UPDATED June 11, 2009
The Energy Policy Act of 2005 first established the energy efficiency tax credits that were effective in 2006 & 2007. The majority of these tax credits were for 10% of the cost, up to $500. On October 3, 2008 former President Bush signed the Emergency Economic Stabilization Act of 2008 (also known as the "Bailout Bill") to put many of the tax credits back in place for 2009, and increased the credit to 30%, up to $1,500. On February 17, 2009 President Obama signed into law the American Recovery and Reinvestment Act of 2009 (also known as the "Stimulus Bill") which among other changes extended the tax credits to 2010.