Questions people actually ask us
Subsidy, KSEB net metering, the monsoon, coconut palms, salt air and what happens when the power cuts. If your question is not here, ask us directly.
Subsidy and cost
- How much subsidy do I actually get?
- Under PM Surya Ghar: Muft Bijli Yojana a domestic consumer gets ₹30,000 per kW for the first 2 kW and ₹18,000 for the third. That works out at ₹60,000 on a 2 kW system and ₹78,000 on anything 3 kW or larger. ₹78,000 is a hard ceiling, so a 10 kW system draws the same subsidy as a 3 kW one. Housing societies get ₹18,000 per kW on common facilities up to 500 kW. Commercial and industrial connections get no capital subsidy, but they can claim 40% accelerated depreciation in the first year.
- When does the money reach me, and who claims it?
- We claim it. Once KSEB issues your commissioning certificate we upload it with your bank details on the national portal, and the subsidy is transferred to your account, usually within 30 days. You pay the full amount up front and get the subsidy back afterwards. It is not deducted from our invoice. If someone offers to “adjust” the subsidy inside their quote, they are asking you to trust them with your claim.
- What does a system cost in Kerala?
- Turnkey rates run around ₹60,000 per kW for a small domestic system and fall towards ₹43,000 per kW at commercial scale. A typical 3 kW home system is about ₹1.8 lakh before subsidy and roughly ₹1.02 lakh after. That price covers modules, inverter, mounting structure, DC and AC cabling, earthing, surge protection, installation, KSEB liaison and commissioning. Coastal sites sometimes carry a small premium for marine-grade structure, and we put that in the quote rather than mentioning it afterwards.
- Why is your system bigger than the one I was quoted elsewhere?
- Because we size about 20% above your consumption. A system matched exactly to your units on paper falls short of them on a roof: dust between cleans, a passing shadow, heat derating in April and the panels' own ageing all take a bite. The headroom is what makes full offset hold up in year five as well as year one. It costs a little more up front and a little of the surplus goes back to KSEB at the buyout rate rather than saving you retail, and we think that is the right trade. If you would rather have the smaller system, say so and we will quote it.
- Can I finance it?
- Yes. Rooftop solar for homes qualifies for collateral-free loans under RBI's priority sector lending norms, at rates around 7% and tenures up to 10 years. Kerala Bank, the state co-operative banks and most nationalised banks lend against it, several of them through the national portal. The saving on a KSEB bill usually exceeds the EMI, so most customers are cash-flow positive from the first month.
KSEB bills and net metering
- Why does my bill come every two months?
- KSEB reads domestic meters bi-monthly, so a domestic bill covers about 60 days and the slabs are applied to the monthly average. Our calculator asks for the amount and the period together for that reason. A ₹3,000 bill means very different things over one month and two, and getting it wrong would size your system half right.
- What is net metering, in plain terms?
- Your meter is replaced with one that counts in both directions. During the day your panels supply the house and push the surplus onto the grid, raising the export count. At night you draw from the grid and the import count rises. KSEB bills you on the difference. The grid ends up storing your daytime surplus for you at no cost.
- Why does the saving look bigger than my units times my tariff?
- Because KSEB's domestic tariff is telescopic below 250 units a month. The first 50 units cost ₹3.35 each and the band from 201 to 250 costs ₹8.50. Above 250 units the tariff turns non-telescopic and one rate applies to everything you used. Solar removes your last units first, which are the expensive ones, and then walks you back down through the slabs. So the saving is the difference between two bills, not your consumption multiplied by an average rate. Our calculator works it out that way.
- Will my bill actually go to zero?
- The energy portion can get very close. The fixed charge, meter rent and electricity duty stay on the bill however much you generate, usually a few hundred rupees per bi-monthly cycle. Our calculator keeps those in deliberately, which is why it shows a small residual instead of a headline zero. A three-phase connection carries a noticeably higher fixed charge than a single-phase one.
- What happens to surplus I never use?
- Unused export is banked in units and carries forward within the settlement period, which KSERC sets at a financial year. Whatever is left at the end gets bought out by KSEB at around ₹3.15 a unit, well under retail. We size a system to your consumption for that reason. A banked unit is worth about a third of a unit you use yourself.
- Is there a limit on system size?
- KSERC's regulations cap rooftop systems at your sanctioned connected load, and net metering has its own cap. Domestic consumers are generally kept within 10 kW, and larger systems move to other settlement arrangements. Your section office also has a view on how much the local transformer can absorb. We check both during the survey and size within them.
Monsoon, palms and Kerala roofs
- Does solar work through the Kerala monsoon?
- It works, but output falls sharply. Expect 40% to 60% down in June and July, and remember Kerala gets two monsoons: the south-west from June, and the north-east through October and November. Panels still generate on diffuse light. The annual figures we quote already average both monsoons in, and net metering carries your February surplus forward to cover the July shortfall. Be wary of anyone who quotes you a flat monthly generation figure for a Kerala roof.
- How much does a kilowatt generate here?
- Between about 1,355 and 1,470 units a year depending on your district, so roughly 3.7 to 4 units a day. Palakkad is the best in the state because it sits in the rain shadow of the gap. The high ranges of Idukki and Wayanad are the lowest and lose mornings to hill cloud. The coastal belt sits in between. It is a narrower spread than most of India, since the whole state shares one coastline and the same two monsoons.
- What about coconut palms?
- Palms are the most common problem on a Kerala roof, and the reason our survey looks at shading across the year instead of on the day we visit. A palm that clears the array in December can cut across it at ten in the morning in June. Where shade cannot be avoided we design around it, splitting strings across MPPTs or fitting optimisers, so one frond does not drag down a whole string.
- My roof is Mangalore tile, not concrete. Is that a problem?
- No, it is normal here. Tiled sloping roofs take a different mounting system: brackets bolt to the rafters and carry the load through the structure, and the tiles are reseated around them. The rafters need checking, which the survey does. A sloping roof facing anywhere between south-east and south-west is often better than a flat slab, because the pitch sheds rain and dust on its own.
- Do panels need cleaning in Kerala?
- Less than in most of India, since the rain does much of the work. Through the dry months, and anywhere near a laterite road or a building site, expect to rinse them every three or four weeks. What Kerala does demand is inspection. Humidity, salt and biological growth attack connectors and earthing far faster than dust ever does. Our first five years of maintenance visits are included.
- Kerala gets a lot of lightning. Is that a risk?
- It is, and it is why we do not treat surge protection as an optional line item. Every system we install gets Type 2 SPDs on both the DC and AC sides and a tested earth, and we specify more where the site warrants it. Most of the inverter failures we get called out to on other people's installations trace back to a surge that had nowhere to go.
Installation and living with it
- How long does the whole thing take?
- About six weeks from first call to first unit, of which three days are work on your roof. The rest is KSEB technical feasibility and the Electrical Inspectorate sign-off, which run on their timetable. We file everything in the first week so nothing is sitting with us.
- Will it damage my roof or leak?
- No. On a concrete roof the structure is ballasted or anchored with sealed chemical fixings. On tile we clamp to the rafters and reseat the tiles. Everything is galvanised or aluminium and specified for the wind and salt exposure at your site. The array also shades the slab beneath it, which measurably cools the room below.
- Does solar work when the power cuts?
- A plain grid-tied system shuts down during an outage. It has to, so that KSEB linesmen working on the fault are not fed power from your roof. For backup you need a hybrid inverter with a battery, which islands your home and keeps chosen circuits live. You can fit a hybrid inverter now and add batteries later, and that is usually the cheaper order to do it in.
- I live in an apartment. Can I do this?
- Not on your own, since the terrace is common property. The association can, and the economics are good: ₹18,000 per kW of subsidy against common-area load, which often zeroes the bill for lifts, pumps, corridor lighting and the STP. We are happy to present to the general body if that helps get it through.
- What if I sell the house?
- The system transfers with the property and the warranties go with it. The KSEB connection and the net-metering agreement are re-registered in the new owner's name. Buyers generally treat a commissioned rooftop system as a value-add, since it comes with a documented record of what it saves every cycle.
Warranties and support
- What is warranted, and for how long?
- Panels carry a 25-year linear performance warranty, meaning at least 80% of rated output in year 25, plus 10 to 12 years on the product itself. Inverters are 5 to 10 years and extendable. Mounting structure is 10 years against corrosion, which is the clause to read closely if you are on the coast. Our workmanship is warranted for 5 years, and the first 5 years of maintenance visits are in the price.
- What if a panel fails in year twelve?
- It gets replaced under the manufacturer's warranty. We only specify makers with an Indian service presence and a track record long enough to make that promise credible. It is the main reason we will not quote the cheapest module on the market, and we will tell you when someone else has.
- How do I know it is working?
- Every system ships with monitoring. You see generation live and by day, month and year on your phone. We watch the same data, so if a string drops out we usually know before you do and can call you instead of waiting for a complaint. That counts for most in the monsoon, when a fault is easy to mistake for weather.
- Do you cover my district?
- All fourteen, with our own crews. Response times are quickest around Ernakulam, Thrissur and Thiruvananthapuram, where we are based. The high ranges and Kasaragod take a little longer for an unscheduled call-out. Ring us with your pin code if you are unsure and we will tell you where you stand.
Still deciding?
Run your bill through the calculator for a full estimate, or leave your number and an engineer will talk you through it.