tems purchased from now until the end of 2010 are eligible, but you might want to invest in some Energy Star rated improvements sooner than later. Save valuable dollars on your heating and air-conditioning bills!
The federal tax credit is for eligible product installations starting January 1, 2009 through December 31, 2010 designed to give you back 30% of what you spend on the qualifying products, not including installation, up to $1500. Since installation is not included, make sure you get an itemized list from your contractor/installer, as this will make filing for the credit far easier.
Every ENERGY STAR qualified window, door, and skylight is independently certified to perform at levels that meet or exceed energy efficiency guidelines set by the U.S. Department of Energy. According to the Energy Star website:
"Windows, doors, and skylights purchased on or after June 1, 2009 must have U-factor and Solar Heat Gain Coefficient (SHGC) ratings of 0.30 or less. These ratings must be certified by the National Fenestration Rating Council (NFRC) . NFRC is the only federally recognized organization for determining the energy performance of windows, doors and skylights."

But why stop at .30? The Challenger Window from Global Home Improvement has a rating U-factor and Solar Heat Gain Coefficient (SHGC) ratings of 0.19 and 0.24 respectively.
Also did you know Reflective Metal Roofing is eligible for the ENERGY STAR Tax Credit?