The Federal tax credit for high efficiency home improvements was amended and extended through December 31 of 2011 by the Tax Relief Act, Unemployment Insurance Reauthorization, and Job Creation Act of 2010.
On January 1 of 2011 several key points of this credit were altered from their 2010 structure. Most significantly, the limit was reduced from $1,500 to $500. The limit is on the total amount of credits a homeowner may claim from 2006 to 2011. If a homeowner installs a high efficiency ductless air conditioner or heat pump, tankless water heater or wallhung boiler, and has already claimed $500 or more in credit through this allowance, they will be unable to claim new credits for improvements made during 2011.
For more information visit http://www.dsireusa.org/incentives/incentive.cfm?Incentive_Code=US43F.