Sizing is where most solar budgets go wrong. An undersized system leaves you paying high tariffs. An oversized system under Pakistan's 2026 net billing rules exports surplus power for only a fraction of what you pay for grid power. Use the calculator below, then read the method so you can check any installer's quote.
Solar system calculator Pakistan: free home solar estimate
Add your appliances, set daytime and night-time hours, and the tool estimates your daily kWh, recommended array size, number of panels, inverter rating and battery capacity.
Solar Load Calculator (Pakistan)
Enter each appliance's power, quantity and daily usage hours. Refrigerators and ACs cycle on and off, so use their average running hours.
Appliance
Watts
Qty
Day hrs
Night hrs
Daily energy–
Monthly units–
Peak load–
Solar array–
Panels needed–
Inverter size–
Battery for night use–
Estimates only. Assumes about 95% inverter efficiency and that all appliances listed may run together for the peak load. Choose the next inverter size up if you run pumps, motors or non-inverter ACs (startup surge). Actual design depends on shading, roof space, sanctioned load and tariff. For a site-specific design, contact Luminey: UAN 0311 1777055.
How do I calculate the load of my solar system in Pakistan?
Follow these five steps. They are the same for a 3 kW home and a 300 kW factory; only the scale changes.
List every appliance you want solar to power, with its wattage. Check the rating plate, the manual or the table below.
Estimate daily usage hours, split into daytime (roughly 9 am–4 pm) and night-time.
Calculate energy: watts × quantity × hours = Wh/day. Add them up and divide by 1,000 for kWh/day.
Cross-check with your electricity bill: monthly units ÷ 30 ≈ kWh/day. Use your highest summer bill if you want year-round coverage.
Find peak simultaneous load: the watts of everything that could run at the same time. This sizes your inverter.
Tip: Your bill is the most reliable data you have. If your calculated kWh is far below your summer bill, you've missed a load, usually ACs, pumps or a geyser.
Electricity load calculator in kW for home: typical appliance wattage
kW vs kWh: kW is power, meaning how much you draw at one moment (sizes the inverter). kWh is energy, meaning how much you use over time (sizes the panels and battery). One kWh equals one "unit" on your DISCO bill.
Typical appliance wattage reference for solar sizing
Appliance
Typical watts
Notes
LED bulb
9–15 W
Ceiling fan (AC motor)
70–90 W
DC inverter fans: 30–40 W
Refrigerator
150–250 W
Compressor cycles; about 8–12 effective hours per day
Deep freezer
200–300 W
1-ton inverter AC
800–1,100 W
Lower once the room is cool
1.5-ton inverter AC
1,200–1,600 W
1.5-ton non-inverter AC
1,800–2,000 W
High startup surge
Water pump (1 HP)
750 W
3× surge at start
Washing machine
400–600 W
Electric iron
1,000 W
Microwave
1,000–1,500 W
LED TV
60–150 W
Desktop PC / laptop
150–250 W / 50–70 W
Solar load calculation formula
These are the formulas the calculator uses, so you can check any quote by hand.
Inverter: 3,080 W × 1.25 = 3.9 kW. A 4 kW unit would be marginal once the pump's startup surge is included, so choose a 5.6 kW hybrid, e.g. Luminey Elecra PV5600
Many installers add a 20% buffer to the array for panel degradation (about 0.4–0.5% per year for N-type modules), dust between cleanings, hotter-than-average summers and future loads such as an extra AC or an EV charger.
2026 caution: under net billing, surplus exports earn only the NEPRA buyback rate (reported at roughly Rs 8–11/unit), against Rs 35–65+ for grid imports. Only add the 20% if the extra energy will be used or stored. Otherwise, put that money into battery capacity. Read more in net metering vs gross metering in Pakistan.
6kW solar system load capacity in Pakistan
A 6 kW array produces about 24–27 units per day (about 720–800 units per month), depending on season and location. In practice, that powers:
What a 6 kW solar system typically covers by scenario
Scenario
What 6 kW typically covers
Daytime (good sun)
2 × 1.5-ton inverter ACs + fans, lights, fridge, pump and TV
Monthly bill offset
Homes using about 700–800 units/month in summer
With 10 kWh battery
Fans, lights, fridge, TV and router overnight, plus about 2–3 hours of one 1.5-ton inverter AC
Small office
6–10 workstations, lighting, 2 ACs, printer and networking during office hours
Load calculator for solar systems: commercial and industrial sizing
Commercial example: office building (weekday daytime load)
Consumption: 150 kWh/day, about 85% between 9 am and 5 pm
Peak demand: 32 kW
Array: 150 ÷ 4.2 ≈ 36 kWp (no buffer, since self-consumption is already high) → about 62 × 585 W panels
Inverter: grid-tied, so the inverter does not need to carry the full peak. Use a 30 kW AC rating (DC/AC 1.2), e.g. 1 × Luminey G3 30 kW or 2 × G2 Pro 15 kW
Storage (optional): Oasis Flex modules to cover evening hours, reduce generator runtime or shave peak-tariff imports
Storage: Oasis 60 (scalable to 3.6 MWh) for peak shaving and maximum demand (MDI) charge reduction
Approvals: systems above 25 kW need NEPRA concurrence, and large systems may need a load-flow study.
For industrial loads, use 15-minute interval data from your MDI meter or energy management system rather than monthly bills, so the design reflects shift patterns and demand peaks. Explore more deployment types on our application scenarios page.
Battery storage capacity calculator: find the right kWh size for your system
Night-time battery sizing guide with suggested Luminey storage
Solar power calculator (kWh) in Pakistan: expected monthly generation
Use this table to estimate units produced per month by system size (average conditions, about 4.2 kWh/kWp/day):
Estimated solar generation by system size
System size
Units/day
Units/month
Units/year
3 kW
≈ 12.6
≈ 380
≈ 4,600
5 kW
≈ 21
≈ 630
≈ 7,700
6 kW
≈ 25
≈ 755
≈ 9,200
10 kW
≈ 42
≈ 1,260
≈ 15,300
20 kW
≈ 84
≈ 2,520
≈ 30,700
50 kW
≈ 210
≈ 6,300
≈ 76,600
Output is higher from April to June and lower in December and January (fog, smog and a shorter day). For a detailed, site-specific simulation, you can also use NREL PVWatts.
Common sizing mistakes
Sizing from the average bill instead of the peak summer bill
Ignoring surge current from pumps, fridges and non-inverter ACs when choosing an inverter
Using nameplate battery capacity instead of usable capacity at the rated DoD
Ignoring roof shading from water tanks and parapets, which can cut a whole string's output
Oversizing for export under net billing
Exceeding sanctioned load, which can get your prosumer application rejected
How many solar panels do I need for my home in Pakistan?
Divide your daily kWh use by about 4.2 to get the array size in kW, then divide by your panel wattage. A home using 18 kWh/day needs about 4.3 kW, which is 8 × 585 W panels.
How many units does a 5kW solar system produce per day in Pakistan?
About 20–22 units per day on average, or roughly 600–650 units per month. Output is higher in summer and lower in winter.
What size inverter do I need for my load?
Choose an inverter rated at least 1.25× your highest simultaneous load. If your ACs, fans, fridge and pump can all run together at 4.5 kW, choose a 5.6–6 kW inverter. Allow extra surge headroom for motors and non-inverter ACs.
How do I calculate battery size for solar?
Battery kWh = night-time kWh ÷ depth of discharge ÷ inverter efficiency. For 8 kWh of night use with a 100% DoD lithium battery and a 95% efficient inverter, you need about 8.4 kWh, so a 10 kWh battery.
Can a 6kW solar system run 2 ACs?
Yes. In good daytime sun, a 6 kW system can run two 1.5-ton inverter ACs along with fans, lights and a fridge. At night, you need a battery sized for the AC load.
Is the load calculator accurate for commercial and industrial buildings?
It gives a good first estimate. For offices and factories, a proper design should use interval meter data, shift schedules, maximum demand, roof structure and tariff (TOU/MDI) analysis.
Should I size my solar system 20% bigger?
Only if the extra energy will be self-consumed or stored. Under Pakistan's 2026 net billing rules, exported surplus earns a low buyback rate, so a battery often gives better value than extra panels.
What is the difference between kW and kWh in a solar calculator?
kW measures power at one moment and sizes the inverter. kWh measures energy over time and sizes the panels and batteries. One kWh is one unit on your electricity bill.
Get a site-specific system design
Calculators give you the right starting point. A final design also needs roof, shading, tariff and sanctioned-load details. Send your last 12 months of bills and your appliance list to Luminey, and our team can recommend matching inverters and energy storage.
