CSIM
Incentive Program

§179D — Energy Efficient Commercial Buildings Deduction

FederalUp to $5.94/sf federal deduction
What it is

Up to $5.94 per square foot deduction for energy-efficient HVAC, lighting, and envelope improvements in commercial buildings. SUNSET WARNING: OBBBA terminates §179D for construction beginning after 6/30/2026.

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Check an Address — Free Snapshot

See whether a specific Chicago address sits inside the area that unlocks §179D — Energy Efficient Commercial Buildings Deduction, alongside every other incentive that touches that parcel.

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Who it's for

Commercial building owners, and designers working on government- or nonprofit-owned buildings (the deduction can be allocated to the designer when the owner is tax-exempt).

Where it applies

§179D — Energy Efficient Commercial Buildings Deduction is administered at the federal level. Depending on the program, eligibility may depend on the specific location, property type, or business activity rather than a single drawn boundary.

Boundaries are precise and change over time, so exact eligibility always depends on the specific address. The fastest way to know is to run a free snapshot for the parcel you have in mind.

What it can support

Typical range · Up to $5.94/sf federal deduction

  • +Up to $5.94 per square foot federal deduction
  • +Available for HVAC, lighting, and building envelope improvements
  • +Designers of tax-exempt-owned buildings can claim allocated deduction
How to apply
  1. 1Begin construction by 6/30/2026 to qualify
  2. 2Engage a qualified energy modeler to certify §179D compliance
  3. 3File Form 7205 with tax return
Fastest first move

Engage a §179D energy modeler before 6/30/2026 construction start

What you'll need
  • Qualified energy modeler certification
  • Building plans and energy model
  • Allocation letter (if designer claim on tax-exempt building)
What to verify

This page is a starting point, not eligibility, legal, or tax advice. Verify current requirements, deadlines, and boundaries with the administering agency before applying or spending money — program rules and funding change over time.

Official source & contacts
Official program source ↗
Internal Revenue Service (IRS)

Last verified 2026-05-21

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Check an Address — Free Snapshot

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