Tax Credits for Energy Efficiency Retrofits: Turning Compliance Costs Into Capital Returns

Updated July 6, 2026.

If you own commercial property in California and a retrofit was on your three-year plan, start with the hard part: the window for new Section 179D projects is closed. Under the One Big Beautiful Bill Act, signed July 4, 2025, the Energy Efficient Commercial Buildings Deduction does not apply to any property on which construction begins after June 30, 2026. That date has passed. A new project you break ground on this month will not qualify — full stop, no false hope. This is a refresh of a piece that once told owners to move before the deadline. The deadline is now history, so the value of this update is telling you exactly what died and what still works.

What Actually Died

The deduction itself was not repealed for the past — it was cut off at the start line for the future. As of July 1, 2026, if your shovel had not gone into the ground, the federal benefit is no longer available for that project. What that costs depends on how the work would have been built. Without prevailing-wage and apprenticeship compliance, the ceiling was up to $1.19 per square foot — on a 50,000 SF building, roughly $59,500 of first-year deduction. With prevailing-wage and apprenticeship compliance, the ceiling was up to $5.94 per square foot — on that same building, roughly $297,000. Either way, it is a real incentive, and it is gone for new work. Owners who were mid-planning are right to feel the loss.

What Still Qualifies

Three things survived, and they are not consolation prizes.

First, projects that began construction on or before June 30, 2026 preserve eligibility even if the building is placed in service later. The IRS recognizes two ways to have "begun" by the deadline: the Physical Work Test — significant on-site work started by June 30 — or the 5% Safe Harbor, meaning at least 5% of total project cost was incurred by that date. If you have work in that category, the up-to-$1.19-per-square-foot base benefit, or up-to-$5.94 with prevailing wage and apprenticeship compliance, is still on the table when the project is placed in service. Do not assume you missed it; check the two tests first.

Second, and this is the one most owners have never run: retroactive 179D claims on your existing portfolio are still wide open. Qualifying buildings constructed or retrofitted back to 2006 can be claimed today through Form 3115, a change in accounting method — no amended returns required. This look-back window is unaffected by the sunset. Most LA and OC owners have simply never had a study run on energy work they already paid for years ago. That is money on the table right now, not a deadline to race.

Third, the rest of the recovery stack is untouched. A cost segregation study still breaks a retrofit into components — lighting, HVAC, controls, envelope — and reclassifies what qualifies into shorter recovery lives, pulling deductions forward against today's income. California utility and state incentive programs still reduce net project cost before any federal benefit applies. Neither depends on 179D, and both still stack with a retroactive claim.

The Stack Still Recovers Real Money

"In our underwriting, a properly sequenced efficiency retrofit typically recovers thirty to fifty percent of project cost through 179D, accelerated depreciation, and utility incentives — before counting a dollar of energy savings," says Francisco Williams, CCIM, founder of Williams Capital Advisors. "Owners who treat compliance as pure cost are leaving real money on the table."

That logic held before the sunset and it holds after — the difference is that for new projects, the 179D leg of the stool is gone, and the weight now shifts to the retroactive claim, cost segregation, and utility incentives. For work already started or already done, the full stack is still in play.

What To Do Now

The single most useful move this quarter is a 179D look-back study on energy work done anywhere on your portfolio since 2006 — the Form 3115 window is still open, it costs nothing to scope, and it is the one action the sunset did not touch. When we run that study, we also check two things beside it: whether any project that broke ground on or before June 30, 2026 still qualifies under the Physical Work Test or 5% Safe Harbor before you write it off, and whether cost segregation and utility incentives are captured in every retrofit budget going forward, since neither ever depended on the federal deadline.

A real incentive died on June 30. But the owners who paid for qualifying work in the last twenty years, and never looked back, still have an open claim — and that is action you can take this quarter, not a clock you missed.

Want the Numbers on Your Building?

Williams Capital Advisors will scope a 179D look-back at no cost, and can fold the result into a complimentary Broker Opinion of Value so you know what your asset is worth today and what the surviving retrofit math means for its value tomorrow. Sources: IRS FAQ on the OBBBA modifications to Section 179D (irs.gov); analysis from Leyton US and CSSI Services. General information, not legal, tax, or investment advice.