Questions and answers
Straight answers on PM Surya Ghar subsidy, net metering, system size, batteries, prices, delivery and warranty. Still unsure? Ask the desk on WhatsApp.
How much solar do I need for my home?
Add up 12 months of units from your bills and divide by your city's yearly yield, about 1,400–1,650 units per kW. For example, 300 units a month (3,600 a year) in Pune needs about 2.4 kW, so most homes install 3 kW. See /learn/solar-for-300-units/.
How much solar do I need for 200 units a month?
About 1.5–1.8 kW in most Indian cities; most families install 2 kW for headroom. A 2 kW system makes roughly 2,800–3,300 units a year. See /learn/solar-for-200-units/.
How much solar do I need for 500 units a month?
About 3.6–4.3 kW depending on your city. Most homes choose 4 or 5 kW. Both get the same central subsidy because it is capped at 3 kW. See /learn/solar-for-500-units/.
How many units does 1 kW of solar produce in India?
Roughly 1,400–1,650 units a year, or about 4–4.5 units a day on average, depending on location, tilt, shade and dust. UP cities sit near the low end; Gujarat and Rajasthan near the high end.
How much roof space does 1 kW need?
About two modules of 540–590 Wp, covering roughly 5–5.5 square metres of panel area. Including walkways and row gaps on a flat roof, plan about 8–10 square metres (85–110 sq ft) of shadow-free area per kW.
Which direction should solar panels face in India?
South is best, tilted roughly 10–25° depending on latitude. East or west faces lose some output but can work; put each direction on its own inverter MPPT. Avoid north-facing slopes.
Does shade really matter?
Yes. Shade on even part of one module can pull down a whole string. Check shadows from tanks, staircase rooms, trees and nearby buildings at 9 am and 3 pm in December, when shadows are longest.
Can I install solar on a tin or sheet roof?
Yes. Modules sit on rails fixed to the sheet crests with sealed screws, and fixings should reach the purlins where the sheet is thin. Rusted sheets should be replaced first.
What is the difference between kW and kWh?
kW is power, the size of the system. kWh (a unit on your bill) is energy, power used over time. A 3 kW system running at full output for one hour makes 3 kWh.
Will solar work on cloudy days?
Yes, but output falls. Under heavy cloud a system may make a small fraction of a sunny day. Net metering banks sunny-day surplus to cover cloudy days. See /learn/solar-in-monsoon/.
How much is the PM Surya Ghar subsidy?
₹30,000 per kW for the first 2 kW and ₹18,000 for the third kW, capped at ₹78,000. Special-category states get ₹33,000 and ₹19,800 per kW, up to ₹85,800. Check the current notification on pmsuryaghar.gov.in.
How do I apply for the PM Surya Ghar subsidy?
Register on pmsuryaghar.gov.in with your consumer number, choose a registered vendor, get DISCOM approval, install a DCR on-grid system, get the net meter fitted and inspected, then submit bank details. Steps: /learn/pm-surya-ghar-subsidy-apply/.
Who is eligible for PM Surya Ghar?
An Indian household that owns the house and roof, has a valid domestic electricity connection, and has not taken a central rooftop solar subsidy before on that connection. The system must use DCR modules, a registered vendor and net metering.
How long does the subsidy take?
After commissioning and bank-detail submission, it is typically credited within about 30 days. From application to credit, many people report one to three months, depending on the DISCOM.
Do any states add to the central subsidy?
Yes, some. UP adds ₹15,000 per kW up to ₹30,000; Rajasthan adds ₹17,000 for eligible 1.1 kW systems; Chhattisgarh and Andhra Pradesh (for SC/ST and BC homes) also add support. Check the current notification.
Is there a subsidy for housing societies?
Yes. Group housing societies and RWAs get ₹18,000 per kW for common facilities, including EV charging, up to 500 kW and 3 kW per house. See /learn/solar-for-housing-societies/.
Can I get a loan for rooftop solar?
Yes. PM Surya Ghar offers collateral-free loans through public sector banks, with interest linked to the repo rate (about repo + 0.5%). Check the current rate with your bank.
Do businesses get the PM Surya Ghar subsidy?
No. It is for residential consumers and housing societies. Businesses can still save heavily because commercial tariffs are high, and may have tax benefits. See /learn/solar-for-shops-and-small-business/.
Is the PM Surya Ghar scheme open after March 2027?
The approved scheme period runs to FY 2026-27. Check for an official extension before planning commissioning after March 2027.
What is net metering?
A bi-directional meter records units you import and export. You pay for the net difference, and surplus is carried forward and settled at a fixed rate at the end of the period. See /learn/net-metering-explained/.
How much does the DISCOM pay for surplus solar units?
Usually ₹2 to ₹3.90 per unit in 2026, depending on the state, and sometimes only as a bill credit. That is why systems should be sized to your yearly use.
Is net metering settled monthly or yearly?
It depends on the state. Maharashtra, UP and MP settle annually; Karnataka, Telangana and Andhra Pradesh settle monthly; Gujarat settles each billing cycle. Check your state's current regulation.
Will my electricity bill become zero?
Rarely fully zero. Fixed charges, meter rent and some taxes stay, and monsoon months produce less. The energy part of the bill usually falls sharply over the year.
Can I install more solar than my sanctioned load?
In most states, rooftop solar is limited to your sanctioned load. Apply for load enhancement along with the solar application if you need a bigger system.
What is a generation meter?
A separate meter that records total solar output. Some states and categories require it (for example where a charge is levied on gross generation); many DISCOMs no longer ask for it on small homes.
Does an on-grid solar system work during a power cut?
No. On-grid inverters switch off when the grid fails, to protect line workers. For backup you need a hybrid inverter with a battery.
Should I choose on-grid, hybrid or off-grid?
On-grid gives the best payback and the subsidy; hybrid adds battery backup at higher cost; off-grid suits places without a reliable grid. See /learn/on-grid-vs-hybrid-vs-off-grid/.
Do I need a battery with solar?
Usually not for savings under net metering, because the grid banks your surplus. A battery is worth it for frequent outages, some time-of-day tariffs, or where rules require storage. See /learn/do-i-need-a-solar-battery/.
LFP or lead-acid battery for solar?
LFP (lithium iron phosphate) lasts more cycles, can be discharged deeper, needs no topping up and is compact. Lead-acid is cheaper upfront. For daily solar cycling, LFP is usually better value over its life.
Can I keep my existing home inverter and battery?
Yes. Add an on-grid solar system for savings and keep your existing UPS for outages. Or replace both with a hybrid when the old batteries are near the end of life.
What does rooftop solar cost per kW in 2026?
About ₹46,000–70,000 per kW installed before subsidy for a complete on-grid system; small systems cost more per kW and DCR modules sit in the upper half. See /learn/solar-cost-per-kw-2026/.
What is the GST on solar panels?
Solar modules and solar power devices moved from 12% to 5% GST from 22 September 2025. Batteries, cables, switchgear and services are generally 18%. Composite contracts often work out near 8.9%. Check with your CA.
What is the payback period of rooftop solar?
With the subsidy, often 3–5 years for homes, and less in high tariff slabs. Without subsidy, 4–7 years is common. See /learn/solar-payback-and-irr/.
Is solar a better investment than a fixed deposit?
On typical assumptions, home solar earns an IRR well above FD rates (an SBI 5–10 year FD paid 6.05% in October 2026). Returns depend on your tariff, usage and system quality, and are not guaranteed like an FD.
Why do solar quotes differ so much?
Module type and brand, inverter, structure height and steel, anchors, earthing, lightning protection, cable sizes and service terms. Compare the same specification line by line. See /learn/choosing-a-solar-installer/.
What is a DCR solar panel?
A module made with Indian-made cells and assembled in India, verified on the NISE DCR portal. DCR is mandatory for the PM Surya Ghar subsidy. See /learn/dcr-vs-non-dcr-solar-panels/.
Can I use non-DCR panels on my home?
For new net-metered systems commissioned from 1 June 2026, modules must use ALMM List-II approved cells, which in practice means Indian cells. Non-DCR modules still suit off-grid systems. Check the current notification.
TOPCon or PERC panels?
TOPCon generally loses less power in heat, degrades more slowly and often carries a 30-year performance warranty, at prices close to PERC. It is the default choice for most new rooftops. See /learn/topcon-vs-perc-vs-bifacial/.
Are bifacial panels worth it on a house?
Only if light reaches the back: an elevated structure over a light-coloured roof, a carport or a pergola. On a low structure over a dark slab the gain is small.
How long do solar panels last?
Good modules carry 25–30 year performance warranties, with output typically guaranteed at around 85–88% at the end. Inverters usually last 10–15 years, so plan one replacement.
How do I choose a good solar installer?
Check registration for your DISCOM, ask for an itemised quote with exact models, ask how the structure is anchored and earthed, and speak to past customers. Checklist: /learn/choosing-a-solar-installer/.
Does Sunlectric install solar systems?
No. Sunlectric is a multi-brand distributor. We supply installers and can connect you with a registered installer in our network who buys genuine, documented material from us. WhatsApp +91 89567 89307.
How often should I clean my solar panels?
Every 2–4 weeks in dry, dusty months, less in the monsoon. Use soft water and a soft brush or mop, early morning or evening. Avoid pressure washers and detergents. See /learn/solar-panel-cleaning-maintenance/.
What maintenance does a solar system need?
Regular cleaning, a glance at the inverter app, and a yearly technician check of earthing, connections, SPDs and structure bolts. PM Surya Ghar systems include five years of vendor maintenance.
Why does my inverter show grid over-voltage?
On tail-end feeders the grid voltage can rise above the inverter's limit at midday. Ask the installer to check AC cable size and ask the DISCOM to check the transformer. Do not raise trip limits beyond what is allowed.
Is rooftop solar safe in lightning storms?
Yes, with proper earthing, a lightning arrester with an adequate down conductor, and surge protection devices on the DC and AC sides. See /learn/rooftop-solar-earthing-lightning/.
Will solar panels leak water into my roof?
Not if anchored correctly. On thin slabs, chemical anchors sealed with PU sealant are safer than expansion bolts. Ask your installer how they will fix and seal the structure.
How much extra solar do I need for an electric car?
Roughly 1–1.5 kW per 1,000 km a month for a typical compact electric car, depending on its consumption and your city. See /learn/ev-charging-with-solar/.
Can apartment owners use solar?
Usually through the society: a common-area system on the roof reduces the common bill for all members. Some states allow group or virtual net metering to credit several meters. See /learn/solar-for-housing-societies/.
Which line on my bill shows what solar can save?
Energy charges, wheeling, fuel adjustment (FAC/FPPAS) and most duty scale with units, so solar reduces them. Fixed charges and meter rent stay. See /learn/read-your-electricity-bill/.
Do free-unit schemes reduce solar savings?
Yes. In states such as Karnataka, Telangana, Tamil Nadu and Rajasthan, eligible homes get some units free, so solar only saves on units you pay for. Size for those units.
What minimum temperature should I use for string Voc?
The site's extreme annual minimum ambient, not the January mean. As a start: about 10°C south of 15°N, 5°C for 15–24°N, 0°C above 24°N, −5°C in hill states. See /learn/string-sizing-indian-temperatures/.
How many 550 Wp modules fit a 600 V string?
With a typical 550 Wp PERC module (Voc about 49.9 V, −0.27%/°C), cold Voc at 5°C is about 52.6 V, so 11 is the maximum. A 585 Wp TOPCon module may drop to 10. Use your datasheet.
When are string fuses needed?
When three or more strings are paralleled on one input. Fuse both poles with gPV fuses rated per IEC 62548 and within the module's maximum series fuse rating.
What DC/AC ratio should I design for?
About 1.1 for residential and 1.2 for commercial is a sensible target; below 0.9 the inverter is underused and above 1.3 clipping grows. See /learn/solar-inverter-selection-dc-ac-ratio/.
Why check MPPT input current?
Modern 182 mm and 210 mm cell modules have Isc of about 14–18 A. Older inverters with 12.5 A inputs clip their current and lose energy. Match module current to the MPPT limits.
Is 16 sq mm aluminium enough for the LA down conductor?
Not by IS/IEC 62305-3, which lists 50 mm² minimum for stranded or round aluminium (70 mm² for tape), copper or galvanised steel. A 25 × 3 mm GI strip (75 mm²) meets the steel minimum. See /learn/rooftop-solar-earthing-lightning/.
How many earth pits for a home system?
Common practice is three, for DC (frames), AC (inverter and ACDB) and the lightning arrester, at least about 3 m apart, with test points. Decide the interconnection scheme per IS/IEC 62305 and your specification.
What SPD voltage rating suits Indian AC feeders?
Use AC SPDs with Uc around 320 V. Tail-end feeders often run at 250–270 V, which ages 275 V devices quickly.
What voltage drop should I allow?
A common target is about 1.5% on the DC side at hot Vmp and about 1.5% on the AC side from inverter to meter, unless the project specification says otherwise. See /learn/solar-cable-sizing-voltage-drop/.
What DC cable should I use?
1.5 kV solar cable to EN 50618, IEC 62930 or IS 17293: 4 sq mm for most residential strings, 6 or 10 sq mm for long runs or paralleled strings. Never use house wire on the DC side.
Mechanical or chemical anchors on RCC roofs?
On typical 100–125 mm house slabs, chemical anchors are safer; M12 expansion anchors can crack thin slabs and lose uplift capacity. Use mechanical anchors only on slabs of about 150 mm or more.
Which wind speed should my structure be designed for?
The basic wind speed from IS 875 (Part 3):2015 for the site, adjusted for design life, terrain and height, topography and cyclone importance. It ranges from 33 m/s to 50 m/s and above. See /learn/solar-structure-wind-load-is-875/.
How much wind uplift acts on one module?
At 39 m/s basic wind speed, design pressure is about 0.9 kN/m². With a net coefficient around 1.2 on a 2.6 m² module, uplift is roughly 2.8 kN, about ten times the module's weight. Real values need a proper design.
What is ALMM List-II?
MNRE's approved list of solar cell makers. From 1 June 2026, net-metering and open-access projects must use ALMM List-I modules made with List-II cells, with limited exceptions. See /learn/almm-explained-for-installers/.
Are there exemptions from ALMM List-II?
Net-metered projects commissioned before 1 June 2026 are exempt, some government tenders by bid date, case-by-case extensions, and PM Surya Ghar 'Give It Up' applicants until 31 March 2027. Check the current notification.
How should I bill GST on a rooftop job?
Either itemise (modules and solar inverters at 5%, most BOS and services at 18%) or bill a composite solar power generating system contract valued 70:30, about 8.9% effective. Take your CA's advice and invoice consistently.
What tests should I do at commissioning?
Polarity, string Voc and current, insulation resistance, earth continuity and earth resistance, AC protection checks, inverter settings and an anti-islanding check, all recorded. See /learn/solar-commissioning-checklist/.
Does the CFA count DC or AC capacity?
MNRE counts the lower of module (DC) and inverter (AC) capacity. A 3.3 kWp array on a 3 kW inverter is treated as 3 kW for subsidy.
Can I put a single-phase inverter on a three-phase connection?
Often, up to a DISCOM limit, commonly about 5 kW (MSEDCL practice). Above that use three-phase. Above 10 kW the connection must be three-phase under CEA rules.
What is the grid support charge in Maharashtra?
MERC levies it on gross generation for rooftop systems above 10 kW: ₹1.96 per unit for LT and ₹1.42 for HT in FY27. Model it for societies and commercial jobs. Check the current order.
Which Karnataka export rate applies to subsidised systems?
KERC's August 2026 order gives ₹3.89 per unit without capital subsidy, and ₹1.96, ₹2.14 or ₹2.58 for systems up to 2 kW, 2–3 kW and above 3 kW that take the PM Surya Ghar subsidy.
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