The federal income tax credit for energy-efficient replacement glass windows is now 30 percent of product cost up to $1,500 per household, an increase from $500 two years ago. Unlike tax credits for energy-efficient windows and doors in prior years, the criteria is stricter than the government´s ENERGY STAR rating program.
Look for the manufacturer´s labels on the glass window product packaging and be sure to save them for documentation. The manufacturer´s labels should show that the qualifying replacement glass windows meet or exceed U-factor and Solar Heat Gain Coefficient (SHGC) ratings, also called the criteria. In other words, the U-factor rating must be .30 or less and the SHGC must be .30 or less.
The most energy-efficient replacement windows on the market are triple-pane replacement windows with argon gas insulation (commonly called Insulated Glass Units or IGUs). These windows are eligible for the tax credits and will reduce your energy costs the most. Single-pane replacement windows are not eligible for the energy-efficient tax credit because glass by itself is not an insulator.
To receive the tax credit, you will have to submit an IRS Form 5695 accompanied by a receipt and all the window manufacturer labels and stickers.