Price-sensitive quotes often lead with the modules. The panels can be a respectable brand. The saving, a few thousand rupees on the pitches we hear, is taken from the inverter: a white-label import with a basic compliance mark and no service desk you can visit. The array only produces while that inverter is synchronised with the grid. A dead inverter is a dark plant, whatever name is printed on the glass.
Who sold you the job is a separate check. The invoice, the bank account, and the PM Surya Ghar vendor still have to match. That test is in the vendor guide. This page is the hardware half: the brand inside the utility box, and the clause that says where a failed unit goes.
Why the panel brand is the easy part of the quote
Modules sit in the sun for decades. Their performance warranty, commonly 25 years, is a claim about the module, made through the seller on the invoice. The inverter works harder and the cover is shorter. It tracks the roof, syncs to KSEB voltage, and lives in a hot utility space through the monsoon. A quote that prints a famous panel and writes “inverter as per site” has hidden the part that stops the plant.
A BIS certificate means the model met the standard required to be sold. Plenty of budget inverters clear that bar. What the mark does not record is a spare board in Kerala, a person who will open the cover, or a company that will still answer in year five. Some imported brands sell through a shifting importer. When that importer stops, the number on the carton stops with them. That is a risk to price in now. It is not a forecast that every overseas factory will leave India.
Three ways a warranty actually works
Someone comes to the wall
A technician diagnoses the fault at the house or the plant and repairs or swaps the unit there. The visitor may be the brand’s engineer or the local partner authorised to do that swap. Sonetec’s doorstep service, for the Luminous and Microtek plants we sell, is this visit from our own engineers in the four districts. Factory engineers back the brand warranty. The card for that serial says how many years, and what they will replace.
Someone talks you through it
A remote technician, often in another city, guides the local installer through error codes and settings on a call. That clears a software fault. A failed power stage still needs a part and a person at the wall. A brand with a phone line and no district visit sits in this middle.
The unit leaves the site
The manufacturer sends nobody. The installer unbolts the inverter, packs it, and ships it to a depot. Generation stops until that unit returns or another is fitted. Freight, labour, and the weeks in transit belong on the quotation. If the company behind the card has closed its Indian desk, the depot address may no longer answer.
What each clause does to the plant
| What to compare | Visit at the wall | Phone guidance | Ship to a depot |
|---|---|---|---|
| Who travels | A technician comes to the inverter. | Your installer follows a remote engineer. | The inverter travels. Nobody from the brand does. |
| While you wait | Downtime is the repair visit, or the time to a swap if the card allows one. | A settings fault can be the same day. A dead board is not. | The string is down for the courier and the depot queue unless a replacement is fitted first. |
| On the quote | Brand, model, years, and who attends in your district. | The helpline, and who still comes if the call cannot fix it. | Who unbolts it, who pays freight, and what runs the plant meanwhile. |
Inverter years are the brand’s term for that model. Luminous on-grid models we publish list an extended warranty backed by Luminous factory service and Sonetec on-site support. The card on your serial is the term that applies. Module performance cover, often 25 to 30 years, is a different document. A few thousand rupees off the quote is not proof the inverter is poor. A missing model name is.
Four checks before you accept the quote
- Name the inverter, not only the panels. Brand, model series, and data sheet on the quotation. “As per site” and “equivalent” are how a budget unit arrives after you have agreed a panel brand.
- Read the year-3 sentence. If this inverter fails, who comes, does the unit leave the wall, who pays labour and freight, and does anything generate while it is gone? On-site replacement is a clause you can read. It is not a mood.
- Find the Indian desk. A regional service point and a helpline that belongs to the brand, not only the importer who sold this container. Then ask who in Kollam, Thiruvananthapuram, Pathanamthitta, or Alappuzha actually visits.
- Match the name on the card to the name on the invoice. The company that will raise the claim should be the company you paid. A panel warranty and an inverter warranty are two cards. Keep both with the serials.
What Sonetec puts on the wall
We quote Luminous or Microtek where that inverter fits the load, and we install in South Kerala. The brand is on the quotation and the invoice. Our engineers attend from Chathannoor, Anchal, and Chadayamangalam. For the Luminous and Microtek plants we sell, that attendance is doorstep service in the four districts, with the manufacturer’s warranty card for that serial. We do not describe a depot shipment as a visit. If a model’s card says the unit must be sent away, that line belongs on the quote before you pay.
The same offices do the rest of the plant: chemical anchors, a DC earth and a separate AC earth in at least 10 SWG copper, surge protection, and a lightning arrestor. Those details are on the Kerala subsidy page. Plants we did not install can still be diagnosed in these four districts. That work is the maintenance visit, priced on its own, and it does not create a manufacturer warranty the brand never issued.
Questions before the inverter is a surprise
Does a BIS certificate mean the inverter will be serviced in Kerala?
What should the quotation say besides the panel brand?
What happens under an offsite warranty?
Which inverters does Sonetec name on a South Kerala quote?
Put the inverter brand on the survey
Free roof survey in Kollam, Thiruvananthapuram, Pathanamthitta, and Alappuzha. We name the model, and we service what we install.
BIS certification is a product-entry mark, not a service promise. Inverter warranty terms are the manufacturer’s card for that serial. Sonetec attends Luminous and Microtek plants we sold, from offices in Chathannoor, Anchal, and Chadayamangalam, across South Kerala. Module performance warranties are separate.