Currently, taxpayers may be able to claim two tax credits for residential energy efficiency: one is scheduled to expire at the end of 2011, whereas the other is scheduled to expire at the end of 2016. The nonbusiness energy property tax credit (Internal Revenue Code (IRC) 25C) currently provides homeowners with a tax credit for investments in certain high-efficiency heating, cooling, and water-heating appliances, as well as tax credits for energy-efficient windows and doors. For installations made during 2011, the credit rate was 10%, with a maximum credit amount of $500. The credit available...