Why there is no single rooftop solar price
Solar installation cost in Kolkata depends on the system you need and the work required at your property. Two quotations labelled “5 kW” can include different panel capacities, inverter specifications, structures, electrical protection and services. A low headline price is meaningful only when the scope is clear.
This guide is a buying checklist, not a current market price list or binding Alif offer. Request a dated, site-specific quotation before making a purchase. State whether your goal is bill reduction, outage backup or both: a battery-backed system is not directly comparable with an ordinary on-grid installation.
Compare DC panel capacity and AC inverter capacity
Ask the supplier to state the total module capacity in kWp and the inverter output rating in kW. For example, ten 540 W modules provide 5.4 kWp of rated DC capacity. That is not the same specification as ten 500 W modules, even if both proposals are discussed as a “5 kW system”. The inverter pairing must be checked against its operating limits and the approved design.
Record module count, wattage, exact model, inverter model and relevant warranty terms. A brand name without a model and equipment schedule is not enough to compare value.
Use a like-for-like quotation checklist
| Item | What to ask |
|---|---|
| Modules and inverter | Exact models, ratings, quantities and written warranty terms. |
| Mounting structure | Roof type, height, material, corrosion protection and design responsibilities. |
| Electrical work | Cable sizes and routes, distribution boxes, protection, earthing and connection work. |
| Installation | Access, lifting, civil work, testing, monitoring and handover inclusions. |
| Approvals | Customer and contractor responsibilities, metering, fees and exclusions. |
| Commercial terms | Taxes, payment stages, validity, change-order rates and maintenance charges. |
Ask whether quantities are provisional. A quotation that assumes a short cable route or a basic low structure can change after survey. The final scope should explain how additional work is approved and charged.
Separate batteries, subsidy and operating costs
A battery changes both the upfront investment and future replacement planning. Compare usable storage, supported loads, autonomy, inverter compatibility and warranty conditions—not simply the battery’s advertised capacity. A request for whole-night backup needs an appliance-by-appliance energy calculation.
Keep gross project cost, any potential subsidy and ongoing costs separate. Do not assume eligibility, approval or the date of payment. Confirm the current scheme and DISCOM requirements before committing; this article does not claim a subsidy amount or approval entitlement.
Budget for the maintenance scope you choose and clarify whether replacement parts, labour, travel and fault attendance are included. Product warranties and an AMC are different commitments.
Check the savings estimate before comparing payback
A financial estimate should show expected generation and how much is used on site. Exported electricity may be treated differently from electricity you avoid buying. Fixed charges and other bill components may remain, even when generation is high.
Ask for the assumptions behind generation, shading, losses and tariffs. Do not accept a guaranteed zero bill based only on panel wattage. Our payback worked example illustrates why self-consumption and export values should be separated.
Prepare for a useful quote conversation
Share recent electricity bills, your approximate usable roof area, safe roof photographs, operating hours and any backup requirement. Mention roof repairs, future floors, access restrictions and whether permission from a landlord or association is needed. Do not climb a roof or open a distribution board to gather information.
Use the solar calculator for an initial estimate, or review our 5 kW planning guide. Then request an itemised Alif solar quotation so the price can be tied to an agreed project scope.