What It Is, Why It Happens, and What It Costs to Fix Window seal failure is one of the most common defects found during Las Vegas home inspections , especially in homes built from the mid-1990s through the early 2010s. While it may start as a cosmetic issue, failed window seals can increase HVAC costs, reduce comfort, and signal aging building components . This article explains how window seal failure occurs , why it’s especially common in Las Vegas , what inspectors look for