45L Energy Efficient Home Credit
Up to $5,000 per new or renovated dwelling unit.
The §45L tax credit rewards builders, developers, and owners of residential buildings — including single-family homes, townhomes, and multifamily — that meet modern energy efficiency standards. It’s a dollar-for-dollar federal credit, not a deduction, and it can be claimed on units placed in service over the past several years.
How it works
45L applies to new construction and substantial renovations of dwelling units completed under an energy-efficient building program. Qualifying units must meet specific envelope, HVAC, water heating, and lighting performance standards, often demonstrated with a RESNET or qualified energy-modeling analysis.
For single-family and manufactured homes under 3.5 stories, the credit is up to $2,500 per unit under the applicable ENERGY STAR program, rising to $5,000 per unit for units certified as DOE Zero Energy Ready. Multifamily units start at $500 per unit ($1,000 Zero Energy Ready), but jump to the full $2,500 / $5,000 per unit when the project satisfies prevailing wage and apprenticeship requirements.
The credit is available for up to three prior open tax years, and it often stacks with other incentives like 179D, solar ITC, and local utility rebates. Because it is a credit, it directly reduces the tax you owe — making it one of the most efficient tax tools for residential developers.
You may qualify if
- You built or substantially renovated residential units
- The units are placed in service after 2021 and meet energy standards
- You have an energy modeler or HERS rater available
- You have taxable income to absorb the credit
What the engagement looks like
01
Fit check
Intake covers unit count, building type, placed-in-service dates, and current energy certifications.
02
Modeling
A qualified energy modeler or HERS rater evaluates each unit against the 45L standards.
03
Certification
Documentation is assembled and submitted to support the §45L credit claim.
04
Claim
Your CPA files the credit with your return — often for the current year and up to three open prior years.
Case study
Midwest multifamily developer
Apartment construction · Midwest
Situation
A developer placed in service an 80-unit, four-story garden-style apartment community in 2024. The project was already energy-efficient but the developer had never filed for §45L credits, leaving an estimated $200,000 in federal credits on the table.
Approach
The specialist reviewed construction docs, engaged a qualified energy modeler, and certified that all units met the §45L energy-efficiency criteria. The certification package was prepared for both the current-year filing and an amended prior-year return.
Result
Claimed the full $2,500-per-unit credit, generating $200,000 in federal tax credits. The study fee was 25% of the identified credit, and the net benefit covered the developer’s year-end tax liability outright.
Qualifying units
80
Federal credit
$200,000
Study fee (25% of credit)
$50,000
Net benefit to developer
$150,000
Illustrative example based on typical engagement outcomes. Actual results depend on your specific facts.
Common questions
Can I claim 45L on units already sold?
Yes, the eligible taxpayer is generally the person who constructed the unit and owned it when it was placed in service. For-sale homes, rental apartments, and affordable units can all qualify if the ownership and certification tests are met.
How far back can I claim?
Federal credits can typically be claimed on the three prior open tax years. If your units were placed in service during that window, you can often file an amended return and claim the credit now.
Does 45L stack with 179D or solar incentives?
Often yes. A single project can sometimes claim both 45L on the residential units and 179D on the commercial portions, plus the solar ITC and local rebates. The specialist coordinates the energy modeling to maximize the combined benefit.
Ready to see if this fits?
Short intake, no cost, matched with a specialist within days.