Solar Savings & Payback Calculator

Export earnings: what the grid actually pays back

Solar in Pakistan used to be described as making your meter run backwards. Under net billing, which replaced net metering on 9 February 2026, it no longer does. You sell surplus units at one rate and buy them back at a much higher one.
Two different rates are involved. Units you consume as they are generated save you your full retail tariff – whatever your bill divided by your units comes to, surcharges included. Units you export are credited at the NEPRA buyback rate, the National Average Energy Purchase Price, which is far lower. The current figure is shown in the fine print under your result.
That gap is the whole of net billing economics. It means the return on a solar system is not one number but two blended together, and the blend depends on when you use electricity rather than on how much you generate.
Return on investment therefore improves in ways that have nothing to do with buying more panels:
Shifting load into daylight converts an exported unit into a self-consumed one, and that single change is worth the difference between the two rates – every time.
Higher tariffs raise the value of self-consumption but not of exports, so heavy users see better returns than light users on identical systems.
Oversizing has diminishing returns. Past the point where you cover your own daytime demand, additional panels earn only the buyback rate, and the payback period stretches rather than shrinks.
The calculator above shows the split explicitly – how many units are consumed in the house, how many are exported, and what each is worth – so you can see which half of the return you are actually buying.

Why we ask for your units as well as your bill

Pakistan does not have a single electricity tariff. It has slabs, and the rate climbs as you use more. On top of the per-unit charge sit fuel price adjustments, quarterly adjustments, a fixed charge, meter rent, the TV licence fee and general sales tax.
The result is that two households on the same tariff schedule can be paying very different amounts per unit. Anyone quoting you a flat national average is using a number that is wrong for almost everyone.
Dividing your bill by your units sidesteps the entire problem. It gives your own effective rate, with every slab and surcharge already included, and it needs no assumption from us. Both figures are printed on your bill.
If your effective rate comes out higher than you expected, that is not an error – it is what the surcharges do, and it is exactly why solar pays back faster for heavy users than for light ones.

The number most savings calculators get wrong

This is the section worth reading twice, because it is where most solar quotes in Pakistan quietly overstate the case.
Solar generates in a bell curve peaking around midday. Household demand does not. Fans, air conditioning, lights and cooking load are spread across the day and evening, and a good share of consumption happens after the sun has gone.
So the units your roof produces and the units your house needs do not arrive at the same time. What you use as it is generated saves you the full retail tariff. Everything else is exported to the grid and credited at the NEPRA buyback rate – which is substantially lower than what you pay to buy a unit back.
A calculator that credits every generated unit at your full retail tariff will produce a payback figure roughly half the real one. Ours splits the two, and the fine print under your result shows the split explicitly: how many units are consumed in the house, how many are exported, and what each is worth.

What “payback” means here

The payback figure is the mid-point of the cost band divided by the annual saving. Three deliberate choices sit behind it.
We use the middle of the cost range, not the bottom. Quoting payback against the cheapest possible build is how the industry produces two-year payback claims.
We hold today’s tariff flat. Electricity prices in Pakistan have not historically stayed flat, and every increase shortens your payback. Holding the tariff constant makes the figure conservative rather than optimistic.
We ignore financing. If you are paying in instalments, your cash position is different even though the underlying economics are not.
Treat the result as a ceiling rather than a promise. The realistic outcomes are faster than shown, not slower.

What would make your payback faster

Shift heavy loads into daylight. Running the washing machine, the water pump and the iron between 10am and 4pm converts exported units into self-consumed units, and each one is worth the full retail rate instead of the buyback rate. This is free and it is the single most effective thing most households can do.
Add a battery. A battery stores midday surplus for evening use, pushing self-consumption far higher. It also adds significant capital cost, so it improves the saving and worsens the payback at the same time. Whether it nets out depends on your load shedding, and the honest answer is that most people buy a battery for reliability rather than economics.
Keep the panels clean. A dusty array in Pakistan can lose 10% or more of its output. Cleaning costs nothing but time and directly increases every figure on this page.
Rising tariffs. Nothing you control, but every increase makes the system pay back sooner.

What this calculator leaves out

Fixed charges do not disappear. Meter rent, the fixed charge and the TV fee stay on your bill whatever your consumption. Solar reduces the variable portion, not the whole invoice.
Grid connection is a process, not a switch. Approval involves an application to your DISCO, a bidirectional meter and an inspection. Budget for the time and the fee.
Maintenance is small but real. Cleaning, the occasional connection check, and an inverter that will most likely need replacing once during the system’s life – inverter warranties typically run far shorter than panel warranties, which is worth confirming on any quote.
Degradation is gradual. Panels lose a fraction of a percent of output per year. Over a 25-year life it matters; over a payback period of a few years it does not move the number meaningfully.

Next step

Once you know the size and the saving, the remaining question is which equipment. Panel and inverter prices vary far more than most buyers expect, and the difference goes straight into your payback.