The most useful document in any solar plan is one you already have: your electricity bill. Before you compare panels or inverters, spend five minutes with your last bill. It tells you more about the right system size than any brochure.
1. Units consumed (kWh)
Look for the units used in the month. This is your energy consumption in kilowatt-hours (kWh), and it is what a solar system replaces. Most bills issued by IESCO (Islamabad and Rawalpindi) and other distribution companies also show a 12-month history of units. Use it. Summer months with air conditioning can be two or three times your winter usage, and a system sized on one month alone will be wrong for the rest of the year.
2. Why the rupee total can mislead
It is tempting to divide your bill by a price per unit, but a bill is more than units × rate. Depending on your connection it can include:
- tariff slabs, where the rate changes with how many units you use
- fixed charges linked to your sanctioned load
- fuel and other adjustments
- taxes and duties
So a lower bill after solar is not a straight percentage of the units you generate. Our cost estimator asks for your units where possible, and keeps fixed charges separate, for exactly this reason.
3. Sanctioned load and connection type
Your bill shows your sanctioned load and connection type: single or three phase, residential or commercial. These affect which inverter suits you and whether you can apply to export surplus power to the grid. The rules for exporting power and how it is credited have been revised over time, so always confirm the current terms for your connection before counting on export income.
When does each kind of system make sense?
- On-grid: lowest cost per unit generated, but it switches off during load-shedding.
- Hybrid: solar plus a battery, so essential loads keep running in an outage.
- Off-grid: for sites without a reliable grid connection; batteries are essential.
Try it with your own bill
Take your last bill and open the package builder. Enter your units and per-unit rate, choose a system type, and you will get an indicative system size and cost in PKR. If you live in Rawalpindi, Islamabad, DHA or Bahria Town, send it to us and we will check it against your roof and your full bill history.