Solar Payback Calculator (Net Billing)
Simple payback for a solar system in Pakistan under the new net billing rules — not the old, more generous net metering
Frequently Asked Questions
Pakistan's solar rooftop economics changed materially when NEPRA replaced 1:1 net metering with net billing under the Prosumer Regulations 2025 — a shift that affects how much a rooftop solar system actually saves you, not just how the paperwork is structured.
Net metering vs. net billing — the difference that matters
Under the older net metering regime, excess solar energy you exported to the grid was credited at the same rate you'd pay to import electricity — a straight 1:1 swap. Under the current net billing regime, exported energy is instead credited at a separate, generally lower export rate, while imported electricity from the grid is still charged at the full retail tariff — meaning the value of energy you export is now meaningfully less than the value of energy you'd otherwise have bought, which changes the payback math for anyone whose system sometimes exports more than they consume in real time.
A worked example
A household that previously assumed their solar system would offset 100% of imported electricity value through export credits, under the old net metering assumption, will find their actual payback period is longer under net billing — because surplus exported units are now worth less per unit than the electricity they're not importing, not equal to it.
How this connects to your other decisions
Before sizing a system, use the Solar System Size Calculator to right-size it against your actual consumption, city sunlight hours, and available roof space — an oversized system exports more surplus at the lower net-billing rate, which can actually worsen payback rather than improve it, unlike under the old net metering rules where oversizing was less punished. And since this calculator's core savings assumption depends on your current NEPRA tariff, cross-check your baseline bill against the Electricity Bill Calculator first.
Common mistakes
The single most common mistake is running payback numbers using an older net metering assumption — either from an outdated calculator, an installer's boilerplate pitch, or simply not knowing the rules changed — which systematically overstates how much a system will actually save under the current net billing regime. Always confirm which regulation an installer's payback estimate is actually using before trusting the number.