What is a rooftop Solar PV System?

A rooftop Solar PV System, also known as a solar electric system, is a solar PV system where the solar panels are installed on the roof of residential, institutional, social, government, industrial, or commercial buildings. Multiple solar panels are joined together to create a solar array.

What is the capacity of a residential rooftop solar PV system?

The residential rooftop solar PV system typically has a capacity range of up to 50 kW. The deployment of residential rooftop solar PV systems has increased significantly in recent years across the world, owing to the declining costs and the government’s supportive policies.

Does rooftop solar really work?

In 2024, rooftop solar was the fastest-growing source of electricity worldwide, according to data from the U.S. Energy Information Administration. Yet many homeowners still hesitate because of cost, myths and confusion about how the technology actually works.

Is rooftop solar cost-competitive?

However, according to a 2025 McKinsey article, rooftop solar remains cost-competitive in many markets, with the lifetime cost of electricity generated often cheaper than grid power.

Why are rooftop solar panels more affordable?

For homeowners, these global cost trends translate into more affordable rooftop solar installations. As utility-scale solar prices fall, residential systems also benefit from cheaper panels, lower installation costs, and more competitive financing.

How long do solar panels last?

Since panels typically last 25 years or more, the next 19 years are essentially free electricity. Regardless of these positive cost trends, upfront solar costs can still feel steep. Especially since several factors such as roof orientation, shading, and expertise of installer can limit viability.