solarguyben, the credit for qualified solar electric property is not to be included on Form 8936 line 21. Line 21 is to include only the residential energy credit from Form 5695 Part II (insulation, doors, roof and windows) line 30. The credit for qualified solar electric property costs is calculated on Form 8936 Part I, not Part II. See the instructions for Form 8936 line 21: https://www.irs.gov/pub/irs-pdf/i8936.pdf
