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In built-up Central Delhi, the top of the building is often the only part of a house that gets clean, unshaded sunshine — which is exactly why this Karol Bagh home’s solar system sits above the water tanks and the staircase headroom. On 19 October 2026, Thermosun completed a 4kW rooftop solar installation at this Sant Nagar address, and the thing worth explaining isn’t the panels. It’s the frame holding them up. A solar system on a top floor catches the most sun, and it also catches the most wind.
Project Overview & Highlights
This Karol Bagh installation sits on a galvanized steel frame at the highest level of the building, above rooftop water tanks. Here’s exactly what was delivered:
Top-Floor Terrace in Karol Bagh or Central Delhi?
The sunniest roof is also the most exposed one. A free site survey from a solar installation company Delhi homeowners trust looks at structure strength first, not just panel count.
📞 Call Now 📄 Free Site SurveyTop-Floor Roof, Highest Sun — and Highest Wind
Delhi’s pre-monsoon months bring dust storms that can arrive with very little warning, with gusts well above 70 km/h. On the ground you feel it as a rush of dust; on a four-storey roof, a tilted panel acts a bit like a sail. The higher and more open the roof, the stronger the wind loading on the structure.
🌪️ What Actually Keeps a Rooftop Array in Place
- Bracing: diagonal braces between the steel columns stop the frame from racking sideways in a gust — you can see them running between the legs in the photo.
- Anchoring: the frame has to be firmly fixed to the roof structure. Panels tilted into the wind create uplift, so a frame that’s merely resting on the slab isn’t enough.
- Galvanized steel: a zinc-coated frame resists corrosion through Delhi’s humid monsoon and dusty summers, so it stays strong for the 25 years the panels are warrantied.
- Sensible height: the frame is only as tall as the roof’s obstructions require — here, clearing the water tanks. Every extra metre of height adds wind exposure.
This is why a rooftop solar installation Delhi homeowners can rely on starts with the structure, not the panel brochure. The relevant Indian standard for wind loads on structures is IS 875 (Part 3), and it’s fair to ask any installer how their frame is designed against it. After a major storm it’s also sensible to have the frame glanced over — bolts tight, braces intact, nothing shifted.
KSolare 5G Pro Inverter — DC/AC Setup Explained
This 4kW system runs on a KSolare 5G Pro single-phase grid-tied inverter, installed between a DC panel box on the panel side and an AC panel box with MCB and surge protection on the grid side, all along a neat cable tray with conduit-protected wiring.
One small tip for anyone comparing quotes for a solar system: every inverter has a maximum input rating, and the caution label on the unit lists the panel configuration it’s designed for. Adding more panels than the inverter is rated for can affect performance and may void the warranty — so the panel count and the inverter should always be matched deliberately, not just maximised to make a bigger-sounding kilowatt figure.
Net Metering With BYPL Explained
Karol Bagh falls under BSES Yamuna Power Limited (BYPL), which serves Central and East Delhi — a different DISCOM from the BRPL that covers most of South and West 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.
Real Savings — What This Home Now Earns
With the array generating power and net metering active through BYPL, here’s the estimated monthly financial picture for this 4kW system. Actual figures depend on consumption, season and panel cleanliness:
| Benefit | 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 & Exposure Check Roof level, water tank positions, shading from neighbouring buildings and wind exposure assessed.
- 2Braced Frame Design Galvanized steel structure designed with diagonal bracing and anchoring suited to a top-floor roof.
- 3Procurement of ALMM-Approved Components Panels and KSolare inverter sourced from the MNRE-approved list for subsidy eligibility.
- 4Panel Installation Full 4kW array mounted and wired across the braced frame.
- 5Inverter & DC/AC Panel Box Setup KSolare 5G Pro installed with protection devices, 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.
Karol Bagh, Patel Nagar & Across Central Delhi — We Cover Your Area
As a solar EPC company in Delhi handling design, installation, net metering and subsidy paperwork, Thermosun serves Karol Bagh and the wider BYPL belt of Central and East Delhi directly.
💬 WhatsApp Now 📄 Free Site SurveyWhy Choose Thermosun
Anyone can bolt panels onto a roof on a calm afternoon. The test comes in the first May storm, which is why we spend as much time on bracing, anchoring and frame height as on the electrical side. That attention to structure, across more than 1,000 installations, is a big part of why homeowners in dense Central Delhi colonies call Thermosun the best solar company in Delhi for solar for home projects on exposed top-floor roofs, where a cheap frame becomes an expensive problem.