Commercial solar capacity calculator
What your roof, your load and your sanctioned demand actually allow, and which of the three is the real ceiling.
Your details
Printed on your bill. This is usually the real ceiling.
Clear area only. Exclude plant rooms, ducting and walkways.
Your estimate
Solar you can installEstimated
35.5 – 40.7 kW
Your consumption is the limit. Your roof and your sanctioned load both allow more, but a system larger than this exports the surplus at the lower net-metering rate.
- What binds it
- consumption
- Consumption would justify
- 35.5 – 40.7 kW
- Panels
- 70 – 81
- Generation
- 4,362 – 5,732 units / month
- Over a year
- 53,067 – 69,736 units
The constraint that decided the number above.
Sized against your bill alone, ignoring roof and load.
At the module size currently installed.
Against the roughly 5,000 units you use.
Summer runs above this, monsoon below.
This is an estimate, not a quote.
This is an estimated range based on average conditions in your area. Your actual numbers depend on site-specific factors we verify before quoting.
Rates last verified 2026-08-06
Get the number we stand behind
Origian Power stands behind the number our engineer gives you after a free site visit — not the number above.
- Your sanctioned load as recorded by the DISCOM, not as remembered
- Structural capacity of the roof, which a survey establishes
- Where the plant room and cable routes can actually go
The ceiling is usually paperwork, not roof space
Three separate limits apply to a commercial system, and only one of them binds. Your consumption sets what is worth installing, your roof sets what physically fits, and your sanctioned load sets what the DISCOM will approve. The smallest wins.
In practice the sanctioned load binds more often than businesses expect, which makes it the useful thing to establish first: raising it is an application rather than a construction problem. The commercial ROI calculator takes the resulting size and works out what it returns.
Questions about this estimate
What is sanctioned load, and why does it cap my system?
It is the maximum demand your DISCOM has agreed to supply, printed on your bill. Rooftop solar is approved against it, so a system above your sanctioned load will not clear feasibility however much roof you have. Raising it is an application, not a rebuild.
Can I install more than my consumption justifies?
Technically often yes, commercially rarely. Surplus is exported at the net-metering rate rather than the commercial tariff you avoid, so the value of each extra kilowatt falls sharply once you pass your own usage.
How much roof does a commercial system need?
Roughly 80 to 100 square feet per kilowatt of clear, unshaded area. Plant rooms, ducting, walkways and setbacks all come off the total, which is why the usable figure is normally well below the measured roof.
What if my roof cannot take the load?
Then ground mounting or a carport is the alternative, and both are costed differently. Structural capacity is one of the first things a survey checks, because it can change the whole approach rather than just the size.
Ready to find out what solar would do for your bill?
Book a free site survey. We assess your roof, your consumption and your connection, then tell you what is actually worth installing.