The Internal Revenue Service has updated and added new guidance for taxpayers claiming the Energy Efficient Home Improvement Credit and the Residential Clean Energy Property Credit.

The updated includes a set of frequently asked questions and answers, superseding the . The IRS noted that the updates include substantial changes.

New sections have been added on how long a taxpayer has to claim the tax credits, guidance for condominium and co-op owners, whether taxpayers who did not previously claim the credit can file an amended return to claim it, and a series of questions on qualified manufacturers and product identification numbers. Other material has been added on how to claim the credits, what kind of records a taxpayer has to keep for claiming the credit, and for how long, and whether taxpayers can include financing costs such as interest payments in determining the amount of the credit.

The IRS states that "financing costs such as interest, as well as other miscellaneous costs such as origination fees and the cost of an extended warranty, are not eligible expenditures for purposes of the credit."