Certain energy efficient products purchased during 2012 are eligible for a federal tax credit. You can receive a tax credit for 10 percent of the cost up to $500, or a specific amount from $50-$300 for specific product categories to include: 

A different set of product categories are eligible for a tax credit of 30 percent of the cost with no upper limit until December 31, 2016. These can be used on new or existing homes for the following product categories: 

To receive these tax credits, you will need to submit the 5695 form with your 2012 taxes. More information on these tax credits is available on the U.S. Department of Energy website.