Insulated Glass Replacement & Repair

The most common sign of a failed IGU seal is condensation or fogging between the glass panes that cannot be wiped away from either side. You may also notice a cloudy or streaked appearance inside the unit, drafts near the window, a spike in heating or cooling costs, or visible mold along the window edges. If you see any of these signs, contact Portland Glass for an assessment.

Yes. In most cases, Portland Glass can replace the insulated glass unit (IGU) while leaving your existing frame intact. Replacing only the glass is typically 50–70% less expensive than a full window replacement and is the right solution when your frames are structurally sound. Our glaziers will assess your windows and confirm whether glass-only replacement is an option.

Insulated glass repair addresses issues with the seal or frame when the glass itself is still intact. Insulated glass replacement involves installing a new IGU—the full sealed unit—when the seal has failed, the glass is cracked, or condensation has developed between the panes. Portland Glass handles both and will recommend the most cost-effective solution for your windows.

With proper installation and maintenance, IGU seals typically last 20–30 years. Lifespan varies depending on climate exposure, UV radiation, and material quality. In the variable weather of Maine, New Hampshire, Massachusetts, and Vermont, regular inspection can help catch seal failures before they affect your energy bills. Portland Glass can assess your units and advise on timely replacement.

The most common fill gas is argon, which is denser than air and improves insulation by approximately 30% compared to an air-filled unit. Krypton gas offers even better thermal performance—roughly a 40% improvement—and works best in narrower gaps and colder climates. Portland Glass offers IGUs with gas-filled spacers, and our team will help you select the right option for your home.