Ian writes from Wakefield, Massachusetts: "I had an Owens Corning Basement Finishing System™ installed in 2006 and I would like to take the Federal energy tax credit. My reading of the tax law leads me to believe that I can take a credit of 10% of the 'cost of the insulation material,' and specifically not the cost of the entire project. However, my installer did not provide an itemized bill, and so I am unable to determine the cost basis on which to compute the tax credit. Am I misunderstanding something, or do I need to fight with my installer to obtain an itemized bill?"

Answer: You will need to get the material cost from the contractor. Ask the contractor for a line item for the insulation panels.