Commercial ITC still available: The Section 48E Investment Tax Credit provides a 30% federal tax credit for business solar installations in 2026. Unlike the residential 25D credit (expired Dec 31, 2025), Section 48E has no current expiration date.
Quick Answer
Commercial solar installation in 2026 costs $1.80–$2.80 per watt installed — lower per-watt than residential due to economies of scale. A 50 kW rooftop system for a small business runs $90,000–$140,000; a 100 kW system is $180,000–$280,000. Critically, commercial solar tax credits are still available in 2026: the Investment Tax Credit (ITC) under Section 48E provides a 30% federal tax credit for commercial and business solar installations, unlike the residential 25D credit which expired December 31, 2025.
| System Size | Typical Use Case | Installed Cost (before ITC) | After 30% ITC (48E) |
|---|---|---|---|
| 25 kW | $45,000 | $70,000 | After ITC: $31,500–$49,000 |
| 50 kW | $90,000 | $140,000 | After ITC: $63,000–$98,000 |
| 100 kW | $180,000 | $280,000 | After ITC: $126,000–$196,000 |
| 250 kW | $400,000 | $600,000 | After ITC: $280,000–$420,000 |
| 500 kW (ground mount) | $750,000 | $1,200,000 | After ITC: $525,000–$840,000 |
This is the most important distinction between commercial and residential solar in 2026: commercial solar tax credits are still fully available. The residential Section 25D credit expired December 31, 2025. However, the commercial Investment Tax Credit under Section 48E — which covers solar installations for businesses, nonprofits, and commercial property owners — remains in effect at 30%. Bonus credits are available for projects in energy communities (+10%) and projects meeting domestic content requirements (+10%), potentially bringing the total credit to 50%. Third-party ownership (TPO) structures — where a developer owns the system and sells power to the business via a PPA — also remain eligible for the 48E credit, making $0-down commercial solar still financially viable.
System size and economies of scale
Commercial solar benefits from volume pricing on equipment and labor. Per-watt costs drop from $2.80/W for small 25 kW systems to $1.80/W or less for 250 kW+ projects.
Roof vs. ground mount
Rooftop commercial systems are cheaper to permit but may require structural engineering assessments. Ground-mounted systems cost more per watt but allow optimal orientation and easier maintenance.
Utility interconnection tier
Systems above 100 kW often require a more complex utility interconnection study, adding $5,000–$50,000 in soft costs and 6–18 months of processing time.
Ownership vs. PPA/lease
Businesses that can use the 48E tax credit directly benefit most from ownership. Businesses without sufficient tax appetite (nonprofits, low-profit entities) are better served by TPO structures where the developer takes the credit.
Bonus credit eligibility
Energy community bonus (+10%) applies to projects in coal closure or fossil fuel employment communities. Domestic content bonus (+10%) applies when panels and structural components are US-manufactured. These bonuses can materially improve project economics.
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Yes — the commercial Investment Tax Credit (ITC) under Section 48E is still fully available for business solar installations in 2026. The 30% credit applies to the full installed cost of commercial solar systems. This is a key difference from residential solar: the residential 25D credit expired December 31, 2025, but the commercial 48E credit remains in effect.