On June 1, the U.S. Energy Tax Credit reverted to the original window and door criteria established in February as part of the American Recovery and Reinvestment Act of 2009.  In April, the government had announced that it would allow any ENERGY STAR qualified windows or exterior doors purchased between January 1 and May 31 of 2009 to be eligible for the $1,500 tax credit.  The main criteria now is that windows and doors must have a U-value (U-factor) of 0.30 or less and a Solar Heat Gain Coefficient (SHGC) of 0.30 or less. Note: Not all ENERGY STAR qualified windows and doors meet these criteria.

So if you purchased ENERGY STAR qualified windows or doors between January 1 and May 31 of 2009 -- regardless of their U-value and SHGC ratings --  you are eligible for a tax credit up to $1,500. If you purchase them from June 1, 2009 to December 31, 2010, you are eligible for the same tax credit as long as they meet the 0.30/0.30 criteria. There are other criteria, by the way. See ENERGY STAR's web page www.energystar.gov/index.cfm?c=products.pr_tax_credits for more details.

For windows and doors qualifying from January 1, 2009 to May 31, 2009, you can use (for tax purposes) the ENERGY STAR labels that came with them. You can also use applicable Manufacturer's Certification Statements for this period. 

From June 1 to December 31, 2010, you cannot use the ENERGY STAR labels for tax purposes; you can only use applicable Manufacturer’s Certification Statements from the manufacturer.

Gorell's statements for both time periods are available on its web site, http://www.gorell.com/pages/energy_tax_incentive_act.htm