On-Grid vs Off-Grid vs Hybrid Solar: Which Rooftop System to Choose

An on-grid system feeds solar power into your home first and exports any surplus to the grid through a bi-directional net meter, with no battery. During the day your appliances run on solar; when solar isn't enough — at night or on cloudy days — you draw from the grid as usual, and your bill is based on the net units.

The trade-off is backup: an on-grid inverter must shut down during a power cut. This anti-islanding protection is a safety requirement so that your system cannot energise grid lines that linemen are working on. So an on-grid system delivers the best savings per rupee invested, but no power during outages.

An off-grid system runs your load from solar panels and a battery bank, completely independent of the grid. Panels charge the battery through a charge controller during the day, and the inverter supplies your appliances from the battery around the clock.

Off-grid makes sense where there is no grid connection or it is very unreliable — farmhouses, remote sites, tube wells and cabins. It needs a large battery sized for your night-time use and for cloudy days, which raises cost and adds battery replacement over the system's life. Any surplus on sunny days is simply wasted once the battery is full.

A hybrid system combines both: it is connected to the grid with net metering, and it also has a battery that takes over automatically during a power cut. A hybrid inverter manages solar, battery and grid together — powering your load from solar first, charging the battery, exporting surplus, and switching critical loads to the battery when the grid fails.

Hybrid is the right choice when you want the savings of on-grid solar but also can't tolerate power cuts — homes with frequent outages, clinics, offices with computers and servers, and shops. Modern hybrid inverters paired with lithium (LFP) batteries switch over fast enough that computers and Wi-Fi keep running.

The simplest way to choose is to ask two questions: do you have a grid connection, and do you need power during outages?

Size a rooftop solar system by your average monthly units, not by your connected load. In north India, including the Tricity, 1 kW of well-installed rooftop solar typically generates roughly 4 units a day on average across the year — around 110–130 units a month, with more in summer and less in winter and during fog.

So a home using about 400 units a month would typically look at a system of around 3–4 kW. Check your last 12 months of bills, since summer AC use can double consumption. For on-grid systems, the size you can install is also capped by your sanctioned load and your DISCOM's rules.

For off-grid and hybrid systems, also size the battery: estimate the kWh you need during outages or at night, then allow for the battery's usable depth of discharge and inverter losses.

Net metering lets an on-grid or hybrid system export surplus power and offset it against the units you import, so you pay only for the net consumption. It requires an application to your electricity distribution company (DISCOM), a technical feasibility approval, installation, inspection and replacement of your meter with a bi-directional net meter.

For residential rooftop solar, the central government's PM Surya Ghar: Muft Bijli Yojana offers a subsidy that is applied for through the national rooftop solar portal. The general process is: register on the portal, apply with your electricity consumer details, get DISCOM feasibility approval, have the system installed by a vendor registered for the scheme, apply for net metering and inspection, and then submit the commissioning details and bank information so the subsidy is credited. Subsidy amounts and eligibility are set by the scheme and can change, so always check the current terms on the official portal before you commit.

Shading is the biggest performance killer — even partial shade on one panel can drag down the output of a whole string. Before installation, the roof should be checked for shadows from water tanks, parapets, neighbouring buildings, trees and mumty rooms across the day and across seasons, since the winter sun sits lower in the sky.

In India, panels generally face south, tilted at an angle close to the site's latitude for the best year-round output. The mounting structure should be hot-dip galvanised or aluminium, anchored firmly to resist wind, and raised enough to allow cleaning and to keep water off the roof around the legs. Leave walkways between rows so panels can be cleaned and inspected safely.

Every rooftop solar system needs proper earthing and, on exposed roofs, a lightning arrester. Common practice is separate earth pits for the DC side (panel frames and structure), the AC side (inverter and output) and the lightning arrester, all bonded together.

Good earthing protects people from shock, protects the inverter from surges, and prevents the "earth fault" alarms that make inverters shut down. Surge protection devices (SPDs) on both the DC and AC sides add another layer against lightning-induced surges.

Solar needs little maintenance, but dust is the main enemy in north India. Panels should be cleaned regularly with plain water and a soft brush — more often during dry, dusty months — and generation should be checked on the inverter or app so any drop is spotted early.

Electrons designs and installs on-grid, off-grid and hybrid rooftop solar for homes, shops and industry across Zirakpur, Panchkula, Chandigarh and Mohali. We visit the site, check your bills, roof and shading, recommend the right system type and size, install the panels, inverter, structure, earthing and lightning arrester, and test the system before handover. We also support you with net-metering and subsidy paperwork, and keep the system performing with cleaning, output checks and AMC.