restoration

Bo Peiffer