Executive summary
Key Takeaways
Section 179D
H.R. 8477 proposes removing the current termination provision.
Current cutoff
The June 30, 2026 beginning-of-construction rule remains controlling law.
Section 45L
The bill proposes extending the credit through December 31, 2032.
Legislative status
Introduced in the House and referred to committee—not enacted.
What current law says
Public Law 119–21 added a termination rule to Internal Revenue Code §179D. The deduction is not allowed for property whose construction begins after June 30, 2026. That beginning-of-construction date—not simply a building's placed-in-service date—controls the new cutoff. The IRS describes the same rule in its current guidance. Review IRS guidance
Projects that began construction on or before the cutoff may still warrant a fact-specific review. Eligibility also depends on the building, energy performance, applicable reference standard, certification, taxpayer status, and other requirements.
What H.R. 8477 proposes
H.R. 8477 would strike §179D(i), the termination subsection. Its effective-date language would treat the amendment as though included in the 2025 law that created the cutoff. As introduced, this would leave Section 179D without a scheduled expiration.
The bill would also replace Section 45L's June 30, 2026 termination date with December 31, 2032. It contains separate proposed changes for Sections 45V, 45Y, and 48E. Read the official bill text
Why early planning still matters
A pending bill does not replace current deadlines or technical requirements. Building owners, designers, architects, engineers, and design-build firms should evaluate projects under the law in effect today rather than assume a future legislative outcome.
Early review can help identify potential projects, clarify construction timing, and preserve records while they are accessible. It can also help technical and tax teams coordinate before filing decisions are made.
Planning and documentation
Depending on the project and claimant, relevant planning records may include:
- Energy modeling
- Required certifications
- Allocation letters, where applicable
- Construction documentation
- Prevailing wage and apprenticeship documentation, where applicable
- Placed-in-service records
- Tax filing and substantiation records
These are examples only. Not every item is required for every project, and additional records may be necessary.
Legislative status
The official introduced bill records an April 23, 2026 introduction and referral to the House Committee on Ways and Means. No later outcome is implied.
- IntroducedComplete
- House CommitteeCurrent
- House/Senate PassagePending
- Signed Into LawPending
Sources and review standard
Legislative details were checked against the official introduced text of H.R. 8477. The current Section 179D cutoff was checked against IRS guidance for Public Law 119–21. Last reviewed September 17, 2026.