The §45L Builder Credit
"Build a 50-unit apartment complex to Zero Energy Ready specs and the IRS hands you a $250,000 check. Per unit, not per project. Most developers don't even know it exists."
The 60-second pitch
The New Energy-Efficient Home Credit (§45L) rewards builders and developers — not buyers — for constructing homes that meet ENERGY STAR or DOE Zero Energy Ready Home (ZERH) standards. Post-IRA, the credit is:
- Single-family / manufactured homes: $2,500 for ENERGY STAR, $5,000 for DOE ZERH
- Multifamily (4+ units per building, low-rise, mid-rise, high-rise): $500–$2,500 per unit for ENERGY STAR / $1,000–$5,000 per unit for DOE ZERH, with the higher rate requiring prevailing wage (PWA) compliance.
This is a per-unit credit, not per-project. A developer who builds a 50-unit apartment complex meeting DOE ZERH at the PWA rate earns 50 × $5,000 = $250,000 of credit. Multiply that across a stabilized 200-unit portfolio and §45L can rival the developer's net operating margin in year one.
The OBBBA reality. The One Big Beautiful Bill Act terminates §45L for homes acquired (sold or leased to an unrelated person) after June 30, 2026. "Acquired" means the home is first sold or leased — not when construction starts. Units delivered and leased by that date qualify; units leased July 1, 2026 or later do not.
For active developers, this creates a 12-month window: finish, certify, and sell or lease your in-progress projects on or before June 30, 2026. After that, §45L is dead for new acquisitions.
Real-world example
The setup. Maplewood is finishing Riverbridge Lofts, a 64-unit mid-rise apartment building completed in spring 2026. Construction kicked off in summer 2024. The MEP engineer specified DOE Zero Energy Ready Home features — superinsulation (R-30 walls, R-49 attic), tight envelope (1.5 ACH50), heat pump water heating, ERV ventilation, all-electric panel, solar-ready conduit.
PWA compliance. Maplewood paid Davis-Bacon prevailing wages on all union trades and met the 12.5% apprenticeship-hours requirement. Certified payroll is on file with the GC's records.
Certification. A third-party HERS rater (RESNET-certified) inspects every unit at pre-drywall and final stages, performs blower-door testing, and certifies each unit meets DOE ZERH requirements. Cost: ~$650/unit = $41,600 total certification fee.
The credit. 64 units × $5,000 (DOE ZERH multifamily with PWA) = $320,000 federal credit. The building is placed in service June 12, 2026 (10 units leased that month, 38 leased July–September) — only the 10 units acquired (first leased) on or before June 30, 2026 qualify post-OBBBA. 10 × $5,000 = $50,000 of credit; the remaining 54 units are timed too late.
Hard lesson. If Maplewood had pushed the leasing window 2 months earlier — pre-leasing in April for May/June occupancy — they would have captured the full $320K. The OBBBA cliff isn't about when the unit is built; it's about when it's first sold or leased.
The step-by-step checklist
- Decide the certification target on day one. ENERGY STAR (cheaper to hit, $2,500/single-family or $500-$2,500/multifamily unit) or DOE Zero Energy Ready Home ($5K/$1K-$5K). Design the building to the target, not vice versa.
- Engage a RESNET-certified HERS rater early. They inspect at pre-drywall and after final, perform blower-door tests, and issue the certification needed for the credit. Typical fee: $400–$800/unit.
- Plan PWA compliance for multifamily. Without prevailing wage + apprenticeship, multifamily credits collapse to $500/unit (ENERGY STAR) or $1,000/unit (ZERH). With PWA, they jump to $2,500 and $5,000.
- Define "acquisition" carefully. Sale (closed) or lease (first occupant takes possession) on or before June 30, 2026. Pre-leases that don't deliver units by that date may not count.
- Front-load construction and leasing. Post-OBBBA, every unit leased after June 30, 2026 forfeits §45L. Push leasing into Q2 2026.
- Sell single-family on or before June 30, 2026. A spec home built in 2025 that doesn't close until July 2026 = no credit. Move quickly.
- Maintain certification documentation per unit. HERS rating report, blower-door results, equipment cut sheets, envelope details. The IRS audits via the rater.
- For PWA: certified payroll + apprentice logs. Same Davis-Bacon framework as §179D and §30C. Required by trade for all on-site labor.
- Claim on Form 8908. Filed by the eligible contractor (the person who built and sold/leased the home) — typically the developer or general contractor.
- Reduce basis by the credit (§50(c)) only if claimed as part of the §38 general business credit. Tax-credit basis adjustment applies; consult your tax professional.
- Carry-forward unused credits. §45L is part of the general business credit — can carry back 1 year, forward 20 years.
- Don't double-dip with §179D. Multifamily 4+ stories can qualify for §179D (designer assignment) or §45L (per-unit credit) but generally not both on the same expenditure stream. Model both, pick the better one.
IRS code & authority
- §45L New Energy-Efficient Home Credit — $2,500/$5,000 per single-family, $500-$2,500 / $1,000-$5,000 per multifamily unit. OBBBA termination: credit disallowed for homes acquired after June 30, 2026.
- §45L(c) Definition of "eligible contractor" — the person who constructed the home and sold or leased it to an unrelated person for use as a residence.
- §45L(d) ENERGY STAR and Zero Energy Ready Home certification requirements.
- §45L(g) Prevailing wage requirement for multifamily PWA-rate credit.
- §38 General business credit — §45L is a component.
- §39 Carry-back / carry-forward rules.
- Form 8908 Energy Efficient Home Credit — filed by the eligible contractor.
- Notice 2023-65 Updated certification process and HERS rater requirements post-IRA.
- DOE Zero Energy Ready Home Program v1 single-family and v2 multifamily certification standards.
- ENERGY STAR Single-Family Home v3.1 / v3.2 and ENERGY STAR Multifamily New Construction v1 certification standards.
- IRS Fact Sheet FS-2025-19 OBBBA modifications including §45L acquisition cutoff of June 30, 2026.
Audit risk flags
- Missing or thin HERS certification. The IRS asks for the rater's report by unit. A blanket project-level cert is not enough. Defense: Require unit-level HERS reports as a deliverable from the rater.
- "Acquisition" date interpreted as construction-complete date. The cutoff is sale or first lease, not certificate-of-occupancy. Defense: Track lease commencement dates in a leasing pipeline tied to the credit claim.
- PWA shortfall on multifamily. Claiming the $5,000/unit ZERH rate without certified payroll. Defense: Make PWA a contract requirement on the GC; collect monthly certified payroll; document apprentice hours.
- Eligible contractor mis-identified. §45L only applies to the person who built the home and sold/leased it. A passive owner who hired a contractor doesn't qualify (the contractor might). Defense: Match the credit-claimant to the construction agreements.
- Manufactured homes treated as single-family. §45L has specific rules for manufactured homes — generally allows the same $2,500/$5,000 amounts but with HUD code conformance. Defense: Confirm HUD certification + ENERGY STAR/ZERH compliance.
- Same expenditure claimed under §179D and §45L. Layered credits on the same envelope cost. Defense: Run both calculations, claim the higher one, document the election.
- Tax-exempt entity claiming the credit directly. Schools and government developers can't claim §45L directly. Direct pay (§6417) is unavailable for §45L. Defense: Structure as a taxable joint venture or accept that §45L doesn't fit.
When NOT to do this
- Your project won't deliver units (sold or leased) by June 30, 2026. Post-cutoff acquisitions earn $0 §45L. Don't pay for HERS certification if you can't hit the date.
- You're building to standard code, not ENERGY STAR or ZERH. Without certification, no credit. The premium cost of building to ENERGY STAR is typically 1-3% of unit cost — make sure §45L recovers more than that.
- You're remodeling existing homes. §45L is new construction only (substantial reconstruction can qualify but the rules are stricter).
- You're a passive investor in a developer's project. The credit is the eligible contractor's, not yours.
- You don't have tax liability and you're not a multifamily REIT structured to pass credits. §45L is non-refundable to the contractor; without taxable income, the credit carries forward but creates a working-capital drag.
- The site can't realistically pay prevailing wages for multifamily. Without PWA, the credit drops 80% and may not justify the certification fees.
Map every unit to its §45L credit in PilePilot
For multifamily developers and home builders: PilePilot's Books agent tracks unit-level HERS certifications, ties acquisition dates (lease/sale) to the §45L credit, and flags any unit at risk of falling past the OBBBA June 30, 2026 cliff. Don't lose $5,000/unit to a timing mistake.
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Disclaimer. This page is educational and not tax advice. §45L has specific certification, acquisition-date, PWA, and eligible-contractor rules — and a post-OBBBA hard cutoff of June 30, 2026 for acquisitions. Before claiming, work with a qualified tax professional and a RESNET-certified HERS rater. All dollar examples are illustrative.