Business Tax Strategy · 179D
Who can claim
the 179D deduction?
The owner of the building, in the ordinary case. But a large share of the buildings with the best energy work, schools, hospitals, municipal buildings and universities, are owned by groups that pay no income tax and cannot use a deduction. For those, the code lets the owner hand the deduction to the designer. That allocation is the part most architects, engineers and design build firms have never asked for.
Quick answer
- The owner of a commercial building that had qualifying energy efficient work done: lighting, heating and cooling, hot water, or the building envelope.
- For a building owned by a government, a school, a hospital, a church or another tax exempt group, the owner has no tax bill to use it against, so the deduction can be allocated to the designer.
- The designer means the architect, engineer, or design build contractor responsible for the energy efficient design. They claim the deduction on their own return.
- Since 2023 the allocation rule covers every tax exempt owner, not only governments, and tribal governments and Alaska Native corporations as well.
- Whoever claims it, a licensed engineer or contractor in the building's jurisdiction has to certify the energy savings first.
- The building must be in the United States and within the scope of the reference standard. Larger multifamily buildings can qualify. Single family homes cannot.
Three ways to be the one who claims it
You own the building
A commercial building, new or improved, with certified energy efficient lighting, HVAC and hot water, or envelope work. You claim the deduction on the return for the year the property was placed in service.
You designed it for a tax exempt owner
Governments, schools, hospitals, churches, and since 2023 every other tax exempt entity, can allocate the deduction to the architect, engineer or design build contractor. You request the allocation in writing from the owner.
You are a tenant who paid for the work
A tenant that paid for and owns qualifying improvements in leased space can be the one who claims the deduction for that property.
What has to be true first
The building is in the United States and within the scope of the reference standard, which covers commercial buildings and multifamily buildings of four stories or more. The work touched at least one of the three systems: interior lighting, heating, cooling, ventilation and hot water, or the building envelope. And a qualified individual, a licensed engineer or contractor in the building's jurisdiction, modeled the energy savings with approved software and signed a certification. Without the certification there is no deduction, whoever owns the building.
The allocation, step by step
The designer identifies the projects. The owner signs an allocation letter naming the designer and the amount. The certification is completed. The designer claims the deduction on its own return for the year the building was placed in service. The owner's cooperation is easier to get while the relationship is fresh, which is why it pays to ask before the project closes out, not years later. How much is at stake is on how much 179D is worth per square foot.
Who cannot claim it
Owners of single family homes and small residential buildings, which fall outside the standard. A contractor that installed someone else's design. And, under the July 2025 tax law, anyone whose building's construction begins after June 30, 2026. The start date of the project is now the first question.
Frequently asked questions
Who can claim the 179D deduction?
The building owner, for a commercial building with certified energy efficient improvements. When the owner is a government or tax exempt entity, the deduction can be allocated to the designer, the architect, engineer, or design build contractor, who claims it instead.
What is the 179D designer allocation?
A written allocation from a tax exempt building owner giving the deduction to the person who designed the energy efficient property. The owner has no tax to offset, so the code lets the designer use it. It has to be requested from the owner and documented.
Can a contractor claim 179D?
A design build contractor can, when it was responsible for the design and the building is owned by a government or tax exempt entity that allocates the deduction. A contractor that only installed what someone else designed generally cannot.
What is a 179D certification?
A signed statement from a qualified individual, a licensed engineer or contractor in the jurisdiction, that the building meets the energy savings requirement. It is based on modeling with approved software and it is what supports the deduction on the return.
Can 179D be claimed more than once on the same building?
Since 2023, yes. A building can qualify again after three years, or four years for an allocated deduction, if new qualifying work is done. Before 2023 it was once per building.
Educational content only, not tax or legal advice. Dollar figures are the statutory amounts and are adjusted for inflation each year, and the rules depend on when a property was placed in service. Talk to a licensed CPA before you act on any of it.
Designed a public or nonprofit building?
If your firm designed schools, municipal buildings, hospitals or universities in the last few years, there may be an allocation you earned and never requested. Tell us the projects and we will tell you which ones are worth pursuing. Start with the 179D overview, send us the details, or call +1 (586) 899-1003.
Keep Reading