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Look at this South Patel Nagar rooftop from below and you can see something you normally can’t on a solar panel: the pattern of solar cells on the underside. That’s because these are bifacial, glass-glass panels — modules that can generate electricity from both faces. On 27 October 2026, Thermosun completed this 4kW rooftop solar installation, and it’s a good chance to answer a question we hear more and more: are bifacial panels worth it, or is it just a nicer-sounding spec on the quote?
Project Overview & Highlights
This South Patel Nagar installation uses two raised steel tables — a long one spanning the main terrace and a second over the staircase headroom — with open space beneath both. Here’s exactly what was delivered:
Being Pitched Bifacial Panels? Get the Real Numbers First
A good solar installation company Delhi homeowners trust will tell you when bifacial is worth the premium — and when it isn’t. A free site survey checks your actual roof.
📞 Call Now 📄 Free Site SurveyBifacial Panels — What They Are and Whether They Actually Pay Off
☀️ Short Answer
A bifacial panel has solar cells that work on both sides. The front face does the main job; the rear face picks up light reflected from the surface below and from the surroundings, adding some extra generation. How much extra depends heavily on the roof and the mounting — it’s real, but it isn’t guaranteed or constant.
Glass-glass construction means the rear is protected by a second sheet of glass rather than an opaque backsheet. That’s what lets light in from behind, and glass-glass modules are generally valued for durability against moisture and micro-cracks over a long life, though specifications and warranties vary by manufacturer.
The extra output from the rear side — often called rear-side gain — isn’t a fixed number. It depends on a handful of site conditions:
| Factor | Effect on Rear-Side Gain |
|---|---|
| Surface colour below the panels | Light, reflective surfaces (white tiles, light-coloured cool-roof paint) reflect more light up to the rear face; dark or cluttered surfaces reflect much less. |
| Height above the roof | The higher the panels are mounted, the more reflected light can reach the underside. Panels laid almost flat on a roof gain very little. |
| Open space beneath | An open, raised table lets light circulate underneath; boxed-in or obstructed frames limit it. |
| Row spacing and tilt | Spacing and angle affect how much diffuse and reflected light reaches the back, and how much the panels shade each other. |
That’s why bifacial suits a roof like this one. The panels sit on raised tables with open space beneath, rather than being bolted close to the slab, so there’s room for reflected light to reach the rear face. On a low, dark or heavily cluttered roof the same panels would add much less. In practice, rear-side gain on rooftops is usually modest — a few percent in poor conditions and noticeably more with a light-coloured surface and good height — so it’s best treated as a useful bonus, not a headline promise.
Two honest caveats. First, bifacial modules usually carry a price premium over standard ones, so the extra generation has to earn that back; on a suitable roof it often does, on an unsuitable one it may not. Second, for the PM Surya Ghar subsidy the panels must meet the scheme’s domestic-content requirements and be ALMM-listed — your installer should confirm this for the specific bifacial model, not assume it.
KSolare Inverter — DC/AC Setup Explained
This 4kW system runs on a KSolare grid-tied single-phase string inverter, mounted 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. The caution label on the inverter specifies the panel configuration it’s rated for — which is why panel count and inverter are always matched deliberately.
Net Metering With BYPL Explained
South Patel Nagar falls under BSES Yamuna Power Limited (BYPL), which serves Central and East Delhi through divisions including Patel Nagar — 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. These figures are based on standard output; any additional rear-side gain from the bifacial panels would come on top and isn’t counted. Actual results 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 & Panel Selection Roof layout, shading, surface below the frames and the case for bifacial panels discussed before the system was specified.
- 2Raised Table Design Galvanized steel tables designed with open space beneath for airflow and rear-side light.
- 3Procurement of ALMM-Approved Components Bifacial panels and KSolare inverter sourced from the MNRE-approved list for subsidy eligibility.
- 4Panel Installation Full 4kW array mounted and wired across both tables.
- 5Inverter & DC/AC Panel Box Setup KSolare inverter 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.
Patel Nagar, Karol Bagh & Across Central Delhi — We Cover Your Area
As a solar EPC company in Delhi handling design, installation, net metering and subsidy paperwork, Thermosun serves South Patel Nagar, Rajendra Place and the wider BYPL belt directly.
💬 WhatsApp Now 📄 Free Site SurveyWhy Choose Thermosun
Bifacial is a good example of why we don’t sell on spec sheets. We’ll recommend it where the roof and mounting let it perform, tell you plainly where the extra cost won’t be recovered, and check the subsidy eligibility of the exact model before you pay for it. Across more than 1,000 installations, that practical, roof-by-roof approach is a large part of why homeowners call Thermosun the best solar company in Delhi for solar for home projects where the choices on the quote actually matter. Every rooftop solar installation Delhi families trust us with starts with that honesty.