How Many Units Does a 1 kW Solar System Produce a Day in Punjab?
Roughly 3.3 to 4 units a day on average, more from March to June and less in December and January fog. The figures we plan with, and what lowers them on a roof.
Updated 15 September 2026
About 3.4 to 4 units a day, averaged over the year. Our calculator plans with 3.4 units per kW per day, after allowing for heat, dust and wiring losses. UTL’s kit sheets quote 4 units a day per kW, which is what a clear, sunny day gives. A 3 kW system therefore makes roughly 10 to 12 units on an average day.
| System | Units a day | Units a month | Units a year |
|---|---|---|---|
| 1 kW | 3.4 | 102 | 1,224 |
| 2 kW | 6.7 | 204 | 2,448 |
| 3 kW | 10.1 | 306 | 3,672 |
| 5 kW | 16.8 | 510 | 6,120 |
| 10 kW | 33.5 | 1,020 | 12,240 |
Where the figure comes from
We start from a yield of about 1,530 units a year per kW of panels in Punjab, before losses. Taking a fifth off for real-world losses gives 1,224 units a year, or 102 a month. We keep it cautious on purpose, so that a customer’s bill comes in at or below our estimate.
Several things lower output on a real roof:
- Heat. Panels lose efficiency as they warm up, and a Punjab roof gets very hot in May and June.
- Dust. A film of dust cuts output noticeably, which is why panels here need regular cleaning.
- Shade. Even partial shade from a water tank or a neighbour’s wall drags down a whole string of panels.
- Direction and tilt. In Punjab, panels facing south at a sensible tilt produce the most.
- Wiring and inverter losses. A small share is always lost between the panels and your meter.
Summer, monsoon and winter fog
From March to June the days are longest and the sun strongest, so generation peaks, even though the heat trims some efficiency.
July to September is uneven. Monsoon cloud cuts some days sharply, while clear days between the rains still generate well.
December and January are the weakest months. The days are short, the sun sits low, and fog and smog settle over the plains. A thick foggy morning can produce almost nothing until the fog lifts, and a hazy week lowers output all day. The cold itself isn’t the problem, since panels actually work more efficiently when they are cool.
Because of that seasonal swing, we size home systems on your bills across the whole year, including your hottest two-month bill.
What this means for sizing
Divide the monthly units you want solar to cover by 102 to get the kilowatts needed. In Punjab the target is often less than your full use, because it is bringing net units under 300 a month that takes the bill to zero. How to size a home system walks through it step by step.
Questions we are asked
Why do some websites say 4 to 5 units per kW per day?
Many of them quote clear-day or before-loss figures, and a clear spring day can come close to that. Averaged over a year, with heat, dust and winter haze, a Punjab rooftop usually lands lower, so we plan with a more cautious figure.
Do solar panels work on cloudy and foggy days?
Yes, but output drops a lot. Thick morning fog can hold generation close to zero until it lifts, and a heavily overcast day produces a small fraction of a sunny one.
How much roof space does 1 kW need?
About 100 sq ft of shade-free roof, which includes the gaps between panel rows for access and to avoid shading.