Residential Rooftop Solar Overview

Energy bill costs for residential buildings are telescopic in nature. As the energy consumption increases day to day, tariff increases in corresponding slabs. So Go with solar.

Evaluating the case for Rooftop Solar Photo-Voltaic System

To help evaluate whether a residential rooftop solar system will work for a customer, the customer needs to consider several factors.

Firstly, availability of Sunlight – Is sufficient sunlight available for most of the day, throughout the year? India has one of the highest solar irradiation levels in the world and plenty of sunlight.

Secondly, availability of rooftop space for the system size needed – Is there sufficient shadow-free area on the rooftop? Typically, a 1 kWp system requires 100 sq. ft of shadow-free area on the rooftop.

Additionally, economics of the investment – Are the savings worth the investment? Savings depend on the customer’s cost of power and effective savings.

For residential societies / apartment complexes, a larger system is more suitable as the energy consumption is higher. The size of system depends on the available rooftop .

Net Metering

In a grid-connected solar system, any excess solar power generated (units generated – units consumed from DISCOM) can be fed back to the grid.

Net metering framework is offered by a state under which the power provider (DISCOM) essentially pays you the retail price (as decided by the DISCOM) for the electricity you feed back into the grid.


Unique Sun Power can installed of Rooftop Solar Power Plant include System Design & Engineering, Construction of the Plant, Quality Check, Commissioning, Handover to Customer, and Post-installation O&M Services.

Economics of a Residential Rooftop Solar System

The customer saves money through the generation of solar power. Other than the upfront cost of the rooftop solar system, there is minimum maintenance cost involved. The maintenance typically involves regular cleaning of the panels and ensuring no obstructions to the panels. The lifetime of a rooftop solar system is approximately 25 years.

A customer’s savings can be calculated using the following formula:

  • Electricity bill savings / year = (units generated / year) * (cost of power).

For example, a residential customer with a 3 kWp rooftop solar system and a residential power cost of Rs 7 / unit will save approximately Rs 31,500 per year.

(Also note that the power costs are continuously rising!)

Residential Solar – A Key Component of Smart Cities

Sustainable Environment is an important objective of both missions. Residential Rooftop Solar will act as an important agent in the urban transformation by harnessing the renewable energy source (solar) and reducing the emission of greenhouse gases such as COx, SOx and NOx.

Installing a 3 kWp solar system reduces the emission of COx (greenhouse gas) by 3700 kgs and is equivalent to planting 170 mature trees

Applicable Policy


(Net metering is a billing system that allows rooftop owners having solar system installed at their rooftop to sell any excess electricity generated from solar system to local electricity utility)

  • Min 1 kWp
  • Max 1 MWp
Voltage level:
  • Upto 6 kW, 230V- single phase
  • Above 6 kW and upto 100 kW, 415 V-Three phase
  • Above 100 kW, 11 kV-Three phase (HT)
  • Cumulative capacity of all solar systems installed in your area shall not exceed 30% of distribution transformer capacity2 in your area.
Ownership options
  • Self ownership (CAPEX model)
Billing Mechanism
  • Annual (April to March)
  • Any unadjusted electricity credits shall be paid as per the rates notified by GERC.
  • Exempted from Transmission Charge, Transmission Loss, Wheeling Charge, Cross Subsidy Surcharge, Electricity Duty

  • Subsidy Applicable as per SECI guidelines


  • Loan for solar as a part of home loan/home improvement loan
  • Loan upto Rs. 10 lacs available for individuals under Priority sector lending

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