The U.S. IRS has published a practice unit on the IRC 179D Energy Efficient Commercial Buildings Deduction. The process overview of the practice unit includes the following: NOTE: This version of the Practice Unit reflects amendments made to IRC 179D by the Taxpayer Certainty and Disaster Relief Act of 2020, a part of the Consolidated Appropriations Act of 2021 (Pub. L. 116-260, December 27, 2020) (the "2020 Act") which made IRC 179D permanent for tax years beginning after December 31, 2020. This Practice Unit supersedes the December 11, 2018 and June 19, 2020 Practice Units with the same title. IRC...