Should You Upgrade from Single Pane to Double Pane Windows?

It depends on the frame type. Many older wood-frame and aluminum-frame windows can be retrofitted with a new insulated glass unit if the frame sash is deep enough to accommodate the thicker double-pane unit — typically 5/8 inch to 7/8 inch versus the 3/16 inch of a single pane. We measure your existing sash on the assessment visit to confirm whether retrofit is possible. In most cases it is, especially for casement and double-hung windows with standard-depth sashes. When retrofit is not feasible, we discuss full sash replacement versus frame replacement as the next options.

The DMV region has a mixed climate — hot and humid summers, cold winters — which means your windows are working against you in both directions. A single-pane window has an R-value of roughly 1. A double-pane Low-E window with argon gas reaches R-3 to R-4. In practice, homes in the DC, Maryland, and Virginia area with single-pane windows typically see heating and cooling cost reductions of 20 to 35 percent after upgrading to insulated Low-E glass, depending on the number of windows, window-to-wall ratio, and existing insulation. We provide a realistic estimate during your assessment.

Yes. Upgrading to ENERGY STAR certified insulated glass qualifies for the federal 25C residential energy efficiency tax credit, currently worth up to 30 percent of the project cost (with annual limits). Maryland, Virginia, and DC all also have utility rebate programs through Pepco, BGE, Dominion, and Washington Gas that may apply depending on your utility provider and the specific glass specification. We provide the product data sheets you need to claim these credits during your free estimate.