Buy the kilowatts you need. Not the ones being sold.
System size is the most consequential number in your solar project — it sets the cost, the subsidy, the payback and twenty-five years of generation. It deserves better than a salesperson's default. We derive it from your bills, your roof and your city's sun.
Every disappointing solar system we’ve audited failed at the same stage: before purchase. A system sized to the vendor’s inventory rather than the buyer’s consumption. An array laid where the water tank shades it every afternoon. A design that ignored the sanctioned load and stalled at the DISCOM. None of these are installation defects — they are design decisions, made carelessly, that no amount of good workmanship later can undo.
Our survey-and-design service exists to make those decisions carefully, and independently of anyone selling hardware. The load analysis starts from twelve months of your electricity bills — seasonal peaks included — and your sanctioned load. The site assessment measures what your roof actually offers: usable area after obstructions, orientation and tilt options, shading across the day and the seasons, structural and waterproofing realities, and the cable run to your meter. The output is a design brief: recommended capacity with its reasoning, expected monthly generation by season, layout constraints, and the specification installers should quote against.
That last part is the quiet superpower. When three installers quote against one independent specification, their bids become comparable and their assumptions visible. When they each quote their own design, you are comparing stories. The survey pays for itself in negotiation before a single panel is bought.
The design brief, in six parts.
- Load analysis from your bills
- Twelve months of consumption decomposed — seasonal pattern, daytime share, sanctioned load — into the number the system size must answer to.
- Roof & shading assessment
- Usable area after tanks, parapets and structures; orientation and tilt; and shadow paths across the day and the year — the difference between rated and real generation.
- Structural & waterproofing check
- Load-bearing sanity for the mounting system, wind-loading considerations for elevated structures, and how to mount without voiding a waterproofing warranty. Escalated to a structural engineer when genuinely warranted.
- Right-sized recommendation
- Recommended capacity with the reasoning shown — consumption coverage, subsidy slab, roof constraint — plus the honest alternative sizes and what each trades away.
- Generation & savings model
- Month-by-month expected generation for your city's irradiance profile, mapped to your tariff — a conservative model you can hold every vendor promise against.
- Tender-ready specification
- The technical spec — capacity, module and inverter class, mounting, protections, metering — that turns three vendor quotes into one legible comparison.
When the survey earns its keep.
Before collecting quotes
The ideal sequence: survey first, then quotes against the spec. You negotiate from knowledge, and oversizing never gets a foothold.
When quotes disagree wildly
One vendor says 3 kW, another says 5 kW, for the same house. Both can't be right. An independent survey is the tiebreak — and usually explains the difference in one page.
Complex roofs & societies
Multiple levels, heavy shading, old structures, society terraces with competing uses — the situations where a desktop estimate fails and measurement matters.
Where our role stops.
- We don’t sell hardware. The design brief names component classes and standards, never a brand we have a deal with — because we don’t have deals.
- We don’t inflate to impress. If your consumption says 2 kW, the recommendation says 2 kW — even though bigger systems make better headlines and bigger commissions elsewhere.
- We don’t replace the structural engineer. Where a roof genuinely needs certified sign-off, we say so and help you get it — we don’t wave it through.
Often paired with
Survey & sizing: clear answers.
- As a working rule, about 80–100 sq ft of shadow-free roof per kW for standard modules and mounting. A 3 kW home system therefore wants roughly 250–300 sq ft of usable area — 'usable' being the operative word, after tanks, staircase rooms, parapets and shading are accounted for. That accounting is exactly what a site survey does.
- A useful average for India is about 4 units (kWh) per kW per day taken across the year — higher in high-irradiance months and cities (Gujarat, Rajasthan), lower in monsoon months and cloudier regions. So a 3 kW system produces roughly 350–400 units a month on average. We model your city's actual profile rather than quoting the national average.
- Because panels in a string behave like a pipeline: shade on one section throttles more than its own share of output, especially with basic inverter configurations. A water tank's shadow crossing the array for two hours daily can cost a disproportionate slice of annual generation. Survey-stage shadow analysis — including how shadows move across seasons — is the cheapest fix solar has.
- Usually yes — a typical rooftop system loads roughly 15–20 kg/m² with standard mounting, well within most RCC roofs' capacity. The genuine checks are older or lighter roof structures, elevated structures that add wind loading, and waterproofing membranes that penetrative mounting could damage. We flag when a structural engineer's sign-off is genuinely warranted rather than assumed either way.
- Only with a concrete reason — an EV arriving, an AC being added, a floor being built. Oversizing 'just in case' buys capacity the subsidy doesn't cover (CFA caps at 3 kW) and net metering rewards weakly if you export heavily at poor terms. Our design states its consumption assumptions explicitly, so 'future-proofing' is a decision you make with numbers, not a slogan a vendor uses.