Solar power is not my occupation nor do I have any installed, but some insights may be possible.

First, too little information. Is this a roof application or field application? Is a roof south facing? Is a "unit" a kWh (kilo-watt-hour)? Is the view of the sky unobscured between zenith and, say, 30 degrees above the horizon. (Pakistan covers a range of latitudes.) Can you sell excess power back to the power utility in the summer to make up for poor performance in the winter? The meaning of "ideal" is also ambiguous. Even on a cost basis one would have to know panel and installation costs along with panel lifetime.

On a daily basis in summer, it is my understanding that a typical panel can generate about 300W when the sun is perpendicular to the plane of the panel. Averaging over the day maybe 2 kWh can be generated. Over a month in June/July maybe 60 kWh can be generated -- per panel.

So you may appreciate that more panels are needed than one if there is room for them. Ten, for example, would yield by this example 600 kWh per month in the summer.

Winter, even without snow, but also without changing the angle of the panels, would yield considerably less. (Output power is proportional to the cosine of the Impingement angle; kWh also is also proportional to duration of solar exposure -- less in winter.)

You may be able to find an on-line calculator that can perform more accurate estimates given a latitude and roof angle.