The Dept of Energy web site:
http://www.dsireusa.org/incentives/incentive.cfm?Incentive_Code=US43F&re=1&ee=1
Incentive Type: Personal Tax Credit
State: Federal
Eligible Efficiency Technologies: Water Heaters, Furnaces, Boilers, Heat pumps, Air conditioners, Building Insulation, Windows, Doors, Roofs, Circulating fans used in a qualifying furnace
Eligible Renewable/Other Technologies: Biomass, Stoves that use qualified biomass fuel
Applicable Sectors: Residential
Amount: 30%
Maximum Incentive: Aggregate amount of credit for all technologies placed in service in 2009 and 2010 combined is limited to $1,500
Equipment/Installation Requirements: Equipment must be new and in compliance with all applicable performance and safety standards as described in tax code
Authority 1: 26 USC § 25C
Date Enacted: 8/8/2005 (subsequently amended)
Date Effective: 1/1/2006
Expiration Date: 12/31/2010
Summary:
The federal tax credit for energy-efficient home improvements was established by the Energy Policy Act of 2005. After expiring December 31, 2007, the credit was extended and expanded by The Energy Improvement and Extension Act of 2008 (H.R. 1424: Div. B, Sec. 302) and The American Recovery and Reinvestment Act of 2009 (H.R. 1: Div. B, Sec. 1121). The credit now applies to eligible equipment purchased between January 1, 2009, and December 31, 2010. In addition to extending the credit, H.R. 1424 and H.R. 1 strengthened the efficiency requirements for most equipment, extended the credit to stoves that use biomass fuel and asphalt roofs with appropriate cooling granules; raised the cap for the credit; and redesigned the way the credit is calculated.
The above requirement says must be new, and placed in service.