Credit For Energy-Saving Home Improvements
You can claim a tax credit equal to 30% of the cost of energy-saving home improvements up to a maximum of $1,500. This cap applies to both 2009 and 2010 combined, so if you claimed the maximum $1,500 in 2009, you don't get another crack at it for 2010. The credit applies to biomass fuel stoves, qualifying skylights, windows and outside doors, and high-efficiency furnaces, water heaters and central air conditioners.
For 2011, this credit goes back to pre-2009 limits (for example, $500 maximum credit for all years with no more than $200 for windows).
There's also no dollar limit on the separate credit for homeowners who install qualified residential alternative energy equipment, such as solar hot water heaters, geothermal heat pumps and wind turbines. Your credit can be 30% of the total cost (including labor) of such systems installed through 2016.