Before comparing 3 kW and 5 kW packages, put your electricity-use information on the table. A good proposal should explain why a capacity suits your home, rather than relying only on the number of bedrooms or a bill amount.

Read the units and the billing period.

Find the electricity-consumption figure, usually shown in units or kWh, and the dates covered by the bill. Keep the amount payable as context, but do not use it as a substitute for consumption.

For a simple planning example, a bill showing 600 units across two months represents about 300 units per month. It does not mean that the household needs a 600-unit monthly solar estimate. This arithmetic is a way to organise the discussion, not a solar-generation forecast.

Bring several recent bills if you can. A single period may include visitors, an unusually hot spell, an empty house or other changes that do not reflect normal use.

Explain when the home uses electricity.

Write a short list of the loads that matter: air conditioning, water heating, cooking, pumps, refrigeration or EV charging. Add when they usually run and whether you expect the pattern to change.

Two homes with similar monthly consumption may have different operating priorities. Your installer needs to hear about planned appliances as well as the equipment already in use. Ask the proposal to state the assumptions it uses.

Let the roof shape the proposal.

Usable roof area is more than the outline visible in a photograph. Trees, tanks, access routes, roof condition and the proposed mounting arrangement all affect the available layout. Roof age and shading deserve attention before equipment is ordered.

Ask for a panel layout that shows where the array will sit and how the roof remains accessible. If roof repairs are due, discuss the sequence of work first. A fixed square-feet-per-kW shortcut is useful for an early conversation but does not replace a site layout.

Compare 3 kW and 5 kW with the same questions.

Ask each quotation to explain the proposed capacity, equipment models, expected energy range and the assumptions behind it. Check whether the quoted capacity refers to the module array, the inverter or both.

Request a monthly or seasonal generation estimate for your site. Ask how shade, orientation and losses are treated, rather than accepting a single daily-output figure as a promise. Where export is part of the plan, confirm the prevailing utility agreement and billing treatment.

The larger proposal needs a reason you understand: actual demand, a credible future requirement or another documented design objective. More panels are not automatically a better match.

Treat backup as a separate design question.

Tell the installer if essential appliances must operate during a grid outage. A standard on-grid installation normally shuts down when the grid fails. Battery compatibility, inverter operation and the selected backup circuits need explicit discussion.

Read our guide to monsoon generation and power cuts before treating a rooftop system as a backup solution.

Take a useful checklist to the site assessment.

  • Several recent bills with consumption and billing dates.
  • The roof type, site location and any known roof-work plans.
  • A list of major present and planned appliances.
  • A separate list of essential backup loads.
  • Questions about equipment, structure, metering, exclusions and service.

Use the website calculator as an indicative starting point. Ask Hiranya Solar Power for a site-specific discussion and a written proposal you can compare. Check residential subsidy eligibility separately; a subsidy band does not determine the right system size.

Sources and further reading

Research checked on 12 November 2026. Educational guidance supports a site-specific discussion; equipment suitability and applicable utility requirements must be confirmed for the installation.