📋 Table of Contents
- Project Overview & Highlights
- How Long Does a Solar System Take to Pay for Itself? A Worked Example
- KSolare 5G Pro Inverter — DC/AC Setup Explained
- Net Metering With BRPL Explained
- Real Savings — What This Home Now Earns
- What Thermosun Handled — Start to Finish
- Why Choose Thermosun
- Frequently Asked Questions
Almost every homeowner who calls about solar asks the same thing before anything else: “How many years until it pays for itself?” It’s the right question, and it’s one that vague brochures dodge. On 27 October 2026, Thermosun completed a 3kW rooftop solar installation in Block F, Mansarover Garden, and rather than quote a single flattering number, this case study walks through the payback sums step by step — with the awkward parts included — so you can run them for your own home.
Project Overview & Highlights
This Mansarover Garden installation sits on a West Delhi rooftop with sheet-roof sections alongside the main terrace. Here’s exactly what was delivered:
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📞 Call Now 📄 Free Site SurveyHow Long Does a Solar System Take to Pay for Itself? A Worked Example
🧮 The Simple Formula
Payback (years) = Net cost after subsidy ÷ Annual benefit, where annual benefit is the electricity bill you save plus any Delhi GBI income. That’s all it is — the skill is in using honest inputs.
Step 1 — the cost. A fully installed 3kW rooftop solar system in Delhi typically costs in the region of ₹1.7–2.0 lakh, depending on panel brand, inverter, mounting structure and site conditions. Treat that as indicative; your own quote is what counts.
Step 2 — the subsidy. Under the currently documented structure, a 3kW residential system receives the ₹78,000 PM Surya Ghar central subsidy plus up to ₹30,000 in Delhi state capital subsidy — ₹1.08 lakh in total. That brings the net cost to roughly ₹62,000–₹92,000.
Step 3 — the benefit. This is where homes differ most, because a solar system can only save what your bill actually contains. Here are two illustrative households:
| Household | Estimated Annual Benefit | Net Cost After Subsidy | Approx. Payback |
|---|---|---|---|
| Higher use — bill around ₹4,000+ a month before solar | ₹38,400 – ₹52,800 | ₹62,000 – ₹92,000 | Roughly 1.5 – 2.5 years |
| Modest use — bill around ₹1,500–2,000 a month before solar | ₹24,000 – ₹31,000 | ₹62,000 – ₹92,000 | Roughly 2 – 4 years |
Illustrations, not guarantees. Actual figures depend on your tariff slab, consumption pattern, seasons and panel cleanliness.
⚠️ The Parts Brochures Skip
- Cash flow: you normally pay the full system cost up front; the subsidy is credited to your bank account after commissioning, not at the time of payment.
- GBI doesn’t last forever: the Delhi Generation-Based Incentive is paid for a limited period (5 years), so long-run savings after that come from the bill reduction alone.
- Inverter replacement: panels are warranted for 25 years, but inverters typically carry a shorter warranty and may need replacing once during the system’s life. Factor that into your lifetime cost.
- Upkeep: a simple periodic wipe-down keeps output close to what the system was sized for.
- Low bills mean slower payback: if your electricity bill is already small, there’s simply less for solar to save. That doesn’t make it a bad idea, but it changes the sums.
Even with all of that included, the payback on a 3kW solar system in Delhi is typically a matter of a few years, followed by two decades of nearly free power — which is why the numbers are worth running before dismissing the idea.
KSolare 5G Pro Inverter — DC/AC Setup Explained
This system runs on a KSolare 5G Pro grid-tied string inverter, mounted on a wall between a DC panel box on the panel side (with isolation and surge protection) and a transparent-covered AC panel box on the grid side. A configuration chart is printed on the inverter’s front label, matching the number of panels to the inverter’s rating — a reminder that panel count and inverter are chosen together, not separately.
Net Metering With BRPL Explained
Mansarover Garden falls under BSES Rajdhani Power Limited (BRPL), the DISCOM covering most of West and South Delhi. After commissioning, Thermosun filed the net metering application with BRPL, 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 BRPL nets the two off at each billing cycle — the mechanism that turns generation into the bill savings in the payback sums above.
Real Savings — What This Home Now Earns
With the system generating power and net metering active through BRPL, here’s the estimated monthly financial picture for this 3kW system, assuming a household with a reasonably healthy bill:
| Benefit | Monthly Value | Annual Value |
|---|---|---|
| Bill Reduction via Net Metering | ₹2,200 – ₹3,200 | ₹26,400 – ₹38,400 |
| Delhi GBI (₹3/unit generated, up to 3kW slab) | ₹1,000 – ₹1,200 | ₹12,000 – ₹14,400 |
| Total Monthly Financial Benefit | ₹3,200 – ₹4,400 | ₹38,400 – ₹52,800 |
📊 Solar Subsidy for This 3kW System
Under the currently documented structure, a 3kW residential system receives the ₹78,000 PM Surya Ghar central subsidy plus up to ₹30,000 in Delhi state capital subsidy (₹10,000/kW) — a combined ₹1.08 lakh, with the Delhi GBI paying ongoing per-unit income on top. Delhi has also announced a revised scheme for eligible low-consumption households, but it isn’t live on the official portal yet. If you’re waiting to see how that could change your payback, see our Delhi Solar Subsidy 2026 guide for what’s confirmed and what isn’t.
What Thermosun Handled — Start to Finish
- 1Site Survey & Bill Review Roof layout, shading and the household’s electricity bill assessed to confirm 3kW was the right size.
- 2Structure Design Galvanized steel mounting designed around the terrace and adjoining sheet-roof sections.
- 3Procurement of ALMM-Approved Components Panels and KSolare inverter sourced from the MNRE-approved list for subsidy eligibility.
- 4Panel Installation Array mounted and wired on the steel structure.
- 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.
- 7BRPL 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.
Mansarover Garden, Ramesh Nagar & Across West Delhi — We Cover Your Area
As a solar EPC company in Delhi handling design, installation, net metering and subsidy paperwork, Thermosun serves Mansarover Garden, Rajouri Garden, Moti Nagar and the wider West Delhi belt directly.
💬 WhatsApp Now 📄 Free Site SurveyWhy Choose Thermosun
We’d rather you walk away with an honest payback figure than a hopeful one. That means telling a low-bill household that their payback will be longer, flagging the inverter replacement most quotes leave out, and explaining that the subsidy arrives after you’ve paid. It’s how we approach every rooftop solar installation Delhi families ask us about, and across more than 1,000 installations it’s a large part of why homeowners call Thermosun the best solar company in Delhi when they want solar for home projects explained plainly before they commit.