Section 45L: The Complete Guide to the Energy Efficient Home Credit
The IRA dramatically expanded Section 45L, raising the credit from $2,000 to up to $5,000 per dwelling unit and extending it through 2032. For residential developers and homebuilders, 45L is now one of the most straightforward federal credits available — no complex partnership structure required.
What Is Section 45L?
Section 45L of the Internal Revenue Code provides a tax credit to contractors who build energy-efficient residential dwelling units. Originally enacted in 2005, the IRA substantially revamped the program starting January 1, 2023: credit amounts more than doubled, the certification standards were updated to align with current ENERGY STAR and DOE Zero Energy Ready programs, and the program was extended through 2032.
Unlike most clean energy credits, 45L is specifically designed for residential construction — single-family homes, multifamily buildings, condominiums, and manufactured homes. The credit is claimed by the developer/builder, not by the homebuyer.
Credit Amounts by Dwelling Type
| Dwelling Type | ENERGY STAR | Zero Energy Ready |
|---|---|---|
| Single-family / Manufactured home | $2,500/unit | $5,000/unit |
| Multifamily (3+ stories) | $500/unit | $1,000/unit |
| Multifamily + Prevailing Wage | $2,500/unit | $5,000/unit |
Who Qualifies
The credit is claimed by the eligible contractor — defined as any person who constructed the qualified new energy efficient home and owns it during construction for sale or lease. This includes:
- Production homebuilders (single-family subdivisions)
- Multifamily developers who build and rent apartments
- Condominium developers who build and sell units
- Manufactured housing manufacturers
Important: The homebuyer or tenant cannot claim 45L. The credit belongs to whoever built and originally owned the dwelling unit. Custom home builders who build on a client's land and immediately transfer title must carefully analyze whether they meet the ownership requirement.
Certification Requirements
Each dwelling unit must be certified by a qualified third-party certifier. The certification process depends on which standard the unit is designed to meet:
ENERGY STAR Certification
- A RESNET-certified Home Energy Rater (HERS rater) or EPA-recognized verifier conducts field verification
- The home must achieve the current ENERGY STAR Single Family New Homes specification (Version 3.2 or later as of 2026)
- For multifamily: ENERGY STAR Multifamily New Construction program certification
- The certifier issues a signed Certificate of Qualifying New Energy Efficient Home
DOE Zero Energy Ready Home Certification
- RESNET-certified rater certifies the home meets DOE ZERH program requirements
- ZERH requires significantly higher performance than ENERGY STAR — typically a HERS Index 45 or below plus solar-ready infrastructure
- The home must be ENERGY STAR certified as a prerequisite for ZERH
- Certification documentation and HERS report must be retained by the taxpayer
How to Claim the Credit
The Section 45L credit is reported on Form 8908 (Energy Efficient Home Credit) and flows through Form 3800 (General Business Credit). The credit is claimed in the tax year the qualifying unit is first sold or leased to a person for use as a residence.
For large developers selling hundreds of units per year, the cumulative credit can be substantial. A builder selling 200 ZERH-certified single-family homes in a tax year would generate $1,000,000 in Section 45L credits ($5,000 × 200 units).
Real Example: 100-Unit Multifamily Development
Scenario: 100-unit apartment building, ZERH-certified, prevailing wage compliant
This $500,000 credit can be stacked with ITC for rooftop solar on the building, and with state-level housing tax credits if applicable — dramatically improving project returns.
Stacking with Other Credits
Section 45L stacks cleanly with several other federal credits:
- ITC (§48): If the development includes a solar array allocated to the building owner (common in multifamily), the ITC applies to the solar installation cost independently of the 45L credit.
- 179D: For mixed-use buildings with commercial ground-floor space, the 179D deduction applies to the commercial portion's energy-efficient improvements, while 45L covers the residential units.
- LIHTC (§42): Affordable housing developers can stack 45L with Low-Income Housing Tax Credits. The 45L credit does not reduce the eligible basis for LIHTC purposes.
Frequently Asked Questions
Who can claim the Section 45L credit?
Section 45L is claimed by the "eligible contractor" — the person who constructs the dwelling unit and owns it for sale or lease. This is typically the developer or builder, not the homebuyer or tenant. For rental properties, the landlord/developer who builds and rents out the units can claim the credit in the tax year the unit is first sold or leased.
What are the 45L credit amounts for 2026?
For single-family homes: $2,500 per unit for homes meeting ENERGY STAR Single Family New Homes standard; $5,000 per unit for homes meeting the DOE Zero Energy Ready Home standard. For multifamily buildings (3+ stories): $500 per unit for ENERGY STAR Multifamily New Construction standard; $1,000 per unit for DOE Zero Energy Ready Home standard. If the multifamily project also satisfies prevailing wage requirements, the per-unit rates increase to $2,500 and $5,000 respectively.
What certification is required for Section 45L?
The dwelling unit must be certified by a qualified certifier as meeting the applicable energy efficiency standard: (1) For ENERGY STAR certification: a RESNET-certified rater or ENERGY STAR verifier conducts a field verification and HERS rating of the home; (2) For Zero Energy Ready Home certification: a RESNET-certified rater certifies the home meets the DOE ZERH program requirements. The certifier provides a certificate that the taxpayer retains to support the credit claim.
Can a multifamily developer claim both 45L and other IRA credits?
Yes. A multifamily developer can claim 45L per dwelling unit AND stack the ITC for solar panels on the building (if separately installed and allocated to the building owner). For mixed-use buildings with commercial space, the 179D energy efficient commercial building deduction may apply to the commercial portion. The credits do not offset each other as they apply to different aspects of the project.
When is the Section 45L credit claimed?
The credit is claimed in the tax year the qualifying dwelling unit is first sold or leased to a person for use as a residence. The credit is reported on Form 8908 (Energy Efficient Home Credit) and flows through Form 3800 (General Business Credit). The $2,500 ENERGY STAR and $5,000 ZERH rates apply to homes where construction begins after December 31, 2022.
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