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Look at the sky in this photo. It was taken on an overcast, hazy Friday morning in late October, right as Delhi’s smog season begins — not exactly the picture of a sunny solar showcase. And that’s the point. On 30 October 2026, Thermosun completed a 4kW rooftop solar installation at A66, Block D, Mayur Vihar Phase III, and the question we hear every year at exactly this time is: “Will solar even work with all this smog and cloud?” Here’s the honest answer, with the numbers that actually matter for your bill.
Project Overview & Highlights
This Mayur Vihar installation sits on a braced galvanized steel table raised above a crowd of rooftop water tanks, with open sky above and around it. Here’s exactly what was delivered:
Worried Smog Will Ruin Your Solar Returns?
It’s the most common hesitation we hear. A free site survey from a solar installation company Delhi families trust gives you month-by-month generation estimates, smog season included.
📞 Call Now 📄 Free Site SurveyCloudy, Hazy, Smoggy — What Delhi’s Autumn Does to Solar Output
☁️ Short Answer
Yes, solar panels still work on cloudy, hazy and smoggy days — they run on daylight, not just direct sunshine. But output drops with the amount of light reaching the panels, so a grey smog day produces noticeably less than a clear one.
| Condition | Typical Effect on Output | What It Means for You |
|---|---|---|
| Clear sunny day | Best output of the year’s conditions (still a little below rated capacity because of heat and system losses) | Your strongest generation days |
| Thin cloud or light haze | A modest dip | Barely noticeable on a monthly bill |
| Dense smog or heavy overcast | A large dip — often down to a fraction of a clear day | A few bad days don’t change annual output much |
| Rain | Lower output while it lasts | Rain also washes dust off the panels afterwards |
| Dust storm | Short-term dip, then a dust layer | A quick wipe-down restores output |
These are general patterns rather than fixed percentages — the exact dip depends on how thick the haze or cloud is. What matters more for your bill is the bigger picture. November to January are Delhi’s lowest-generation months: days are shorter, the sun sits lower and smog is at its worst. A solar system is sized on annual consumption and output, not on the worst week of December. And because of net metering, units your system exports in strong months are credited and carried forward under your DISCOM’s rules, which helps absorb the winter dip.
✅ A Simple Smog-Season Routine
- Don’t judge by a single grey day. Compare monthly figures with the same month a year earlier, not with a sunny summer month.
- Wipe the panels after a smog or dust episode. Fine particles settle as a film, and cleaning restores output.
- Ask for month-by-month estimates from your installer, so you know in advance that winter will be lower and summer higher.
- Keep the equipment area clear and the extinguisher and isolators accessible, as at this property.
In short, smog is a reason to expect a seasonal dip, not a reason to rule out a solar system. The panels on this Mayur Vihar roof were commissioned under exactly this grey sky and will generate through Delhi’s autumn and winter at whatever output the light allows, then pick up strongly into spring.
Sungrow Inverter — DC/AC Setup Explained
This 4kW system runs on a Sungrow grid-tied string inverter, mounted between a DC panel box on the panel side and an AC panel box on the grid side, all on a clear cable tray with conduit-protected wiring. A compact fire extinguisher is fixed on the wall right beside the equipment.
Net Metering With BYPL Explained
Mayur Vihar falls under BSES Yamuna Power Limited (BYPL), which serves East and Central Delhi. After commissioning, Thermosun filed the net metering application with BYPL, coordinated the inspection, and had the bi-directional meter installed. That meter records the units you draw from the grid and the surplus your system exports separately, and BYPL nets the two off at each billing cycle — which is exactly why a sunny month’s surplus can cushion a smoggy month’s shortfall.
Real Savings — What This Home Now Earns
These figures are annual averages spread across the year — expect winter months to come in lower and summer months higher. With the array generating and net metering active through BYPL, the estimated monthly financial picture for this 4kW system is below. Actual results depend on consumption, season and panel cleanliness:
| Benefit | Average Monthly Value | Annual Value |
|---|---|---|
| Bill Reduction via Net Metering | ₹2,800 – ₹4,000 | ₹33,600 – ₹48,000 |
| Delhi GBI (₹2/unit generated, 3–10kW slab) | ₹900 – ₹1,050 | ₹10,800 – ₹12,600 |
| Total Monthly Financial Benefit | ₹3,700 – ₹5,050 | ₹44,400 – ₹60,600 |
📊 Solar Subsidy for This 4kW System
Under the currently documented structure, a residential system of 3kW or above receives the ₹78,000 PM Surya Ghar central subsidy plus up to ₹78,000 in Delhi state capital subsidy (₹10,000/kW, capped at 3kW) — a combined ₹1.56 lakh. A 4kW system doesn’t raise either cap; the extra return comes from higher generation, plus the Delhi GBI on top. Delhi has also announced a revised scheme for eligible low-consumption households, but it isn’t live on the official portal yet — see our Delhi Solar Subsidy 2026 guide for what’s confirmed and what isn’t.
What Thermosun Handled — Start to Finish
- 1Site Survey & Generation Estimate Roof layout, water tank positions, shading and month-by-month expected output assessed.
- 2Raised Frame Design Galvanized steel table with diagonal bracing designed to clear the tanks.
- 3Procurement of ALMM-Approved Components Panels and Sungrow inverter sourced from the MNRE-approved list for subsidy eligibility.
- 4Panel Installation Full 4kW array mounted and wired across the raised frame.
- 5Inverter & DC/AC Panel Box Setup Sungrow inverter installed with protection devices and extinguisher, fully conduit-protected.
- 6Safety Compliance Earthing and protective wiring documented to IS standard.
- 7BYPL Inspection & Net Meter Net metering application filed, inspection coordinated, bi-directional meter installed.
- 8PM Surya Ghar & Delhi GBI Filed Complete subsidy and GBI registration submitted, bank details confirmed for DBT processing.
Mayur Vihar, Preet Vihar & Across East Delhi — We Cover Your Area
As a solar EPC company in Delhi handling design, installation, net metering and subsidy paperwork, Thermosun serves Mayur Vihar, Patparganj, Anand Vihar and the wider BYPL belt directly.
💬 WhatsApp Now 📄 Free Site SurveyWhy Choose Thermosun
We’d rather tell you in October that winter will be lower than let you find out in December. Setting honest expectations — including the smog-season dip — is how we approach every rooftop solar installation Delhi homeowners ask us about, and with over 1,000 installations behind us, that straight talk is a big reason customers call Thermosun the best solar company in Delhi for solar for home projects where the full-year picture matters more than a best-case brochure figure.