Key takeaways
- Judge a 25-year rooftop system by its wiring, structure and protection devices as well as its panels; these balance-of-system parts account for many early faults.
- A home system needs a registered PM Surya Ghar vendor and eligible DCR modules to claim the subsidy, which is capped at ₹78,000 for 3 kW and above.
- Ask for an itemised Bill of Materials that names cable sizes, switchgear ratings, structure thickness and earthing details.
- Link each payment to a completed stage. A sample schedule holds the final 10% until the DISCOM net meter is working.
Your rooftop system must keep producing through strong sun, monsoon rain, wind and daily temperature changes for 25 to 30 years. The panel price alone cannot tell you whether the complete plant will do that. Start with the full quotation, including the parts and work that sit between the modules and your meter.
Suppose two installers both propose 5 kW and one price is ₹35,000 lower. Check what creates the gap. The cheaper scope may specify thin sheet metal supports, ordinary AC wire in place of UV-resistant solar DC cable, fewer surge protection devices or no chemical earthing pits. Ask each bidder to account for those items in writing.
A weak connection may show up as low output or repeated inverter trips only after commissioning. A missing approval can delay the net meter even when the panels are already on your roof. Use the following 12 questions to test the installer, the engineering and the contract before you pay a deposit.
Why installation quality affects solar output
TOPCon and Mono PERC are useful panel choices to compare, but the rest of the design matters just as much. A panel with a 30-year performance warranty cannot deliver the region's approximate annual average of 4 to 4.5 units per kW per day if the string layout is wrong, the cables lose too much voltage or the inverter is undersized.
Ask who designs the roof supports for a 150 km/h wind rating, who checks the DC circuits for electrical safety and who follows up with the distribution utility. These jobs need to come together on the same site. Their quality affects both the energy you collect and the time it takes to commission the system.
Check the company and its approvals
1. Is the vendor registered for PM Surya Ghar?
For a home claiming PM Surya Ghar assistance, check the installer's vendor ID on pmsuryaghar.gov.in before paying. The current amounts are ₹30,000 at 1 kW, ₹60,000 at 2 kW and up to ₹78,000 at 3 kW or more. A registered vendor must submit the commissioning record needed for the subsidy to reach your bank account; an unlisted electrician cannot complete that step.
2. Where can you reach the company after installation?
Ask how long the firm has worked locally, where its registered office is and which technicians handle faults in your area. Also check whether it keeps replacement parts nearby. Online sellers may pass installation to short-term crews, so establish who will return to your roof. Ray2Volt has its registered office in Srikalahasti and branches in Tirupati, Nagari and Puttur. Our Tirupati service page explains the area we cover.
3. Who takes the net-metering application through DISCOM?
Panels can be mounted in two to three days, while grid approval may take longer. Confirm that the written scope includes technical feasibility, the bi-directional meter, DISCOM inspection and electrical clearances. Ask for one named contact who will follow the application through to grid synchronisation.
Ask for the design and equipment list
4. Which panel and inverter models will be delivered?
A quote that says only "5 kW Tier-1 panels" leaves too much open. Ask for a line-by-line Bill of Materials with each maker, model, module wattage, cell type and inverter efficiency. Keep that list with the contract so you can match the equipment delivered against what you paid for.
5. Do the proposed modules meet DCR and ALMM rules?
PM Surya Ghar home systems need Domestic Content Requirement (DCR) modules, with Indian-made cells and modules, and the applicable MNRE ALMM listing. After the June 2026 List-II shift, Ray2Volt also prepares new commercial and industrial quotes with DCR panels unless an exemption is verified. Request the exact module datasheet, flash test report and RFID details rather than relying on a verbal assurance.
The PM Surya Ghar implementation period runs to 31 March 2027. For a residential system of 3 kW or more, central assistance is capped at ₹78,000. Non-DCR modules and unapproved imports do not qualify; confirm the current rules and your eligibility on the official portal.
6. What are the mounting structure and wind rating?
South Indian roofs can face strong gusts in cyclones and summer squalls. Ask to see the structure drawing and the basis for its 150 km/h wind rating. The proposal should specify hot-dip galvanised iron with an 80+ micron zinc coating or suitable structural aluminium. Compare that specification with a thin pre-galvanised pipe carrying only about 15 microns of coating; corrosion risk is different.
7. How will the installer protect the DC and AC circuits?
Have the installer mark the cable routes and protection devices on the drawing. Look for UV-resistant, XLPO-insulated tinned copper solar DC cable; chemical earthing pits with copper-bonded electrodes for the DC array, inverter AC side and lightning system; and Type-II surge protection devices in both distribution boxes. These details matter because poor DC connections and missing protection can cause faults and unsafe shutdowns.
Check warranties and local service
8. Who will handle a warranty claim at your site?
Keep the separate warranty terms clear: Ray2Volt quotes 12 years for panel product defects, 30 years for panel performance, 8 to 10 years for inverters depending on model, and 5 years of free service for workmanship and balance of system. Our guide to solar warranty cover explains the differences. Ask whether the installer diagnoses the fault and files the claim, or expects you to ship equipment to a service centre.
9. What response time will be written into the service terms?
If your inverter stops, generation stops with it. A 10 kW plant might produce about 40 to 45 units on a clear summer day, so delay has a measurable cost. Ask for a written service level agreement with a 24 to 48 hour response window, a local technician and a clear route for escalating unresolved faults.
10. Will you be able to see daily generation?
Many inverters send generation data over Wi-Fi or 4G to a phone app. Have the installer connect your account during handover and show you the daily units, alerts and error history. You should be able to spot a silent shutdown without waiting for the next electricity bill.
Read the price and payment terms
11. Which charges are included in the turnkey price?
Have the bidder identify crane or lifting charges, bi-directional meter testing, DISCOM application fees, calibration, freight and commissioning. A lower headline price can become expensive if these appear later. The signed quote should say which approvals and statutory charges the installer will manage and pay.
12. When is each payment due?
Do not pay the whole contract price in advance. Agree on amounts tied to visible progress, starting with design and ending with the working net meter. Put the trigger for each payment in the contract so there is no dispute at handover.
Sample payment stages: Pay 20% at booking and design, 60% when the specified materials reach your site, 10% after physical installation and the final 10% once DISCOM net-meter synchronisation succeeds. Confirm the stages in your own agreement.
What different installer quotes may include
Use the same checklist for every bidder. The table shows common differences in site assessment, equipment, DISCOM work and support. Treat these as points to verify in the actual proposal rather than assumptions about a company.
| What to compare | Low-cost contractor | Online aggregator | Full-service solar EPC |
|---|---|---|---|
| Roof assessment | May rely on a brief visual check. | May estimate from satellite images. | Site power audit with 3D shade review. |
| Panel supply | Check certification of the offered stock. | Confirm who supplies the modules. | Specified ALMM DCR modules with 30-year performance cover. |
| Roof supports | Thin pre-galvanised steel, about 15 microns. | Standard modular support kits. | HDGI with 80+ micron coating and 150 km/h wind design. |
| Electrical protection | Check whether ordinary AC wire is used on DC circuits. | Standard parts need model-level review. | Solar DC cable, three chemical pits and Type-II surge devices. |
| Grid approval | Homeowner may handle the application. | Paperwork may be managed remotely. | Feasibility, testing and net meter connection included. |
| Fault support | Check for a named local contact. | Support may start through a call centre. | Local team, proposed 24 to 48 hour response and monitoring. |
Six signs to question a solar proposal
Pause before signing if the installer cannot answer any of the points below. Request the missing document or compare another written proposal.
Check the promise: Full advance payment, unnamed cable brands and a claim of "zero electricity bills forever" without a load audit all call for closer scrutiny. Ask for a revised written scope before you commit.
- Full payment before work starts: Ask why the contract has no stages linked to delivered materials, installation and grid connection.
- Missing model details: A quote without exact modules and switchgear lets the supplied components change later.
- Output that exceeds local expectations: Use about 4 to 4.5 units per kW per day on an annual average, or roughly 1,400 to 1,600 units per kW yearly, as a first check. Ask for evidence if a quote assumes more than 6 units daily.
- No nearby systems to inspect: Request references for operating installations in your district and ask about service after handover.
- No office you can visit: Verify a physical address and a reliable way to reach the service team if a fault appears.
- No signed workmanship cover: Get written terms for roof waterproofing, structure and electrical installation.
Start your comparison with a roof and bill assessment using our guide to sizing a solar system. For local weather and DISCOM steps, read our Tirupati and Srikalahasti solar guide. If your priority includes power during grid outages, compare hybrid systems for homes with the options in our residential solar range.
All subsidy amounts and savings estimates here are indicative. Scheme rules can change, so confirm your own eligibility on the official portal and with the installer. Ray2Volt does not give tax or investment advice.
Questions about choosing an installer
Can an unregistered electrician install a subsidy-eligible home system?
No. A PM Surya Ghar home system needs a vendor registered on pmsuryaghar.gov.in and approved DCR modules. The vendor submits the commissioning report that starts subsidy processing. The current cap is ₹78,000 for 3 kW and above; confirm your eligibility before ordering.
Why can two quotes for the same capacity differ by ₹20,000 to ₹50,000?
Compare the structure gauge, switchgear, solar DC cable, net-metering charges and service terms. A lower figure may omit fees or specify cheaper balance-of-system parts. Ask both bidders for an itemised list before judging the price.
Who handles warranties if the original installer closes?
Manufacturer cover can still apply if you keep the invoice, serial numbers and commissioning papers. Panel performance cover lasts 30 years and inverter cover lasts 8 to 10 years, depending on model. You may need another qualified local firm to diagnose faults and help file claims.
When should the final payment be released?
Agree the stages before work begins. One sample split is 20% at booking and design, 60% when materials arrive, 10% after installation and the last 10% when DISCOM net-meter synchronisation is complete. Put the amounts and evidence for each stage in your contract.
How can you check the delivered panels against the approved list?
Match each module's RFID or serial details with its manufacturer flash test sheet, including the date, rated wattage and cell origin. Then check the exact model against the applicable MNRE ALMM list. Keep copies with your handover documents.
Ray2Volt Solar Private Limited
We design, install, and service rooftop solar for homes and businesses across Tirupati district and Andhra Pradesh, from PM Surya Ghar residential systems to commercial and industrial plants. Every enquiry starts with a free power audit.
Get a rooftop quote you can check line by line
Ray2Volt can assess your roof and bill, specify DCR modules and mounting hardware, and include DISCOM net-metering work in a written proposal for your Tirupati district site.
