Solar On-grid: cut your bill using the grid as your battery

An on-grid or grid-tied solar system is a rooftop photovoltaic installation connected to the utility supply, with no batteries. It generates during daylight to offset what you would otherwise buy, and exports any surplus to the grid. At night and on dull days you simply draw from the grid as before.

Net metering is the arrangement that lets your surplus generation flow back into the grid and be credited against what you import. A bidirectional meter records both directions and you are billed on the net figure. It is what makes an on-grid system worthwhile without a battery, and it requires an application to your DISCOM.

No. A grid-tied inverter is required by law to shut down when the grid goes down, so that it cannot energise lines that linemen believe are dead. If you need power during outages you need storage: either a Solar Hybrid system, which keeps net metering and adds battery backup, or a full Solar Off-grid system.

As a planning rule, allow roughly 75 to 95 square feet of unshaded roof per kilowatt, depending on panel wattage and the mounting layout. Shading matters more than raw area: a roof that is partly shaded for part of the day may need a different layout or module-level electronics.

The physical installation of a domestic rooftop system is usually a matter of days. The overall timeline is normally governed by the DISCOM application and net-metering approval rather than by the construction work.

They differ in what gets measured and paid for. Net metering — the arrangement Origian’s on-grid systems use — nets your exported units against your imported units and settles the difference. Gross metering measures and pays for every unit generated, regardless of what you consumed. Net billing values exported units at a separate, usually lower, rate rather than netting them one-for-one against imports. Ask your installer which arrangement a quoted system is actually designed around, because the financial case changes considerably between them.

Yes — on heavily overcast and rainy days output falls well below a clear-sky day, since panels generate from diffuse light at a fraction of peak output rather than switching off. This is already reflected in the per-kW generation figures we give when we quote a system: they are yearly averages across the region’s actual weather, monsoon included, not a clear-sky estimate.

Generation drops for whichever panels fall into the new shade, and there is no automatic legal right in India to demand a neighbour preserve your access to sunlight. It is a genuine risk on dense plots, which is why a survey should account for what could realistically be built next door, not only what is there today, and why a layout that keeps one shaded string from dragging down the rest is worth the extra design time where the roof allows it.

Start from your bill, not a package name. The right size follows from your monthly consumption, the usable roof area, and how much shading you actually have — a 3kW system suits a light domestic load, most 3BHK homes with air conditioning land closer to 5kW, and a heavier load pushes higher still. Panel and inverter brand matter too, but only after sizing is right: an oversized system on the wrong tariff slab wastes money exporting surplus at the lower net-metering rate. Run your own bill through the savings calculator rather than picking a size because it is marketed as the best option.

No, and it is usually the most expensive mistake in solar. A lower quote often means a lower-tier panel or inverter, a thinner mounting structure, or workmanship without a real warranty behind it — costs that surface as replaced components or lost generation years after the invoice is paid. What is worth comparing across quotes: the product, performance and workmanship warranty terms (see our warranty page), whether the panels are ALMM-listed, and whether the installer stands behind the workmanship in writing. A system priced lower than everyone else’s is a reason to ask why, not a reason to sign.