Work out the net cost after central financial assistance, the years to pay back and the saving over the system life for a home rooftop solar system.
How to use it. Enter the installed price from a registered vendor's quotation, the central financial assistance (CFA) you expect, and your expected bill saving in year one. Under PM Surya Ghar: Muft Bijli Yojana the CFA for residential households is widely published as ₹30,000 per kW for the first 2 kW and ₹18,000 for the third kW, so ₹30,000 for 1 kW, ₹60,000 for 2 kW and a maximum of ₹78,000 for 3 kW or more. Confirm the current amount on the national portal before you sign, because scheme terms can be revised.
Estimating the saving. A rooftop system's yearly output depends on location, tilt, shading and cleaning. As an illustrative assumption, 1 kW might generate around 1,200–1,500 units a year in much of India. Multiply the units you will use yourself or export under net metering by the rate you would otherwise pay at your top slab, since solar units displace your most expensive units first. Example: 3 kW × 1,300 units = 3,900 units; at an illustrative ₹5.60 average avoided rate that is about ₹21,800 a year.
Formula. Net cost = installed cost − subsidy. Each year's saving grows by the tariff increase you enter. Payback is the point where cumulative savings equal the net cost. The final figure is savings over the chosen period minus net cost.
Limits. It ignores inverter replacement (often needed once in the life of a system), panel degradation, loan interest if you finance it, and changes in your state's net metering rules or free-power scheme. If your state already gives you free units, your avoided cost may be close to zero and payback much longer. All default numbers are illustrative.
Bill Calculations, Gas Costs and Checklists
The ₹30,000, ₹60,000 and ₹78,000 central assistance, how net metering shows on your bill, sizing to your units and a payback example in rupees.
