Solar Panel Structures: Choosing Pre-GI or HDGI for 25 Years of Strength

As solar panel installations become more common on Indian rooftops, choosing the right mounting structure has become an important decision for homeowners seeking long-term reliability.

Two types of galvanised iron structures dominate the market: Pre-GI (pre-galvanised iron) and HDGI (hot-dip galvanised iron), both designed to protect the metal frame from corrosion.

In Pre-GI structures, the metal sheet is coated with zinc before it is cut and shaped into the final frame. This process is generally faster and cheaper, but the coating can be thinner and more vulnerable to damage at the edges where the metal has been cut.

HDGI structures, by contrast, are shaped first and then dipped entirely in molten zinc, producing a thicker and more even coating across the whole structure, including edges and joints.

This extra protection makes HDGI structures more resistant to rust, which is particularly important given that solar panels are typically expected to remain in service for around 25 years.

Industry experts argue that although HDGI structures may cost more initially, their greater durability can reduce maintenance costs and extend the overall lifespan of a rooftop solar system, making them a better long-term investment.

Separately, reports on consumer electricity bills have highlighted mixed experiences among solar users. Some households have seen their bills fall dramatically, with one report citing a monthly bill of just ₹800 after installing solar panels.

However, other users have expressed frustration over fixed charges that remain part of their electricity bills regardless of how much power they generate from solar. According to the reports, around 1.37 lakh consumers are currently affected by these charges, collectively paying approximately ₹10 crore every month.

This has raised questions about whether current billing structures fully reflect the savings that solar adopters expect, even as the technology itself becomes more efficient and widespread.

Additional coverage has also compared the electricity output of different solar panel types, aiming to help consumers understand which panels generate the most power for their investment.

Together, these reports suggest that getting the best value from a home solar system depends not only on selecting an efficient panel, but also on choosing a durable structure and understanding local billing rules.