Solar System for a Small Shop in Pakistan: Size, Cost and Winter Hours

A small shop is one of the best fits for solar in Pakistan, for one simple reason: a shop is open while the sun is up. A home uses most of its electricity in the evening, after the panels stop producing. A shop uses its lights, fans, fridge and billing machine during the day, exactly when panels produce. That daytime match is what makes shop solar pay back faster than many home systems. But only if the system is sized from the real shop load, not from a guess or from the monthly bill alone.

Step 1: List Everything That Runs in the Shop

Walk the shop and write down each item, its watts, and how many hours it runs while the shop is open. Do not copy a load list from the internet. Your fridge size, your light count and your opening hours are what decide your system.

Worked example for a small general store, open about 10 hours a day:

The fridge figure needs care. A fridge does not draw its full watts all day. Its compressor switches on and off, so the effective figure is lower than the label watts. If your fridge label says 200 W, an effective 120 to 150 W over the day is a reasonable planning figure. When in doubt, note the fridge separately and ask your installer to size from it honestly, not from the label alone.

Step 2: Size the System to Daytime Use, Not to the Monthly Bill

As a rough planning rule, 1 kW of panels in Pakistan produces about 4 to 5 units on a clear day, and less on foggy winter days. For the example shop above, which uses about 5 units during the day, a system of around 1.5 kW covers the daytime load on clear days. A larger system produces more surplus at midday, but surplus only helps if you have net billing or a battery. Without either, midday surplus is simply unused.

This is the most common shop mistake: sizing from the monthly bill. The monthly bill includes evening and night use, which daytime panels cannot cover. Size from the daytime load table in Step 1. Then use the solar load calculator linked below to check your own numbers before talking to any installer.

Step 3: Battery or No Battery? Decide From Closing Time

If your shop closes near sunset, a battery adds cost for very little benefit. Your panels already cover the open hours, and there is almost no evening load left to back up. In that case, a daytime system without a battery, or a small hybrid inverter that can take a battery later, is usually the sensible choice.

If your shop stays open 2 to 3 hours after sunset, especially in winter when darkness comes early, the decision changes. The evening load is mostly lights, which is a small load. A battery sized for lights only is far cheaper than a battery sized for the whole shop. Be clear with your installer about which items the battery must run. A battery quoted for the whole shop costs far more than one quoted for lights and billing machine after sunset. This guide deliberately gives no backup-hours table, because backup depends on battery type, age and load in ways a single table hides. Get the battery size in writing against your own load list.

Step 4: Winter Changes the Shop Calculation in Three Ways

First, days are shorter. The solar window shrinks, so the same system produces fewer units in December and January than in May. Second, fog and smog in Punjab and parts of Sindh cut output further on bad weeks. Third, the shop switches its lights on earlier in the evening, so evening grid use rises at exactly the time generation falls. Expect a higher grid import in December and January, and do not judge your system by December alone. Judge it over a full year.

• Clean panels more often during smog season, because a dusty panel in weak winter sun loses a larger share of its output.
• Keep the freezer door closed and do not overload it during foggy weeks, so the compressor runs less.
• Shift flexible daytime work, such as charging devices or running a small machine, into the midday hours when the panels produce most.

Step 5: Roof, Shade and Permission

Most small shops sit under a house roof or a plaza roof, not a roof the shopkeeper owns. Check three things before ordering.

1. Clear, unshaded space: is there space for the panels, away from the shade of the plaza signboard, water tanks and neighbouring buildings? A signboard shadow across one panel in the afternoon can drag down the whole row it is wired into.
2. Roof ownership: who owns the roof, and do you have written permission to install? A rented shop needs the owner agreement in writing before any drilling starts.
3. Access for cleaning: can the installer reach the panels later for cleaning? Panels nobody can reach are panels nobody cleans.

Step 6: Before You Pay, Get These Five Things in Writing

1. The panel wattage, brand and count, not just the system size in kW.
2. The inverter type: on-grid, hybrid, or hybrid with battery, and what happens during load shedding for your type.
3. The full price split: panels, inverter, structure, wiring, installation labour and net billing application charges shown as separate lines.
4. The warranty papers for panels and inverter, and who to call for a fault.
5. The net billing position: whether your system will export surplus units, and at what terms. Under current net billing rules, exported units are credited at a lower rate than imported units cost, so self-use during the day is worth more than export. Confirm the current export terms with your distribution company before doing any savings math. For the process itself, read the net metering process guide.

Mistakes Shopkeepers Should Avoid

• Do not size from the monthly bill.
• Do not buy a battery for a shop that closes at sunset.
• Do not ignore signboard shade.
• Do not accept a verbal quote with a single lump-sum price.
• Do not compare two quotes by kW alone: a quote with more panels of lower wattage and a quote with fewer panels of higher wattage can both say the same kW while giving different roof needs and different quality.

To check your own numbers, use the solar load calculator and the solar price estimator, and read the winter solar output guide for how winter months affect generation.

Frequently asked questions

What size solar system does a small shop need in Pakistan?

It depends on the daytime load, not the monthly bill. Add up the watts and hours of everything that runs while the shop is open. A small general store using about 5 units a day during open hours needs roughly 1.5 kW of panels on clear days. A shop with a large deep freezer, a photocopy machine or a water cooler will need more. Work from your own load table, not from a neighbour system.

Can a shop run on daytime solar without a battery?

Yes, if the shop closes near sunset. Panels cover the open hours directly, and the grid covers the rest. A battery only earns its cost when the shop has real evening load after sunset, such as lights for 2 to 3 extra hours in winter. For lights-only evening use, ask for a battery sized for lights only, not for the whole shop.

How does winter change a shop solar system in Pakistan?

Winter shortens the solar day, fog and smog cut output on bad weeks, and lights switch on earlier in the evening. The result is more grid import in December and January even though the system is healthy. Clean panels more often in smog season, keep freezer use efficient, and judge the system over a full year, not by one foggy month.

Does a shop need net billing, or is daytime self-use enough?

Daytime self-use alone already saves money, because every unit the shop uses directly is a unit not bought from the grid. Net billing adds value only for midday surplus the shop cannot use itself. Since exported units are credited at a lower rate than imported units cost, self-use comes first and export second. Check the current net billing terms with your distribution company before counting export income in your payback math.

What load should a small shop never put on a small solar system?

Heavy workshop machines such as welders, large motors and commercial heaters do not belong on a small shop system sized for lights, fans and a fridge. They draw sudden high power that can trip the inverter or force the system onto grid power anyway. If the shop runs such machines, tell the installer before sizing, because they change the inverter size and the whole design, not just the panel count.