Common Mistakes Homeowners Make Before Installing Solar (India)

Rooftop solar can cut your electricity bill for 20–25 years — but most “bad solar experiences” come from mistakes made before the first panel is installed. Here are the most common ones I see in Indian homes, and how to avoid them.

 

1) Choosing system size based on roof area (instead of your bill + load profile)

Mistake: “My roof can fit 3 kW, so I’ll do 3 kW.”

Do this instead:

• Pull 12 months of electricity bills (units + ₹).
• Note daytime usage (WFH, AC timings, water pump, fridge, etc.).
• Size solar to offset useful consumption under your local metering rules (net/gross/net billing varies by state).

Quick rule: If most of your usage is at night and you’re on-grid, a bigger plant won’t “magically” reduce the bill unless your daytime export credits are good in your state.

2) Not doing a proper shadow analysis (and trusting “it looks sunny”)

Mistake: Ignoring shadows from overhead tanks, parapet walls, neighboring buildings, trees, or future construction.

Why it hurts: Even partial shade can drop generation significantly (and it often shows up as “my solar isn’t working properly”).

Fix:

• Ask for a shade report (morning + noon + evening).
• Avoid placing panels near shadow-casting objects; consider optimizers only if unavoidable.

3) Not checking roof health and waterproofing before mounting

Mistake: Installing on an old/weak slab, cracked waterproofing, or loose tiles — then dealing with leaks in the first monsoon.

Fix:

• Do waterproofing/repairs first, then mount.
• Confirm the mounting method (chemical anchors vs. structure blocks) and warranty coverage for roof damage.

4) Picking the cheapest quote without comparing the full BOM

Mistake: Comparing only “₹/kW” and ignoring what’s inside:

• module brand/model
• inverter make/model
• mounting structure material/thickness
• DC/AC cables (brand + size)
• earthing, lightning protection, SPDs
• monitoring system
• workmanship + safety practices

Tip: Ask every vendor for the BOM in writing (with model numbers).

5) Not verifying module quality requirements (BIS + ALMM)

If you’re applying under government programs/approved procurement routes, equipment compliance matters.

What to check:

• BIS/CRS compliance & updated standards transition for PV modules (standards are evolving; good vendors should be aware).
• MNRE ALMM listing for PV modules where applicable.

This isn’t just “paperwork” — it often correlates with traceability and after-sales accountability.

6) Ignoring your DISCOM rules and metering type (net vs gross vs net billing)

Mistake: Assuming net metering is the same everywhere.

Reality: Policies differ by state, DISCOM, and consumer category — and they can change.

Do this:

• Confirm your approved capacity limit, settlement cycle, and export compensation.
• Ask the vendor who handles DISCOM paperwork and timelines.

7) Applying for subsidy after installation (wrong order)

Mistake: Installing first, then asking “how to get subsidy?”

If you’re using the PM Surya Ghar route, follow the official portal/application flow.

• Official portal: PMSuryaghar
• Scheme guidelines and timelines: MPEZ

 8) Misunderstanding PM Surya Ghar subsidy and expectations

Mistake: Thinking subsidy is unlimited or applies beyond the designed cap.

As per scheme guidelines, the CFA structure is tied to benchmark cost and capped (no subsidy beyond the specified capacity).

Also, the program includes a 5-year comprehensive maintenance obligation in the model agreement/CMC provisions — so you should insist your contract matches that.

9) Buying a battery because “solar means backup”

Mistake: Assuming on-grid solar will run your home during a power cut.

Truth: Standard on-grid systems shut down during outages (anti-islanding). Backup needs hybrid + battery (or separate backup inverter architecture).

So decide clearly:

• Bill reduction priority → on-grid
• Backup priority → hybrid + battery (higher cost, battery replacement planning)

10) Wrong inverter selection (and ignoring service network)

Mistake: Choosing inverter by kW rating only.

Check:

• single-phase vs three-phase compatibility
• MPPT count vs panel string design
• voltage window suitability
• warranty + local service response time
• monitoring/app reliability

A good inverter with poor service support can become your biggest headache.

11) Skipping electrical safety: earthing, SPDs, isolators, cable sizing

Mistake: “It’s just a small system, safety isn’t a big deal.”

Minimum you should ask for:

• DC & AC isolators
• surge protection devices (SPDs)
• proper earthing (separate for LA if used)
• correct cable size (low voltage drop)
• neat trunking/conduits + labeled breakers

This is the difference between “runs for years” and “random failures every summer.”

12) Not planning for panel cleaning and access

Mistake: Installing panels where nobody can safely reach them.

Dust + bird droppings can visibly reduce generation. Plan:

• safe access path
• water point/cleaning arrangement
• cleaning frequency (more in dusty zones)

13) Not demanding monitoring and a basic generation benchmark

Mistake: No monitoring app, no idea what “good generation” looks like.

Fix:

• Ensure monitoring is included and activated.
• Ask for a realistic monthly generation range (kWh) based on your city + orientation.

14) Signing a vague contract (warranties, service, delays, exclusions)

Mistake: Paying a big advance with unclear terms.

Your contract should clearly state:

• model numbers (modules/inverter)
• total scope (net meter application, approvals, structure, cabling, protections)
• timeline with milestones
• workmanship warranty
• shutdown/low-generation support process
• O&M/CMC terms (especially if under PM Surya Ghar)

15) Forgetting future loads (EV, extra AC, heat pump, induction cooking)

Mistake: Sizing only for today.

If you’re likely to add:

• EV charger
• another AC
• larger pump
• home office expansion

…tell your installer now. It may change inverter choice, DB planning, and wiring.

 

A simple “Before You Install Solar” checklist

• 12 months bills reviewed + daytime load mapped
• Shade analysis done (photos/videos morning–evening)
• Roof waterproofing/health checked
• DISCOM metering type + capacity rules confirmed
• Portal/subsidy steps followed in correct order
• Module compliance verified (BIS/CRS + ALMM as applicable)
• Inverter specs + service support validated
• Safety items included: isolators, SPDs, earthing, correct cable size
• Monitoring included + benchmark shared
• Written BOM + clear contract + milestone payments

Want to run the numbers for your own home?
I’ve put together a simple step-by-step guide + an Excel Solar PV Design Calculator to help you estimate system size (kW), 1st-year generation (kWh/year), savings, and payback.
Read it here: Solar PV System Design Calculator (Excel)

External references (useful)

• PM Surya Ghar official portal and subsidy details
• PM Surya Ghar CFA guidelines (official)
• MNRE ALMM information
• Detailed information on PM Surya Ghar Yojna