Energy efficient deduction

[Swishmik91]

We replaced all the exterior doors on our house in 2019 and did not claim the deduction on our 2019 tax return. Can we claim this cost on our 2020 return?

[Opus 17]

No, you would have to file an amended 2019 return.  The credit is 10% of the cost for the doors, not including installation, and to qualify, the doors must be rated Energy Star 6.0 or better.  

[SweetieJean]

As @Opus 17 indicated, it's a tax credit, not a deduction against income.  However, the Federal credit is limited to $500 overall.

Energy Incentives for Individuals: Residential Property Updated Questions and Answers | Internal Rev...