Our expertise · Section 179D Studies

Section 179D for Building Owners

Connect your building's efficient systems to a deduction your tax team can support.

You own a taxable commercial or multifamily building, and its HVAC, lighting, hot-water or envelope systems were built or upgraded to perform. Section 179D, the energy-efficient commercial buildings deduction, may reward that work, but a deduction lives or dies on facts: who owns the property, when construction began, when the systems were placed in service and what the energy analysis actually shows. Green Summit evaluates 179D opportunities for taxable owners using the building systems, project dates and supporting records. We coordinate the engineering analysis and the required certification with your tax advisors, so the conversation is grounded in the property rather than in a headline deduction.

Licensed engineering firm
In-house CPAs
179D experience since 2007
Audit-ready documentation

Who this is for

Taxable owners of commercial, industrial and qualifying multifamily buildings, whether developers, investors, operators or owner-occupiers, and the accounting firms that advise them.

Accounting & Advisory Firms Affordable Housing & Housing Authorities Building Owners, Investors & Operators Manufacturers & Technology Companies Real Estate Developers

What we do

Screen eligibility. We review ownership, construction-start and placed-in-service information, prior work on the building and the systems within scope. Dates come first.
Evaluate the engineering. We assess the lighting, HVAC, hot-water and envelope information and develop the energy analysis the claim requires.
Inspect and certify. We plan the necessary inspections, verify the installed conditions that matter and prepare the certification records.
Coordinate with your advisor. We organize the calculation, the assumptions and the source records for your tax team, and we answer their questions.

Our process

Review the facts. We collect building, cost, system and project-date information.
Define the study. We confirm the technical pathway that applies and any remaining eligibility question, and we tell you plainly if the answer is no.
Model and verify. We perform the analysis and the field work, and we resolve discrepancies between the drawings and the building as built.
Deliver substantiation. We review the results with you and your designated tax advisors.

Benefits

An informed go/no-go decision before you commit to a full study.
Traceable support connecting the study to the actual building: energy analysis, site inspection and a licensed engineer's certification.
Coordinated engineering and tax-advisor review, with the calculation, assumptions and source records in one package your CPA can use.

Why Green Summit

Green Summit is one of a select few firms nationwide that combine a licensed engineering firm with in-house CPAs, so the team that models your building is the team that inspects and certifies it. Our work connects energy models, field evidence and the financial question you are actually evaluating. Our leadership's 179D experience dates to 2007, professional experience that predates the firm's founding in 2014, and it shows in how we screen: property facts and dates first, deduction second.

As a consulting partner delivering end-to-end compliance solutions, we can coordinate adjacent fixed-asset or incentive work, such as cost segregation or a disposition study, without treating those separate benefits as automatic or interchangeable. Every study is built to be audit-ready from day one: engineered substantiation, not estimates.

What changed in 2026

Under federal legislation enacted in July 2025 (Public Law 119-21), Section 179D winds down for property whose construction begins after June 30, 2026. Property that began construction on or before that date falls under the statutory transition rule, so existing and transition projects require date-specific review; this is not a blanket completion deadline. We screen every project against its construction-start and placed-in-service records before anyone counts on a deduction.

179D is a tax deduction, not a credit or a cash payment. The deduction is not the same as cash received: usability and final tax treatment depend on the taxpayer and current law. If your firm designed a building for a government, Tribal or nonprofit owner, the designer route applies instead. Designer eligibility depends on responsibility for creating the technical specifications for qualifying installed property, not the job title alone, and every allocation requires the owner's separate written authorization.

Frequently asked questions

What is Section 179D for building owners?

Section 179D is a federal deduction for energy-efficient commercial building property: qualifying interior lighting, HVAC and hot-water systems and the building envelope, in commercial buildings including qualifying multifamily buildings. A taxable owner claims it on its own building, supported by an energy analysis, a site inspection and an engineer's certification. Your tax advisor determines the return position.

What should an owner send for initial screening?

Ownership information, building use and area, the installed systems, construction and placed-in-service dates, prior studies and the plans you have. We identify evidence gaps before anyone commits to detailed analysis.

What does the June 30, 2026 cutoff mean?

Property whose construction begins after that date is outside the statutory transition rule. An earlier start qualifies only when project records and current tax guidance support it, which is why date screening is our first step.

Can a retrofit be considered?

Potentially. We evaluate the property and the pathway, including the relevant dates and performance requirements. We never assume a planned equipment replacement is eligible simply because it is efficient.

Does Green Summit file the deduction?

No. We provide the technical analysis and the certification. Your tax advisor determines and files the tax position, including basis, prior claims and other return-level matters.

Can the study be coordinated with an energy audit?

Yes. Site information and modeling inputs often overlap, but an audit recommendation and a 179D certification are different deliverables. When you need both, we define both.

Let's talk about your building.

Tell us the building, where it is, what was built or upgraded and when construction started.

Program and technical references

IRS: Energy Efficient Commercial Buildings Deduction

Program information reviewed September 22, 2026. Current applicability, qualifications and program terms are confirmed for each engagement.

Or call 321-273-2200 · inquiry@greensummit.com