Housing societies across India face a persistent problem: the monthly electricity bill for common areas, lifts, corridor lighting, pump motors, car park lighting, security systems, gym, and clubhouse, runs ₹50,000 to ₹3,00,000 per month depending on the society size. This common area bill is shared equally among all flat owners, regardless of how much each flat actually benefits from those facilities.
Solar offers a direct solution. A rooftop solar system on the society’s terraces, sized to cover common area consumption, can reduce the common area bill by 60 to 80%, with a 4 to 6 year payback on the system investment. Several Indian states have now formalised group net metering or virtual net metering frameworks specifically for residential societies, cooperative housing societies, and apartment complexes.
This guide explains how group net metering works where it is allowed (Maharashtra, for example), what Gujarat societies can do under standard net metering, how to calculate the right system size, how to split the savings fairly among members, and what the actual costs and returns look like.
Key takeaway. A 50 kWp rooftop solar system for a 100-flat housing society in Ahmedabad costs ₹18–₹22 lakh installed and generates about 80,000 kWh a year, worth roughly ₹3.7–₹4.4 lakh at ₹4.65–₹5.50 per unit before fuel surcharge and duty, a payback of about 4 to 6 years before subsidy. If the society’s common-facilities connection qualifies for the PM Surya Ghar GHS/RWA rate of ₹18,000 per kW (₹9 lakh on 50 kW, with DCR modules), payback falls to roughly 2 to 3.5 years. Where the state allows group or virtual net metering (Maharashtra, for example; Gujarat’s regulations do not), society members can receive proportional credits on individual flat bills, a significant change from older models where savings only appeared on the common meter.
What Is Group Net Metering for Housing Societies?
Standard net metering works for one consumer, one meter, one solar system. Group net metering (also called virtual net metering or collective net metering) allows a solar system on a shared roof to distribute its generation credits across multiple consumer accounts.
In practice:
- The society installs solar panels on the common rooftop.
- The solar inverter connects to the society’s common area electricity connection (the “generator meter”).
- The DISCOM’s group net metering framework credits excess solar units to individual flat meters, according to a pre-agreed formula.
- Each flat owner sees reduced electricity bills proportional to their share.
Net metering is regulated by each state’s electricity regulatory commission, not by CERC (Central Electricity Regulatory Commission). Maharashtra’s MERC added group net metering in its 2023 amendment and virtual net metering in 2024; Karnataka (KERC order of July 2025) and Rajasthan (RERC amendment of October 2025) have followed. Gujarat’s GERC net metering regulations, as amended up to November 2025, do not provide for either.
Solar System Sizing for a Housing Society
The Heaven Green Society Solar Sizing Method follows a straightforward three-step process:
Step 1, Measure common area consumption. Pull 12 months of electricity bills for all common area meters: main building meter (lifts, corridor lights, pump motors), clubhouse meter, parking meter. Add them up. Your annual common area consumption is your target.
Step 2, Identify available rooftop area. The society’s flat terrace and common staircase terrace are the primary zones. For a G+10 apartment block with a 20 × 30 m rooftop, usable solar area after water tanks, mumty, and cooling tower clearance is typically 300 to 450 m². That accommodates roughly 30 to 45 kWp, using MNRE’s rule of thumb of about 10 m² of shade-free area per kW.
Step 3, Size to 80% of common area annual consumption. This ensures the solar system covers the bulk of common area bills without over-generating (which reduces financial efficiency under most DISCOM policies). Example: a society with annual common area consumption of 1,00,000 kWh should install a 50 kWp system (80% is 80,000 kWh, and 50 kW × 1,600 kWh/kWp/year = 80,000 kWh/year).
Step-by-Step: How to Get Solar for Your Housing Society
Getting a society solar system from idea to operation involves more stakeholders than a single-home installation. Here is the full process:
Sharing Solar Savings Among Society Members
This is where most societies hit internal disputes. There are three methods for distributing solar savings from a common area system:
| Method | How it works | Fairness | Complexity |
|---|---|---|---|
| Offset only common area bill | Savings stay on the society’s common area meter, reduce monthly maintenance contribution | Equal benefit to all flats | Simple; no DISCOM coordination |
| Pro-rata share by flat size | Common area savings split by carpet area among all flats; each flat’s individual bill gets a credit | Proportional benefit | Requires DISCOM virtual metering support |
| Equal share per flat | Savings divided equally, regardless of flat size | Simplest but ignores floor/size differences | Simple; may cause disputes in large-vs-small flat buildings |
Most Gujarat societies use “offset common area bill”, the simplest approach. The solar system reduces the common area electricity bill, which directly reduces the monthly maintenance charge for all members.
If your DISCOM supports virtual net metering (individual flat credit), the “pro-rata share by flat size” method is fairest and most motivating for member support at the GBR.
Cost Breakdown: 50 kWp Society Solar System
Installed cost for a 50 kWp rooftop solar on a G+10 residential society in Ahmedabad (Q2 2026):
| Component | Amount |
|---|---|
| Solar panels (540W TOPCon, 93 panels, ALMM-listed DCR) | ₹9,30,000 |
| 3-phase string inverter (50 kW) | ₹3,00,000 |
| Mounting structure (flat RCC roof) | ₹2,50,000 |
| DC/AC cables, earthing, ACDB/DCDB | ₹1,80,000 |
| Civil works, safety provisions | ₹80,000 |
| Installation labour | ₹1,00,000 |
| Net metering application and DISCOM coordination | ₹60,000 |
| Total installed (before subsidy) | ₹19,00,000 |
| PM Suryaghar GHS/RWA CFA (₹18,000 × 50 kW, if eligible) | −₹9,00,000 |
| Net installed cost | ~₹10,00,000 |
Note: The GHS/RWA subsidy depends on the connection being dedicated to common facilities, the society or RWA being the applicant, DCR modules and a portal-registered vendor. The cap is 3 kW per house (300 kW for 100 flats) and 500 kW overall, and it includes any rooftop plants residents have installed individually.
Curious what solar would cost for your society? Use our free solar calculator, savings estimate in 60 seconds.
Is Group Solar Worth It for Your Society: Pros and Cons
- 60 to 80% reduction in monthly maintenance charge (energy component)
- Simple approval process, one GBR resolution and one DISCOM application
- Increases property value for all flats in the complex
- No disruption to individual flat owners during installation
- 25-year panel warranty gives long-term energy cost certainty
- Requires GBR approval, can be delayed by member objections
- Rooftop access rights and waterproofing responsibility must be clear
- Virtual net metering (individual flat credit) not available in all DISCOMs
- Shared ownership requires clarity on maintenance responsibility
How Heaven Green Energy Supports Housing Societies
Heaven Green Energy has installed solar at housing societies in Ahmedabad, Surat, Rajkot, and Vadodara, and has experience with UGVCL and DGVCL net metering applications for society common connections. We handle the entire process from GBR documentation support to final DISCOM commissioning, and provide a detailed savings report to the society committee for member communication.
Our housing society solar service includes: pre-assessment and savings estimate, GBR resolution template, three-quote summary for committee, PM Suryaghar / DISCOM application, installation with waterproofing warranty, and 5-year AMC.
- Residential solar systems: individual flat solar for members who want their own rooftop system in addition to the common area installation.
- Commercial solar: for larger societies with clubhouse, parking, and gym loads exceeding 50 kW.
- Solar for new home construction: if your society is under construction, plan solar from day one.
- Net metering in India guide: full guide to how DISCOM net metering credits work.
- PM Suryaghar complete guide: subsidy eligibility and application process.
Frequently Asked Questions
Can a housing society apply for PM Suryaghar subsidy?
Yes. MNRE’s PM Surya Ghar guidelines give group housing societies and RWAs ₹18,000 per kW for common facilities, including EV charging, up to 500 kW at 3 kW per house. The connection must serve common facilities only, the modules must be DCR (Indian cells and modules), and a vendor registered on the national portal must do the installation. The cap includes any rooftop plants residents installed individually.
How much solar can a G+10 housing society install?
A G+10 society with a 20 × 30 m rooftop typically has 300 to 450 m² of usable solar area after water tanks and mumty clearance. This accommodates roughly 30 to 45 kWp, using MNRE’s rule of thumb of about 10 m² of shade-free area per kW. The ideal size is matched to the annual common area electricity consumption, typically 50 to 80 kWp for a 100-flat society in Gujarat, which usually needs the terraces of more than one block.
How does the society decide to go solar?
The managing committee typically presents the solar proposal to the general body. A GBR resolution passed by the required majority (varies by state and society registration act) authorises the committee to proceed with the installation and use society funds or a special levy. Heaven Green Energy provides a presentation-ready savings report and ROI summary for committee members to use at the GBR.
Can individual flat owners also install solar panels on the common terrace?
This depends on the society’s bylaws. Some societies allow individual flat owners (typically top-floor owners) to install panels on adjacent terrace areas for their individual benefit, while the society’s system uses the central terrace zone. This needs explicit committee approval and a written agreement on roof zone allocation, maintenance access, and waterproofing responsibility.
What happens if a member sells their flat, do they take the solar savings with them?
Solar savings are tied to the consumer connection (the society’s common area meter), not to individual flats. When a flat is sold, the new owner inherits the proportional reduction in maintenance charges that comes from the solar system, the same benefit the previous owner had. The solar system is a common area asset owned by the society, not by individual members.
Does solar work for a gated community with multiple towers?
Yes, and it’s often more cost-effective because there’s more pooled rooftop area and more common area load to offset. For a large gated community with 500+ flats across multiple towers, a 200 to 500 kWp solar system covering all common area consumption can reduce the monthly maintenance contribution’s energy component by roughly ₹250 to ₹700 per flat per month (at about ₹5 a unit across 500 flats). Where the state allows group net metering (Maharashtra does; Gujarat’s regulations do not), each tower’s common meter connection can be linked through it.
How does a society protect its roof warranty when installing solar?
Modern solar mounting systems on flat RCC roofs use concrete ballast mounting or L-foot bolted mounting with EPDM rubber pads, these do not penetrate the waterproofing membrane. Heaven Green Energy provides a 5-year leak-free warranty for all roof installations. The installation is done after the rainy season (October–February is ideal) and a pre-installation roof condition inspection is included. Any pre-existing leaks are documented before work begins.
What is the maintenance required for a housing society solar system?
Minimal. Quarterly panel cleaning (or after dust storms), annual electrical inspection of cable terminations, and periodic inverter firmware updates. Heaven Green Energy’s 5-year AMC covers all scheduled maintenance visits, panel washing, and one free corrective maintenance visit per year. The annual AMC cost for a 50 kWp system is ₹15,000–₹20,000, a fraction of the annual savings.