How to Choose a Rooftop Solar Installer: Checklist
A practical checklist to choose a rooftop solar installer in India: registration, quote line items, structure, earthing, warranties, service and red flags.
Short answer: pick an installer who is a registered vendor for your DISCOM, gives an itemised quote (exact makes and models, structure, earthing, cable sizes), can show local completed jobs, handles net metering and the subsidy portal, and commits in writing to 5-year maintenance and clear warranty support. Compare quotes on the same specification, not just the price.
1. Registration and paperwork
- [ ] Registered vendor for your DISCOM on pmsuryaghar.gov.in (needed for subsidy)
- [ ] GST registration and a proper tax invoice
- [ ] Electrical contractor licence as required in your state (ask which)
- [ ] A written agreement covering scope, price, payment stages, timeline and service
2. The quote: every line should be specific
| Item | What to ask for | Red flag |
|---|---|---|
| Modules | Make, model, Wp, TOPCon/PERC, DCR certificate | "Tier-1 panels" with no model |
| Inverter | Make, model, kW, phase, warranty years, monitoring | "Branded inverter" with no model |
| Structure | Material (HDG or pre-galvanised), coating in microns, height, anchoring method, wind design basis | No height or coating mentioned |
| DC cable | Size (4 or 6 sq mm), solar-rated to EN 50618 / IS 17293 | "Copper wire" only |
| AC cable | Size, copper/aluminium, armoured or not | No size |
| DCDB | DC isolator, DC SPD, fuses if 3+ strings in parallel | No SPD |
| ACDB | MCB/MCCB, RCCB, AC SPD, isolator | Only an MCB |
| Earthing | Number of pits (usually DC, AC, LA), type, conductor size | One pit for everything |
| Lightning arrester | Type, mast height, down conductor size | "LA included" only |
| Net metering | Who applies, who pays fees | Left to you |
| Service | 5-year maintenance terms, response time | Verbal promises |
3. Structure: the part that holds 25 years
Ask how the structure will be fixed to your roof and how leaks will be prevented.
- On thin house slabs (100–125 mm), chemical anchors are safer than mechanical expansion bolts, which can crack the slab.
- Hot-dip galvanised steel (around 80 microns) resists rust far better than painted mild steel.
- Coastal and high-wind areas need heavier sections and a design check against IS 875 (Part 3). See structure design and wind.
- In Maharashtra and Karnataka, an elevated structure (front legs about 1 m) keeps your terrace usable.
4. Earthing and lightning: do not compromise
A good installer will plan separate earth pits for the array frames (DC), the inverter and ACDB (AC), and the lightning arrester, at least about 3 m apart. The lightning down conductor should meet the minimum sizes in IS/IEC 62305 rather than a thin wire. Ask what earth resistance they will test and record. Details: earthing and lightning for rooftop solar.
5. Design: ask to see it
A professional installer will show you:
- A layout on your roof with module positions and walkways
- A shade check (morning and afternoon, especially December)
- String design matched to the inverter's voltage window
- Expected yearly generation and the assumptions behind it
- A single-line diagram (SLD), needed for net metering in many DISCOMs
If the generation estimate looks too good (for example more than 1,700 units per kW per year in most of India), ask how it was calculated.
6. Warranties and service
| Item | Typical warranty |
|---|---|
| Module product | 10–15 years |
| Module performance | 25–30 years, with stated output at the end |
| Inverter | 5–10 years (extendable on some models) |
| Structure | ask; good installers give 5+ years against rust |
| Workmanship and maintenance | 5 years under PM Surya Ghar (check current notification) |
Ask who handles a warranty claim: the installer, the distributor or the manufacturer. Installers buying from a distributor with an RMA desk (return and replacement handling) usually get faster replacements.
7. Visit or call past customers
Ask for two or three local customers whose systems are at least a year old. Ask about generation, any leaks, response time to faults and how net metering went.
Red flags
- Pressure to sign the same day, or a "subsidy guaranteed" promise
- No itemised quote, or vague brands
- Advice to install a much bigger system "to sell power"
- Asking you to install before the portal application
- Full payment upfront
Questions to ask on the first call
- Are you registered for my DISCOM on the PM Surya Ghar portal?
- Which module and inverter models will you use, and why?
- How will you fix the structure and stop leaks?
- How many earth pits, and what size lightning down conductor?
- Who does net metering, and how long does it take here?
- What does the 5-year maintenance include?
Get sizing right first: 200 units, 300 units, 500 units. And understand what solar costs per kW.
What a fair payment schedule looks like
Payment terms vary, but a balanced schedule protects both sides:
- Advance on signing, enough for the installer to book material
- Material delivery payment when modules and inverter reach your site
- Balance after installation and commissioning, or after the net meter is fitted
Avoid paying 100% upfront. Get every payment receipted against the agreement.
Talk to Sunlectric
Sunlectric is a distributor, so we work with many installers across Maharashtra and beyond. WhatsApp +91 89567 89307 (wa.me/918956789307) with your PIN code and we will connect you with a registered installer who buys genuine, documented material from us. You can also send us a quote you already have and we will check the specification.
Sources
- PM Surya Ghar vendor registration and 5-year maintenance: pmsuryaghar.gov.in; PIB guidelines, Aug 2024 (accessed Oct 2026)
- Standards referenced: IS 875 (Part 3):2015 wind loads; IS 3043:2018 earthing; IS/IEC 62305 lightning protection; EN 50618 / IS 17293 PV cables (check current editions)
- Sunlectric Studio engineering rules and review, Oct 2026 (anchors, earthing pits, structure)
Questions people ask
How do I know if a solar installer is genuine?
Check that they are a registered vendor for your DISCOM on the PM Surya Ghar portal, have GST registration, can show completed local jobs you can visit, and give an itemised written quote with makes, models and warranties.
What should a solar quotation include?
Module make, model, wattage and DCR status; inverter make and model; structure material, coating and height; cable sizes; earthing pits and lightning arrester; DCDB/ACDB contents; net-metering work; service terms and warranties.
Is the cheapest quote a bad idea?
Not always, but low quotes often cut structure steel, earthing, surge protection or cable size. Compare the same specification line by line before comparing totals.
Who maintains the system after installation?
Under PM Surya Ghar the vendor provides five years of comprehensive maintenance. Ask what that covers, how fast they respond, and who honours the inverter and module warranties.