Frequently Asked Questions

A rooftop solar power plant is a system that converts sunlight into electrical energy using photovoltaic (PV) solar panels. The generated DC electricity is converted to usable AC electricity through an inverter. This electricity directly powers your home or business, reducing or eliminating your KSEB electricity bill. Surplus electricity can be exported to the KSEB grid and credited against your consumption (net metering).

In Kerala's climate, a well-installed solar system generates approximately 4 units (kWh) per kW per day on average annually. This accounts for seasonal variation, monsoon cloudiness and panel orientation. So a 3 kW system generates ~12 units/day, ~360 units/month and ~4,380 units/year. This production figure is used by KSEB and MNRE for official capacity calculations.

Each kW of solar requires approximately 80–100 sq ft (7.5–9.3 sq meters) of shadow-free roof area. So a 3 kW system needs about 250–300 sq ft of usable roof space. For an accurate assessment, our engineers will visit your site and measure usable shadow-free roof area, accounting for water tanks, AC units and roof obstructions. Flat RCC roofs, sloped asbestos/tile roofs and metal sheet roofs are all suitable.

Solar Panels: 25–30 years functional life. Tier-1 panels come with 25-year linear performance warranty (at least 80% output at year 25).

Inverters: String inverters typically last 10–15 years. Microinverters (Enphase) have 25-year warranty.

Mounting Structures: Galvanized/aluminium structures typically last 25+ years.

Batteries (Hybrid): LFP batteries have 4,000–6,000 cycles, typically 10–15 years.

The overall system provides excellent returns throughout its 25-year life, with payback in just 4–6 years.

Solar panels generate electricity even on cloudy days — typically 20–40% of peak production. Kerala's tropical monsoon is accounted for in the 4 units/kW/day annual average. During heavy rain days, KSEB grid supply continues for on-grid systems. For hybrid systems, battery provides backup. Modern bifacial panels also utilize diffused light and ground-reflected light for better performance in low-light conditions. The annual average of 4 units/kW/day is a conservative, real-world figure for Kerala.

PM Surya Ghar Muft Bijli Yojana (PMSG MBY) is a flagship Government of India scheme launched in 2024 to promote rooftop solar for residential consumers. It provides direct financial subsidy:
• 1 kW system → ₹30,000 subsidy
• 2 kW system → ₹60,000 subsidy
• 3 kW and above → ₹78,000 subsidy (maximum — subsidy is capped at 3 kW equivalent)

The subsidy is directly credited to your bank account (or loan account) by the Government of India within approximately 30 days of system commissioning and KSEB approval. There is no need to travel to any government office — we handle the entire registration and subsidy application on your behalf.

To be eligible for PMSG MBY subsidy:
• Must be an Indian resident and owner (or tenant with owner consent) of the property
• Must have an active KSEB electricity connection (LT domestic — LT1 category)
• Must not have previously availed any solar subsidy
• Must register on the national PMSG portal (pmsuryaghar.gov.in) — we assist with this
• Maximum system capacity eligible: 10 kW per household
• Only residential consumers (households) are eligible for this subsidy. Commercial and industrial customers are not eligible for PMSG subsidy.

The entire PMSG subsidy process is online and paperless. Here's how it works:
1. After installation, we submit system details on the national PMSG portal with your KSEB connection details.
2. KSEB inspects the installation and updates the national portal with approval.
3. Government of India processes the subsidy and transfers it directly to your registered bank account (Aadhaar-linked/KSEB-linked) within approximately 30 days.
4. If you have taken a solar loan, the subsidy is credited to your loan account, reducing your outstanding balance.

You do NOT need to visit any government office. Zolar Roof handles all portal registrations and follow-ups as part of our installation service.

Net metering is a KSEB policy that allows solar customers to export surplus electricity to the grid and receive credit for it. A bi-directional (net) meter replaces your old meter and measures both import (from KSEB) and export (to KSEB) separately.

How billing works: Your KSEB bill = Units consumed from grid MINUS units exported to grid. If you export more than you consume, the surplus units carry forward as credit to your next bill.

Important billing change: Without solar, KSEB bills domestic customers every 2 months (bi-monthly). After solar installation, your billing frequency changes to monthly. Use our calculator to compare your 1-month and 2-month bills.

It is possible to achieve near-zero bills with a properly sized solar system, but rarely absolute zero. Here's why:
• KSEB always charges a minimum Fixed Charge (₹50–₹310/month depending on slab) and Meter Rent (₹12/month).
• Electricity consumed at night cannot be offset by real-time solar generation (only by net metering credits).
• In months with heavy monsoon, solar production is lower and you may have a small net import.

Practically, a well-sized system can reduce your monthly bill to just ₹62–₹150 (fixed charge + meter rent), compared to bills of ₹1,000–₹10,000 without solar. This represents savings of 85–97% on your electricity cost.

KSEB LT-1 (Domestic) Tariff — Effective May 2026:

Telescopic Slabs (0–250 units):
• 0–50 units: ₹3.35/unit + ₹50 fixed charge
• 51–100 units: ₹4.25/unit + ₹85 fixed charge
• 101–150 units: ₹5.35/unit + ₹105 fixed charge
• 151–200 units: ₹7.20/unit + ₹140 fixed charge
• 201–250 units: ₹8.50/unit + ₹160 fixed charge

Non-Telescopic Slabs (above 250 units — flat rate on ALL units):
• 251–300 units: ₹6.75/unit + ₹240 fixed charge
• 301–350 units: ₹7.60/unit + ₹250 fixed charge
• 351–400 units: ₹7.95/unit + ₹260 fixed charge
• 401–500 units: ₹8.25/unit + ₹285 fixed charge
• 501+ units: ₹9.20/unit + ₹310 fixed charge

Plus ₹12/month Meter Rent for all consumers.
Use our online calculator for instant bill estimates.

On-Grid Solar System:
• Connected to KSEB grid only (no battery storage)
• Shuts down automatically when KSEB power fails (safety requirement — anti-islanding)
• Lower cost, faster payback
• Best for: Areas with reliable KSEB supply and net metering

Hybrid Solar System (On-Grid + Battery):
• Connected to KSEB grid AND has battery storage
• Continues to supply power even during KSEB outages
• Charges battery during the day from solar; battery powers loads at night or during outages
• Higher upfront cost, but provides energy independence
• Best for: Homes with frequent power cuts, critical loads (medical equipment, home office, EV charging)

Learn more about our hybrid systems →

String Inverter:
• All panels connected in series to one central inverter
• If one panel is shaded, it affects all panels in that string
• Lower cost, simpler system
• Best for: Unobstructed roofs without shading

Micro Inverter (e.g., Enphase IQ8):
• Each panel has its own independent micro inverter
• Each panel works independently — shading one panel doesn't affect others
• Panel-level monitoring available
• Higher cost, but better performance in partial shading conditions
• 25-year warranty from Enphase
• Best for: Roofs with multiple orientations, shading from trees/water tanks, premium installations

Yes, in most cases it is possible to retrofit battery storage to an existing on-grid system. However, the feasibility depends on the type of inverter already installed:

• If you have a Hybrid-ready inverter (like certain Deye or Growatt models with battery ports): Battery can be added directly
• If you have a standard string inverter: A separate AC-coupled battery system (like an Enphase IQ Battery or AC-coupled inverter) needs to be added
• If you have Enphase microinverters: Enphase IQ Battery can be added seamlessly at any time

We recommend planning for future battery addition when selecting your initial system. Our experts can advise on the most cost-effective upgrade path.

For loans up to ₹2 lakh (up to 3 kW systems):
• No income proof required
• No additional collateral — only hypothecation of the solar rooftop system itself
• Minimum CIBIL score: Not required
• Interest rate: ~6% p.a. (RBI Repo Rate + 0.50%)
• 10% co-payment mandatory

For loans above ₹2 lakh (above 3 kW):
• Basic income proof required (salary slip, 2-year Form 16, ITR, etc.)
• CIBIL score 650+ required
• 20% co-payment mandatory
• Interest rate: ~9% p.a.

Use our EMI calculator to plan your loan. For assistance with loan application, contact us.

For government-subsidized PMSG residential installations, the regulatory process requires payment upfront to the installer (Zolar Roof) before KSEB commissioning. This is because subsidy is processed post-installation by the Government of India directly to your account.

However, you can structure your payment using:
1. Bank Solar Loan (recommended) — Pay only 10–20% upfront, bank pays us directly
2. Credit Card EMI — Use high-value credit cards on EMI (contact us for available options)
3. Personal Finance Options — Various NBFCs offer solar EMI plans

For commercial and industrial systems, staged payment terms may be negotiated. Contact our sales team for details.

Step-by-step process for a residential PMSG solar installation:

Step 1: Contact us → Free site survey by our engineers
Step 2: We prepare a detailed quotation with system design and ROI analysis
Step 3: PMSG portal registration (we assist) → KSEB net metering application
Step 4: KSEB application processing & approval (3–7 business days)
Step 5: Bank loan application (if required) → Disbursement (10–14 days)
Step 6: Material procurement → Installation (1–3 days for residential)
Step 7: KSEB inspection → Net meter installation (7–14 days after application)
Step 8: System commissioning → PMSG subsidy application
Step 9: Subsidy credited by GoI within 30 days → System handover + monitoring app setup

Total timeline: Approximately 3–6 weeks from first contact to full operation.

Solar systems are very low maintenance compared to other power generation systems. Here's what's typically required:

Monthly: Panel cleaning — remove dust, bird droppings and debris. A clean panel can produce 5–15% more power than a dirty one.

Quarterly: Check all electrical connections, inverter status, monitoring data.

Annually: Professional inspection — check mounting structure integrity, DC cable insulation, earthing, inverter firmware updates, performance review.

Zolar Roof offers Annual Maintenance Contracts (AMC) for comprehensive year-round service and monitoring. Contact us for AMC pricing.

Typical warranties for systems installed by Zolar Roof:

• Solar Panels: 12-year product warranty + 25-year linear performance warranty (at least 80% output at year 25) from Tier-1 manufacturers
• String Inverter: 5–10 year manufacturer warranty (extendable)
• Enphase Micro Inverter: 25-year manufacturer warranty
• Deye Hybrid Inverter: 5-year manufacturer warranty
• LFP Battery: 10-year / 4,000 cycles warranty
• Mounting Structure: 10-year structural warranty
• Zolar Roof Installation Workmanship: 1-year workmanship warranty

All warranty claims are handled by Zolar Roof directly — you don't need to deal with manufacturers.

Solar systems can be insured against physical damage, natural disasters and lightning. We strongly recommend getting your solar system insured as part of your home insurance policy or separately.

For loan amounts above ₹2 lakh (SBI solar loan): Insurance is mandatory as per bank guidelines. Insurance cost is borne by the customer.

Lightning protection: Our systems include lightning arrestors and proper earthing as per MNRE and KSEB guidelines to protect against direct and indirect lightning damage.

Storm/cyclone: Our mounting structures are designed to withstand wind speeds up to 150+ km/h as per IS standards applicable for Kerala's coastal regions.

Yes, professionally installed solar systems are completely safe for your building. Here's how we ensure roof safety:

• RCC flat roofs: Concrete ballast mounting systems (no drilling required) or properly sealed anchor bolts with waterproofing
• Asbestos/Mangalore tile roofs: Purpose-built tile hooks and L-feet with rubber gaskets — no damage to roofing material
• Metal sheet roofs: Special metal roof clamps and seam-mount systems

Our installations are done by trained technicians following MNRE and IS standards. Structural loading is assessed during site survey. Solar panels actually protect the roof underneath from direct UV and rain impact — many customers report cooler rooms after installation.

Yes! All modern solar systems include real-time monitoring capabilities via smartphone apps:

• Deye/SolarMAN app: Real-time generation, consumption, battery status, grid export/import. Available for iOS and Android.
• Enphase Enlighten app: Panel-level production monitoring, system health alerts, historical data analysis.
• Most String Inverters: Web portal and app monitoring via built-in WiFi or data logger.

You'll be able to see how many units your solar is generating, how much you're saving, battery charge levels (for hybrid), and get alerts for any system issues — all from your smartphone.