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.
| Type | Useful when | Watch for |
|---|---|---|
| Mono PERC | You want a common, proven module | Compare product age and warranty support |
| n-type TOPCon | Roof space is tight or you want newer high-output modules | Do not pay a large premium without a layout-based gain |
| Bifacial | The rear can receive reflected light on an elevated structure | A module placed close to a dark roof may gain little |
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
- Get the exact model number, not only the brand.
- Confirm DCR compliance if you plan to claim central assistance.
- Ask for a roof layout with panel count and orientation.
- Compare annual generation, not a best-day claim.
- Read who handles a warranty claim and how.
- Check the inverter, protections, structure and workmanship in the same detail.
Next, compare inverter types and the full installation process.
Common questions
How many panels make a 3 kW system?
It depends on panel wattage. For example, six 500 W modules total 3 kW DC. The final design must also fit the roof and inverter input limits.
Do solar panels work in cloudy weather?
Yes, at lower output. Annual estimates account for seasonal weather. Rain can also wash loose dust, but it does not replace inspection and cleaning where soiling is heavy.
Official sources
Rules and portal processes can change. Check these sources before committing money.