Solar panels for India

Most homes now compare mono panels

Monocrystalline modules dominate new residential quotes because they produce more power from a limited roof area than older polycrystalline models. Many current modules use half-cut cells and technologies such as TOPCon. The label matters less than the tested model, warranty terms and the installer’s design.

Read the data sheet, not the sales label

Check rated power in watts, module efficiency, dimensions, weight, temperature coefficient, product warranty and performance warranty. A performance warranty describes expected degradation. It is not the same as a product warranty covering defects.

For subsidy-linked work, modules must meet the scheme’s domestic content requirement. Ask the vendor to identify the exact approved make and model before installation. Keep serial-number records and invoices.

Start with shade and usable area

A rough allowance is 80 to 100 sq ft per kW, including gaps and service access. Water tanks, parapets, lift rooms and nearby trees can cast shade. Even a small shadow at the wrong time can pull down a string of panels.

A sound installer should inspect the roof, note shade across the year, check drainage and design safe walkways. The structure must suit the roof and local wind conditions. Do not block rainwater flow or routine tank access.

Six checks before you choose

1. Get the exact model number, not only the brand.
2. Confirm DCR compliance if you plan to claim central assistance.
3. Ask for a roof layout with panel count and orientation.
4. Compare annual generation, not a best-day claim.
5. Read who handles a warranty claim and how.
6. Check the inverter, protections, structure and workmanship in the same detail.

Next, compare inverter types and the full installation process.

Wattage and efficiency answer different questions

Panel wattage is the rated output under laboratory test conditions. Efficiency is the share of sunlight converted into electricity over the panel area. A higher-watt panel can be physically larger, so wattage alone does not prove that it uses roof space better.

Efficiency matters most when usable roof area is tight. If the roof has plenty of clear space, layout, product quality, temperature behaviour and price can matter more than a small efficiency difference. Ask the installer to show how many kW fit on the actual roof with safe access gaps.

How many panels do you need?

The exact array can be slightly above or below the named capacity. The inverter voltage and current limits must accept the final string design.

ALMM, DCR and BIS are not the same thing

These terms often appear together in quotes, but they answer different questions. The Approved List of Models and Manufacturers, or ALMM, is maintained by MNRE for projects where the order applies. The Domestic Content Requirement, or DCR, concerns the origin of cells and modules for schemes that require domestic content. BIS standards and compulsory registration cover product testing and safety requirements.

For a PM Surya Ghar subsidy project, ask the vendor to confirm the exact module model and its DCR eligibility in the live scheme process. Do not accept a brand name as proof. One manufacturer can sell several models with different listings and specifications. Save the model number, serial numbers, invoice and portal record.

MNRE updates ALMM lists often. At this review, its module List-I carried an update dated 3 August 2026 and its cell List-II had a revision dated 21 August 2026. Check the current lists that apply to your project rather than relying on an old screenshot.

How Indian heat, clouds and dust affect output

Panels need sunlight, but very hot cells produce less power than the same panels at a lower cell temperature. The temperature coefficient on the data sheet estimates this change. Good airflow below the module helps release heat.

Cloudy weather reduces output but does not normally stop generation. Monsoon months can produce less energy than clear months. Annual production matters more than one rainy day. Dust, bird droppings and construction residue can also reduce output, so compare monitoring data before and after safe cleaning.

Shade is often more damaging than buyers expect. A narrow shadow from a water pipe or parapet can affect several modules in a string. Multiple MPPTs, module-level electronics or a revised layout can help in some designs, but the first choice should be to avoid shade where possible.

Which direction is best?

South-facing modules at a suitable tilt often support strong annual output in India. East and west roofs can still work and may spread generation across morning and afternoon. The right layout depends on latitude, roof shape, shade, wind and when the building uses electricity.

Read four parts of the warranty

1. Product cover: defects in the module and materials.
2. Performance cover: the promised output level after stated years.
3. Claim method: evidence, testing and who pays for removal or transport.
4. Local support: the party that accepts and processes the claim in India.

A long performance warranty does not guarantee the full system. Inverters, connectors, structure, waterproofing and workmanship have separate cover. Keep the purchase invoice and serial-number list. Without them, even a valid product claim can become difficult.

Flexible panels solve a different problem from standard framed rooftop modules. They can suit curved or weight-sensitive surfaces. Check heat dissipation, mounting method, walking restrictions and warranty before using them as a replacement for framed glass modules.