If you did not claim a qualifying tax credit in a prior year, you may be able to file an amended tax return for the year's return in which you made the improvement. However, you cannot claim it on your current tax return. For example, you cannot claim the credit for improvements made in 2009 on your 2010 taxes. For information on making an amendment, you can contact the Internal Revenue Service (www.irs.gov/contact)  or work with a tax specialist.