If you have filed the 2017 tax return you will have to amend the return to add the credit. See this TurboTax support FAQ for amending a 2017 tax return originally completed and filed using TurboTax (online or desktop) - https://ttlc.intuit.com/questions/4252298-how-do-i-amend-a-2017-return-in-turbotax
To enter Home Energy Credits -
- Click on Federal Taxes (Personal using Home and Business)
- Click on Deductions and Credit
- Click on I'll choose what I work on (if shown)
- Under Your Home
- On Home Energy Credits, click the start or update button
Or enter home energy improvement in the Search box located in the upper right of the program screen. Click on Jump to home energy improvement
