Section 179D Commercial Energy Deduction Calculator 2026
Calculate the Section 179D energy efficient commercial building deduction. Up to $5/sqft for HVAC, lighting, and envelope improvements with prevailing wage.
Building Details
Gross square footage of commercial building
%
Must be at least 25% to qualify %
21% C-corp, up to 37% pass-through $
Cost of qualifying energy improvements $0
Total 179D Deduction
$0.00/sqft
Deduction per Sq Ft
$0
Tax Savings
0%
Tax Savings / Cost
Section 179D Deduction Breakdown
How Section 179D Works
Section 179D provides an immediate first-year deduction for energy-efficient improvements to commercial buildings. Unlike depreciation which spreads deductions over 39 years, 179D lets you deduct qualifying costs immediately. The Inflation Reduction Act dramatically increased the cap to $5/sqft and tied the maximum to prevailing wage compliance.
The Formula
Base Rate (no prevailing wage): $1.00/sqft
Maximum Rate (prevailing wage met): $5.00/sqft
Partial System: each of 3 systems = up to 1/3 of max per sqft
Min energy reduction: 25% (scales up to 50%+ for full deduction)
Total Deduction = Rate per sqft Γ Building Square Footage
Maximum Rate (prevailing wage met): $5.00/sqft
Partial System: each of 3 systems = up to 1/3 of max per sqft
Min energy reduction: 25% (scales up to 50%+ for full deduction)
Total Deduction = Rate per sqft Γ Building Square Footage
Example
50,000 sqft building, all systems improved, 50%+ energy reduction, prevailing wage met:
Deduction rate: $5.00/sqft
Total deduction: 50,000 Γ $5.00 = $250,000
At 21% corp rate: Tax savings = $250,000 Γ 21% = $52,500
Cost of improvements: $800,000 | Tax savings/cost: 6.6%
Deduction rate: $5.00/sqft
Total deduction: 50,000 Γ $5.00 = $250,000
At 21% corp rate: Tax savings = $250,000 Γ 21% = $52,500
Cost of improvements: $800,000 | Tax savings/cost: 6.6%
Sources and References (click to expand)
- IRC Section 179D β Energy Efficient Commercial Buildings Deduction
- IRS Notice 2006-52 β Section 179D Guidance
- Inflation Reduction Act of 2022 β Section 13303 (179D Expansion)
- ASHRAE 90.1 β Energy Standard for Sites and Buildings Except Low-Rise Residential
- IRS Form 7205 β Energy Efficient Commercial Buildings Deduction
Extended
Multi-Building 179D Project Calculator
Calculate 179D deductions across multiple buildings with per-building energy data, SVG bar chart, ROI table
Calculate 179D deductions across multiple buildings. Enter per-building square footage, energy reduction, and systems improved. Rate: $5/sqft max (prevailing wage).
179D Deduction by Building
| Building | Sq Ft | Energy Red. | Rate/sqft | Deduction | Tax Savings (21%) | Cost | Savings/Cost |
|---|
Frequently Asked Questions
What is the Section 179D commercial building energy deduction?
Section 179D allows building owners (or designers of government buildings) to take an immediate tax deduction for installing energy-efficient commercial building property. The deduction applies to three building systems: HVAC, interior lighting, and building envelope. As updated by the Inflation Reduction Act, the maximum deduction for 2026 is $5.00 per square foot (with prevailing wage and apprenticeship requirements met), up from the prior $1.80 cap.
What are the 2026 Section 179D deduction amounts per square foot?
For 2026: Base deduction (no prevailing wage) = $1.00/sqft. Maximum deduction (prevailing wage and apprenticeship met) = $5.00/sqft. The amount scales between these amounts based on the percentage of energy reduction relative to the ASHRAE 90.1 reference standard. Each of the three systems (HVAC, lighting, envelope) can qualify for a partial deduction of up to 1.67/sqft each.
Who qualifies to claim the Section 179D deduction?
Commercial building owners can claim 179D for improvements to their own buildings. For government, tribal, or tax-exempt owned buildings, the deduction can be allocated to the designer (architect, engineer, or contractor) who created the technical specifications. The building must be located in the US and the improvements must be placed in service during the tax year.
What energy reduction percentage is required for Section 179D?
The building must achieve at least 25% energy reduction compared to the ASHRAE 90.1-2007 reference standard (or later versions). Greater energy reductions qualify for higher deductions on a sliding scale. A 50% or greater reduction qualifies for the full deduction. Certifications must be provided by a qualified engineer or contractor using approved software.
How does the 179D deduction differ from a tax credit?
Section 179D is a deduction, not a credit. A $5/sqft deduction on a 100,000 sqft building = $500,000 deduction, which at a 21% corporate rate saves $105,000 in taxes. A credit would save the full credit amount directly. However, 179D is still highly valuable because it converts capital expenditures into immediate ordinary deductions, accelerating the tax benefit significantly versus standard depreciation.