Solar savings calculator
Rooftop solar in Pakistan is decided by three numbers: how much your array generates, how much of it you consume while the sun is up, and what the rest is credited at when it goes to the grid. Change the third and the economics change completely — which is why the export rate here is an input rather than a fixed assumption. For the rules behind it, read the net metering guides.
Your system and your usage
The daylight share matters more than anything else here. A household where nobody is home until 7 pm exports most of what it generates and depends entirely on the credit rate; one running an air conditioner through the afternoon uses its own generation and is far less exposed to changes in the net-metering rules.
Estimated position
Rs 16,480 / month saved
- Generation573 units / month
- Used directly (never touches the meter)201 units
- Exported to the grid373 units
- Still imported from the grid499 units
- Consumption offset29%
- Bill before solarRs 27,680
- Bill on remaining importRs 18,653
- Export creditRs 7,453
- Net bill after solarRs 11,200
- System costRs 800,000
- Simple payback4 years
Generation assumes a 78 per cent performance ratio, which allows for inverter losses, heat derating, dust and wiring. Payback is simple — it ignores tariff inflation, panel degradation of roughly half a per cent a year, inverter replacement in year ten or so, and any financing cost. Fixed charges, meter rent and the television fee continue regardless of generation.
Generation: peak sun hours, then a reality discount
Peak sun hours is the daily solar energy at a location expressed as equivalent hours at full rated output. Pakistan is well placed — most of the country sits between 4.6 and 5.6, against roughly 2.5 to 3 in northern Europe.
A nameplate kilowatt does not deliver a nameplate kilowatt-hour, so the calculation applies a performance ratio of 78 per cent. That covers inverter conversion loss, output falling as panels heat past 25 °C, dust accumulation between cleanings, wiring loss and module mismatch. On a well-maintained modern system the true figure may be a little higher; on a dusty roof in Multan that goes unwashed through a dry season it is lower.
The self-consumption share is the number that matters most
Electricity you consume the instant your panels make it never crosses the meter at all. It is worth the full retail rate you would otherwise have paid, including every surcharge and the sales tax on top of them.
Electricity you export is worth only the export credit rate, which is set by regulation and has been revised. If most of your generation leaves the house, your investment is exposed to future changes in that rate; if most of it is consumed on site, it is not.
This is the practical argument for shifting laundry, ironing and pool or water pumping into daylight hours after installing solar. It converts export at the credit rate into self-consumption at the retail rate.
Why annual, not monthly
Generation peaks in the long days of May and June and falls sharply in December and January, while consumption in most Pakistani households peaks in summer too — which is a fortunate alignment.
Surplus banked through the strong months draws down through the weak ones. A December bill on a net-metered house tells you almost nothing; the twelve-month position tells you everything.
What simple payback leaves out
It ignores tariff inflation, which works in solar's favour, and panel degradation of roughly half a per cent a year, which works against it. It ignores the inverter replacement most systems need around year ten, and any financing cost.
It also ignores the fixed charges, meter rent and television fee that continue on a net-metered connection regardless of how much you generate. A bill does not go to zero even when the energy charge does.
Frequently asked questions
What size solar system do I need for my house?
Start from your monthly units. Divide by 30 for a daily figure, then by the peak sun hours for your region, then by 0.78 for the performance ratio — that gives the kilowatts needed to cover consumption entirely. NEPRA also caps system size against your sanctioned load, so check that before ordering anything.
Is net metering still worth it in Pakistan?
It depends heavily on the export credit rate in force and on how much of your generation you consume directly. Model both in this calculator with the current rate rather than the rate that applied when a neighbour installed their system — the terms have been revised.
Do I need batteries?
Under net metering, no — the grid does the storing. Batteries make sense where load shedding is severe enough that backup is needed for its own sake, but they add substantial cost and their own round-trip losses, and they do not improve the net-metering arithmetic.
Will solar eliminate my electricity bill?
It can eliminate the energy charge in a good month, but fixed charges, meter rent and the television fee are not consumption-linked and continue regardless. A bidirectional meter also carries a higher meter rent than a standard one.
Related
A model, not a quotation.Installed costs, export credit rates and tariffs all change, and the terms in force on the date of your net-metering agreement are what will govern it. Treat this as a way to test whether an installer’s numbers are plausible, not as a substitute for a site survey.