Frequently Asked Questions
Economics & Costs
Is It Worth To Buy Solar Power Plant For Homes?
Unlike TV, car, home theaters, etc, SOLAR POWER PLANT on your roof saves your electricity bill month on month and it is like a Fixed deposit giving consistent returns.
Why invest in a solar PV system when 100 units are free and tariffs are low?
Yes 100 units are free in tamil nadu, and the tariffs are low only upto 500 units after which it shoots gradually upto Rs. 11.55 per unit
What is the cost of installing a rooftop solar PV system?
The average cost ranges from ₹60,000 to ₹75,000 per kilowatt (kW), depending on system capacity, structural modifications and site conditions.
What subsidies are available, and how long does it take to receive the money?
For 1kW – Rs. 30,000 for 2kW – Rs. 60,000 for 3kW and above – Rs. 78,000. Subsidy money is reimbursed to the beneficiary bank account directly within 15 days of net meter installation.
How much can I save on electricity bills with solar?
A 2 kW system can save upto ₹12,000 annually. 3 kW system can save upto ₹24,000 annually. Larger systems save proportionally more.
What is the return on investment (ROI) period?
Typically, the payback period is 4–6 years after considering electricity savings.
What fees are paid to the electricity board?
You need to pay only for the net meter, single phase Rs.2,780 & 3 phase Rs. 4,720 in Tamil Nadu.
Can solar PV help in getting a green building rating certification?
Yes, installing solar PV contributes to points in green certifications like GRIHA and LEED, making it easier to obtain eco-building recognition.
Is a new EB meter required? What are the types?
Yes. A bi-directional/net meter is required for grid-connected systems to measure electricity export and import.
Are loans or EMI options available? What are the interest rates?
Yes, loans are available from nationalized banks and NBFCs. Interest rates 6% onwards.
What is the applicable GST for solar PV systems?
Solar PV systems attract a 8.9% GST rate (as of current regulations).
Is subsidy available for both residential and commercial consumers?
Yes. Solar will reduce your bill drastically. Only the network charges to be paid.
Is subsidy available for both residential and commercial consumers?
Currently, subsidy is mainly available for residential users & apartments.
Is subsidy applicable for apartments?
Yes, available for the residence and also for the common amenities under Residents’ welfare association.
How do I apply for a rooftop solar subsidy?
Subsidies can be applied through VESAT – an MNRE empaneled vendor in the National Portal.
Technology & Performance
How much energy can a solar PV system generate?
A 1 kW system typically generates about 4–5 units (kWh) of electricity per day, depending on location and sunlight availability.
How do I determine the right capacity for my home?
Based on your average monthly electricity usage. Roughly, 1 kW is suitable for 100–120 units of monthly consumption.
What are the different types of solar PV systems?
- On-grid: Connected to the grid, no battery.
- Off-grid: Battery-based, used in remote areas.
- Hybrid: Combines grid and battery for backup.
What types of solar PV panels are available in the market?
- Monocrystalline: Higher efficiency, space-saving.
- Polycrystalline: More affordable, slightly lower efficiency.
- Thin-film: Flexible, less common for rooftops.
How much space is required for installation?
Approximately 70 sq. for 1 kW of panel capacity.
What are the key components of a solar PV system?
- Solar panels
- Inverter
- Mounting structures
- Net meter
- Batteries (optional)
- Wiring & protection systems
What is the ideal orientation for solar panel installation?
South-facing with a tilt angle equal to the location’s latitude gives best performance in India.
Will panel efficiency be affected by climatic conditions?
Yes! Dust, heat, cloud cover, and humidity can reduce efficiency slightly. Proper maintenance minimizes impact.
Will a nearby tree or shading affect performance?
Yes. Even partial shading can significantly reduce energy generation. Avoid shaded areas when installing panels.
Can solar panels work in polluted areas?
Yes, but pollution can settle as dust on panels and reduce efficiency. Frequent cleaning is needed.
Do bird droppings impact efficiency?
Yes. They can block sunlight and reduce output. Regular cleaning is advised.
Does solar work well in coastal areas with salt exposure?
Yes, if components are corrosion-resistant. Use marine-grade mounting structures.
Can it withstand cyclones and strong winds in Chennai?
Yes, if installed with proper wind-load-rated structures and mounting systems.
How can I monitor if my system is working properly?
Most systems have a mobile app or online portal provided by the inverter company to monitor real-time performance.
What maintenance is required, and how often?
- Clean panels every 1–2 weeks.
- Professional check-up every 6–12 months.
What testing is needed during maintenance?
- Panel output check
- Inverter function check
- Wiring & safety checks
- Mounting and alignment inspection
What is the lifespan of a solar PV system?
- Solar panels: 25 years
- Inverters: 8–12 years (may need replacement once)
How does aging affect performance?
Panels degrade over time. Most lose 0.5–0.8% efficiency per year, retaining around 80–85% performance after 25 years.
Can panels be reused after their lifetime?
Yes, for low-power applications, though with reduced efficiency.
How should solar panels be transported safely?
Use original packaging, avoid stacking, transport vertically with padding, and handle with care.
Is there a proper procedure for solar panel disposal?
Yes. Follow e-waste disposal rules and hand them over to authorized recyclers.
What are the environmental benefits of solar PV?
- Reduces carbon footprint
- Decreases fossil fuel use
- Cuts air pollution
- Promotes clean, renewable energy
Installation & Usage
How much time is required for installation?
Installation usually takes 1 to 3 days, depending on the system size and complexity of the site.
Can I install solar without drilling my roof?
Yes. For flat roofs, non-penetrative mounting structures with ballasts or clamps can be used. For sloped roofs, minimal drilling may be necessary.
I live in an apartment. Can I install solar panels on the rooftop or balcony?
Yes, with the consent of the apartment association and availability of rooftop or balcony space. Shared systems are possible for common areas.
Can I install solar PV in a rented house? What happens if I relocate?
Yes, with the landlord’s permission. If you relocate, the system can be uninstalled and moved, though it may involve additional cost and reinstallation effort.
What is shared ownership and usage of solar in apartments?
It allows multiple residents to jointly install and use a solar system. The generated power is used for common areas or split among users based on agreed terms.
What are the different appliances that can be connected to a solar PV system?
You can power lights, fans, TVs, refrigerators, laptops, and other low to medium-load appliances. For high-load devices like ACs, pumps, or heaters, ensure the system is properly sized.
If a house has multiple service connections (e.g., G+3), how will billing and metering be managed?
Separate net meters can be installed for each service connection, or a single point connection can be used with proper load sharing and approval from the electricity board.
How do I choose a reliable vendor for installation?
Yes, installing solar PV contributes to points in green certifications like GRIHA and LEED, making it easier to obtain eco-building recognition.
What parameters should I consider while selecting a vendor?
- Experience and past installations
- Certification and empanelment
- Component quality (panels, inverter)
- Service warranty
- Customer reviews
Where can I get details of vendors and installers?
Details are available on the MNRE website, National Rooftop Solar Portal (https://solarrooftop.gov.in), and TEDA website for Tamil Nadu.
How much time is required for installation?
Installation usually takes 1 to 3 days, depending on the system size and complexity of the site.
Storage & Backup Power
Are batteries necessary for a rooftop solar PV system?
Not always. On-grid systems do not require batteries, as they draw power from the grid when solar is unavailable. Batteries are used in off-grid or hybrid systems for backup.
Can power backup inverter batteries be used as solar storage batteries?
Yes, but only if they are compatible with solar charging and configured correctly. It’s best done with the help of a solar professional.
Can my existing UPS be connected to a solar PV system?
Yes, with proper integration by a qualified installer. You may need a hybrid inverter to manage both solar and grid input effectively.
How will I get power at night?
In on-grid systems, power is drawn from the grid at night. In off-grid or hybrid systems, power comes from the battery charged during the day.
Can my solar PV system supply power during outages?
- On-grid systems automatically shut down during outages for safety (anti-islanding).
- Hybrid or off-grid systems can supply power from the battery during outages.
My area has voltage fluctuations. Will this affect my solar PV system?
Yes, installing solar PV contributes to points in green certifications like GRIHA and LEED, making it easier to obtain eco-building recognition.
Will water clogging on the roof affect solar panels?
Yes. Water stagnation can damage mounting structures, cause leakage, and reduce panel performance. Ensure proper roof drainage during installation.
Policy & Future Concerns
If DISCOM removes net metering or subsidies in the future, will it impact my investment?
Not significantly. Your system will continue to generate power and reduce bills. However, return on investment (ROI) may take longer for new installations if subsidies/net metering are removed. Existing users are usually protected under the scheme active during installation.
What are the latest advancements in solar technology?
- Bifacial panels (capture sunlight from both sides)
- High-efficiency monocrystalline panels
- Smart inverters with monitoring apps
- Energy storage integration (Li-ion batteries)
- Floating solar systems and transparent solar panels (in R&D stage)
Is there insurance available for panel damage?
Yes. Many insurers offer solar-specific insurance that covers damage from fire, theft, natural calamities, or system failure. It’s recommended for commercial and large residential systems.
Will installing solar PV increase heat inside my home?
No. In fact, panels provide shade and may help in reducing roof temperature, especially on flat-roof installations.
Is it safe to touch solar panels while they’re operating?
Yes, panels themselves are safe to touch, but you should avoid contact with wires, terminals, or wet panels during operation to prevent electric shock.
Can my solar system pose a shock risk to linemen during grid outages?
Yes, if not properly installed. On-grid systems must have anti-islanding protection, which automatically shuts down the system during outages to protect utility workers.
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