The tax credit is $200 for windows and skylights and $500 for exterior doors. The maximum credit for all taxable years for qualifying products is $500 – no more than $200 of the credit can be attributable to expenses for windows and skylights.

Ten percent of the purchase price up to the cap listed above (not including labor or materials for installation).

The tax credit begins January 1, 2011 and expires December 31, 2011. Purchasers of qualifying windows, skylights, and exterior doors must have them installed in their principle residence by December 31, 2011.

The 2011 tax incentives revert to the 2005-2008 levels: 10% of the cost installing efficient windows. Anyone who has taken advantage of the 2006 - 2010 programs cannot apply for incentives that exceed the cap. Example: if a consumer claimed $500 in 2006 for a qualifying exterior door, the tax credit is exhausted; if only $300 was claimed in 2009, $200 can still be claimed- for a total of $500.

Visit http://www.energystar.gov/index.cfm?c=home.index. The IRS will issue additional specific guidance soon. Check http://www.irs.gov for updated information.