Imperial Metric
Commercial Solar Calculator · 2026 Programs

Is commercial solar worth it
for your building?

Redo your energy with commercial solar — enter your building details for a savings estimate with ITC adders, MACRS depreciation, demand charge analysis, and PPA comparison.

New Commercial Solar
Existing Solar
Battery Only
Used to look up your utility rate, solar irradiance, and local incentives.
1
Your Building
sq ft
1
2
3+
Flat (ballasted)
Low-slope
Standing seam
Ground-mount
Multi-zone
sq ft
Total roof area. Fire code setbacks & pathways (~33–40%) are deducted automatically.
M-F 8am-5pm
6 days
24/7
Roof Zones
Define up to 4 roof zones with different tilt and orientation. PVWatts runs per-zone.
2
Energy Profile
$
Your typical monthly commercial electric bill.
Auto-populated when you enter your address.
$/kW/mo
Peak demand charge on your commercial rate. Auto-estimated by building type.
kW
Highest monthly demand reading. Estimated from bill if unknown.
3
System Design
Cover 100%
Cover 75%
Maximize roof
Custom kW
Budget
Mid-Range
Premium
String (3-phase)
Central
Microinverters
None
Minimal (5%)
Moderate (15%)
Heavy (30%)
Severe (50%)
Bifacial panels? Best on flat commercial roofs with light-colored membranes (TPO/PVC).
Include commercial battery storage? Battery for demand charge reduction and backup power.
%
Federal 21% + state corporate tax. Used for MACRS benefit.
Cash
Commercial Loan
PPA
ITC Adders (IRA)
Prevailing wage & apprenticeship Required for 30% base ITC (otherwise 6%). Most commercial projects qualify.
Domestic content (+10%) Steel, iron, and manufactured products meet domestic content thresholds.
Energy community (+10%) Located in a brownfield, coal community, or area with high fossil fuel employment.
Low-income community (+10% or +20%) Located in a low-income census tract or serving low-income residents.
Use Section 179 instead of MACRS? Full cost deduction in Year 1 (up to $1.16M cap). Best for smaller systems.
%/yr
Historical average is ~2.5–3.5%/yr. Used for 25-year projections.
%/yr
Typical: 0.3–0.7%/yr. Premium panels degrade slower.
%
Includes wiring, soiling, mismatch, clipping. NREL default: 14%.
25 years
30 years
$/kWh
Monthly Production vs. Consumption
Solar generation (yellow) compared to building electricity usage (gray) by month.
Cumulative Savings Over Time
When your solar investment breaks even, including MACRS depreciation benefits.

Assumptions & Methodology

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🌡️ Reduce heating costs with a commercial heat pump → ⚡ Add workplace EV charging for your employees →