In order to receive your tax credit for the year 2009 you must have your windows installed by the end of the year. If they are not you still can get the credit for 2010. It is a max of 1500.00 that can be claimed in the year 2009 and 2010. Not 3000.00, but 1500.00 total. You have two years to use it and you can not double dip.