The tax credit is slated to go UP to 30% IF the Build Back Better act passes. The bad news, is that it moves from Section 25D, back to 25C, which means it will remain a tax credit, and not be reimbursable, like solar panels will be under 25D. Its all up to Senator Joe Manchin at this point, and looking unlikely that the BBB Act will be voted on in 2021. So, if it passes in early or mid 2022, the 30% rate would likely take effect Jan. 1, 2023. And it will still cover installation, venting, floor protection etc. - anything that is essential to a safe installation.