As of Dec. 17, 2010 the federal energy efficiency tax credit has been extended through 2011, but the federal government has significantly changed the credit limits and eligibility requirements.

The credit will be reduced from 30 percent to 10 percent of the energy efficiency improvement costs, and the maximum tax credit will drop from $1,500 to $500. Additionally, the $500 cap will apply to anyone who received the credit from Jan. 1, 2005 to present, which means, if you claimed $500 or more of the credit at any point since Jan. 1, 2005, you won't be eligible for the 2011 extension.

If you haven't yet received the credit or haven't fully completely used the $500 available, certain energy efficiency upgrades such as ENERGY STAR appliances, HVAC systems and more will be eligible for the credit. The credit, which you'll be able to claim on your 2011 federal tax returns, will be equal to 10 percent of the cost of installation up to $500. Special credit limits have been put on certain qualifying equipment:

Main air circulating fans – $50
High efficiency furnaces and boilers – $150
ENERGY STAR Windows – $200
Energy efficient water heaters, heat-pump water heaters and heat pumps – $300

Some of the qualifying equipment must also meet new efficiency standards. For example, boilers must now be 95 percent (or more) efficient.

EnergySavvy will update the information on the federal energy efficiency tax credit found in our rebates and tax credits directory in January 2011.