What size solar system do I need? A Pakistan home sizing guide

1Read the units on your bill

Solar is sized from energy (units, or kWh), not from how many appliances you own. Every LESCO, IESCO, MEPCO, K-Electric and other DISCO bill prints a 12-month history of units. That history is the most useful number you have, so copy it into the box below.

2Work out your daily units

Panel output is measured per day, so divide the average from Box 1 by 30.

The daylight share matters more than it used to. A family running ACs, the pump and the washing machine between 9am and 4pm uses most of its solar output directly. A household out all day will export much of it, or will need batteries.

3How much 1 kW of panels makes in Pakistan

Check this for your exact rooftop on the Global Solar Atlas, a free World Bank tool. Click your location, read the PVOUT figure (kWh per kWp per year) and divide by 365.

For central Lahore, the Atlas gives 1,466 kWh per kWp per year, or 4.0 units per kW per day. The monthly figures show why one month tells you little:

Source: Global Solar Atlas long-term average, PVOUT for crystalline silicon at optimum tilt (28°), Lahore city point. Fetched October 2026.

Across the whole country, the World Bank's Global Photovoltaic Power Potential by Country report places Pakistan among countries averaging above 4.5 kWh per kWp per day. That figure includes very sunny parts of Sindh and Balochistan and assumes an ideal ground-mounted plant with only 3.5% soiling loss; a dusty roof will do worse.

4Your kW size, with a quick sizer

Now combine Box 2 and the yield:

For inverter, battery and payback too, use the solar system calculator for Pakistan.

5On-grid, hybrid or off-grid?

Box 3 gives the panel size. What goes around the panels depends on the system type.

6Battery sizing basics

Size the battery for what must run after sunset or in an outage, not the whole house. Multiply each load's watts by its hours. Lights, three fans, a fridge and a router can total 3 units overnight; one AC adds several more.

The divisor is the usable share: lithium is commonly used down to about 10% left, while lead-acid lasts far longer if you use only half. So 3 units of night load needs about 3.3 kWh of lithium or 6 kWh of lead-acid. Brands differ, so check the datasheet.

7Panel count and roof space

Divide the size in watts by one panel's wattage and round up. Panels sold for homes in Pakistan are commonly in the 550–620 W range. A panel of around 585 W measures roughly 2.3 m by 1.1 m, about 28 sq ft; the exact size is on its datasheet.

The 1.3 factor is a working assumption; raised structures over the tank or wider winter row spacing change it. South-facing panels near the Atlas optimum tilt give the most units. For roof dimensions, the marla to square feet calculator helps convert roof dimensions.

8Inverter sizing

• On-grid: pick an inverter close to the panel size. Installers often fit slightly more panel kW than inverter kW (around 1.1 to 1.2), since panels rarely hit their rating in Pakistani heat.
• Hybrid and off-grid: the inverter must also carry your peak load during an outage. Add the watts of everything that runs together, such as two inverter ACs, the fridge, fans and lights, and leave margin for motor start-up.

For net billing, use a DISCO-accepted inverter with anti-islanding protection.

9Net metering rules in 2026

On 9 February 2026, NEPRA notified the NEPRA (Prosumer) Regulations, 2026, replacing the 2015 net metering rules for systems from 1 kW to 1 MW. One-for-one unit exchange gave way to net billing.

As reported by Dawn (10 Feb 2026). NEPRA can revise the buyback rate; confirm it with your DISCO.

After public pushback, two later decisions softened the rules:

• Existing users are protected. NEPRA's amendment SRO 547(I)/2026, reported on 3 April 2026, keeps agreements signed before 9 February 2026 on the old rate and mechanism until they expire. Raising the system's maximum output ends that protection. Applications pending on 8 February also stay on the old rules.
• No licence fee for small systems. On 28 April 2026, NEPRA withdrew the licence requirement and the Rs 1,000 per kW fee for systems below 25 kW, effective from 9 February 2026. Larger systems still pay the fee.

A late-April 2026 NEPRA draft would let DISCOs approve systems up to 25 kW directly. Treat it as a proposal and ask your DISCO who approves your size.

How to apply through your DISCO

1. Check your sanctioned load on the bill. If your planned kW is higher, apply for a load extension first.
2. Hire an installer using DISCO-accepted equipment; get a single-line diagram and datasheets.
3. Apply at your DISCO with CNIC, latest bill, ownership proof (or owner's NOC) and technical documents.
4. Site inspection of the transformer and wiring.
5. Sign the five-year agreement and pay for the bidirectional meter and interconnection work.
6. Meter installation; exports then appear on your bill.

10Worked examples: 300 and 700 units

Both households below are hypothetical, live in Lahore, and use 4.0 units per kW per day with 585 W panels.

This family uses most power in the evening, so on-grid would export much of its afternoon output cheaply; a small battery shifts some to the evening. A home near 200 units should also check protected status, explained in our guide on protected vs non-protected consumers.

If the bill shows a 5 kW sanctioned load, this system cannot connect under net billing until the load is extended. July output is also below May just when ACs work hardest, so expect some monsoon imports.

11Payback: the method, not a price list

Solar prices move with the dollar and duties, so use this method with two or three real installer quotes.

Example with stated assumptions. Take Example B's 5.85 kW system. Assume a hypothetical quote of Rs 900,000, an all-in grid rate of Rs 50 per unit, a buyback rate of Rs 11, and 60% of output used directly. These are assumptions for the arithmetic, not market prices.

• Used directly: 702 × 60% = 421.2 units × Rs 50 = Rs 21,060
• Exported: 280.8 units × Rs 11 = Rs 3,088.80
• Monthly saving: Rs 24,148.80, or Rs 289,785.60 a year
• Payback: 900,000 ÷ 289,785.60 = about 3.1 years

Now change only one thing: the family is out all day and uses just 40% directly. The saving drops to Rs 18,673.20 a month and payback stretches to about 4.0 years. Same panels and price; only the daytime habit changed. It ignores tariff changes and panel ageing. To find your real all-in rate, run a bill through the electricity bill calculator.

12Maintenance that keeps the units coming

• Clean the panels with water and a soft brush, early morning or evening when the glass is cool. Dust is a constant loss in Pakistani cities.
• Watch the inverter app or screen. Compare monthly units with the Atlas figures; a sudden drop usually means dirt, shade or a fault.
• Check bolts, earthing and cables before monsoon and after storms.
• Keep batteries ventilated and out of direct sun; heat shortens their life.

13Common mistakes

• Sizing from the June bill. You pay for panels that export cheaply for eight months of the year.
• Ignoring sanctioned load. Under the 2026 rules your system cannot exceed it, so check before you buy panels.
• Treating 1 kW as 5 units a day. That fits a Lahore spring, not the year.
• Buying a battery for the whole house. Size it for essentials; running ACs all night from storage is costly.
• Assuming old net metering terms. New connections are on net billing, and changing an old system's output can move you onto it.
• Comparing quotes only on price per kW. Ask for model numbers, warranties and who handles DISCO paperwork.