How to Size a Solar System

Sizing a solar system starts with understanding how much energy you actually use, then working backwards to the panel capacity needed to generate it.

Step 1: Know your monthly usage

Your electricity bill's "units consumed" figure (in kWh) is the best starting point. If you don't have a recent bill, our Electrical Load Calculator can estimate it from your appliances.

Step 2: Factor in peak sun hours

"Peak sun hours" is the equivalent number of hours per day the sun delivers full-intensity sunlight in your location — commonly around 4–6 hours across most of Pakistan, though this varies by season and region.

Step 3: Estimate system size

Roughly, daily energy need ÷ peak sun hours gives an ideal system size in kW, before accounting for real-world losses (wiring, inverter efficiency, temperature, dust) — commonly adding 15–25% extra capacity to compensate.

Step 4: Work out panel count

Divide the adjusted system size by your chosen panel's wattage to get an approximate panel count.

Use our Solar Calculator to run these numbers automatically. Results are estimates for planning purposes only — a qualified solar installer should confirm final sizing, especially for roof space, shading, and inverter selection.