Size a system from your commercial bill
Use the units on your commercial electricity bill. The calculator models the Tamil Nadu commercial tariff (TNPDCL LT V (commercial energy only)) with an energy rate of ₹10.45 per unit, and assumes about 120 units of generation per kW each month.
As an example, a business using 2400 units over a two-month bill averages 1200 units a month. That suggests 10 kW, modelled at about 1100 sq ft of roof space and a planning budget of ₹5.50 lakh–₹7.00 lakh before any other costs. Your own bill and roof decide the real answer.
Planning figures for larger systems
| Capacity | Modelled generation | Modelled roof space | Illustrative budget |
|---|---|---|---|
| 5 kW | about 600 units a month | about 550 sq ft | ₹2.75 lakh–₹3.50 lakh |
| 10 kW | about 1200 units a month | about 1100 sq ft | ₹5.50 lakh–₹7.00 lakh |
| 15 kW | about 1800 units a month | about 1650 sq ft | ₹8.25 lakh–₹10.50 lakh |
| 20 kW | about 2400 units a month | about 2200 sq ft | ₹11.00 lakh–₹14.00 lakh |
Sizes above 3 kW use an illustrative allowance of ₹55,000–₹70,000 per kW, not a quotation. A written quotation follows a site assessment.
Subsidies and tariffs for businesses
The household subsidies described on this site apply to residential connections only. Commercial installations do not qualify for them, so a business plan should not count on that assistance. Confirm your actual tariff category and daytime load pattern with your electricity connection rather than applying household savings assumptions.
What to check before you commit
- Who can authorise work on the roof, especially if the building is shared or rented.
- Usable roof area, shade, safe access and structural suitability.
- When the business uses power. The model assumes 70% of generation is used directly.
- The equipment, scope and exclusions listed in the written quotation.
- Who answers service questions after commissioning.
The installer checklist and the cost guide explain what a comparable quotation includes.
Where Arc Solar works
Business enquiries are welcome from Pernambut, Vellore, Ambur, Gudiyattam, Vaniyambadi and across Vellore, Tirupattur, Ranipet, Chennai, Kanchipuram. These are service areas, not separate branches. See the service areas page for details.
Start with your bill
Enter your units in the estimate calculator and choose Business, or contact Arc Solar by phone, WhatsApp or email.