Why is commercial solar so much cheaper per watt than residential?

Scale. Commercial rooftop installs run roughly $1.20–$2.00 per watt versus about $2.95 for residential, because crews mount large arrays on simple flat roofs with shared mobilization and engineering costs spread across far more panels.

How accurate is the depreciation estimate?

We model 5-year MACRS with 100% bonus depreciation as a one-time tax shield at a combined ~26% rate, with the basis reduced by half the ITC. Your actual benefit depends on your tax position, entity type, and state — confirm with your CPA.

Do I need to enter roof size?

No. Leave it blank and the calculator sizes the array to your consumption. Enter usable roof or land area when you want the system constrained to what you can physically host.

::COMMERCIAL_ROI_TOOL

Commercial Solar Calculator: ROI, 48E Credit & Payback

Model your business's solar + battery project in 60 seconds. Enter your monthly electric bill and state to see system size, the Section 48E tax credit, MACRS depreciation, net cost, and payback — with optional battery storage and bonus-credit adders.

::INPUT_PARAMETERS

Monthly Electric Bill (USD)

State

Facility Type (optional)

Usable Roof / Land (sq ft, optional)

Commercial solar (§48E) is different — but the clock moved. Projects that missed the Jul 4, 2026 beginning-of-construction deadline generally must be placed in service by Dec 31, 2027. Figures on this page are general information, reviewed Oct 2026, not tax advice.

How the Numbers Stack Up

Commercial solar is often discussed alongside the Section 48E Clean Electricity Investment Credit and 5-year MACRS depreciation. A 30% base for prevailing-wage and apprenticeship rules, or projects under 1 MW, and adders sometimes described as reaching 50%, are commonly cited. They are not a settled quote.Commercial solar (§48E) is different — but the clock moved. Projects that missed the Jul 4, 2026 beginning-of-construction deadline generally must be placed in service by Dec 31, 2027. Figures on this page are general information, reviewed Oct 2026, not tax advice.

This model also treats solar as 5-year MACRS property and illustrates bonus depreciation at a combined ~26% tax rate. A result that cuts net cost by more than half, or a 4–7 year payback, is an illustration, not a settled outcome.

Projects that missed the July 4, 2026 beginning-of-construction deadline generally must be placed in service by December 31, 2027. Commercial solar (§48E) is different — but the clock moved. Projects that missed the Jul 4, 2026 beginning-of-construction deadline generally must be placed in service by Dec 31, 2027. Figures on this page are general information, reviewed Oct 2026, not tax advice.

Commercial Solar Calculator FAQ

It models system size from your monthly bill and state, then applies an illustrative Section 48E rate (a commonly cited 30% base, or adders sometimes described as reaching 50%) and 5-year MACRS. Those rates are not a settled quote. If you add storage, it also models battery cost and demand-charge savings. Reviewed Oct 2026, general information, not tax advice.

Guide

Commercial Solar + Battery ROI →

Credit

Section 48E Tax Credit →

Residential

Home Solar Calculator →