10 kW solar system — size, output and cost

What this size typically covers

A 10 kW array suits a site consuming in the region of 1200 units a month. That figure comes from a planning assumption of roughly four peak-sun-hours a day in Punjab, derated for temperature, soiling and inverter losses — about 120 units per kW per month.

It is a planning figure, not a guarantee. Real output varies with orientation, tilt, shading, module and inverter selection, ambient temperature, and how well the system is maintained.

Roof area

Approximately 1000 square feet of usable, unshaded area. Assess area honestly: parapet shadows, water tanks, stairwell blocks, and buildings to the south all reduce what is genuinely usable, and a layout that ignores them underperforms from day one.

How many modules is that

Roughly eighteen modules at around 500-550 W each. At this point the array stops being something a roof absorbs incidentally: layout, walkways for maintenance access, and cable routing all become part of the design rather than afterthoughts.

What a 10 kW system typically runs

The size where a large home and a small commercial premises meet. On a house it covers a full domestic load with several air conditioners running through the afternoon. On a shop, clinic or office it covers lighting, cooling, refrigeration, computing and a modest amount of machinery during working hours.

Commercial sites tend to do better out of this size than homes do, for a reason that has nothing to do with the equipment: their consumption happens while the sun is up, so most of what is generated is used directly rather than exported.

Supply and phase

Frequently a three-phase connection, and that changes the engineering. Inverter selection, load balancing across phases, and protection coordination all become live questions, and an unbalanced installation on a three-phase supply causes problems that are easy to blame on the solar system afterwards.

Where the existing board is at capacity — common on premises that have grown load by accretion — the electrical engineering scope is part of the project rather than an optional extra.

With or without a battery

Most 10 kW installations are grid-tied with net metering. Where the site loses money during an outage — refrigeration, a clinic, a workshop mid-process — a hybrid design with a defined essential-loads board is worth the additional cost.

Sizing that battery honestly is the whole exercise: the difference between backing up essential circuits and backing up the whole premises can be several times the price.

Summer, winter and the shape of the year

Output is not constant across the year, and neither is consumption. Generation is highest in the long, clear days before and after the monsoon, and lowest in the short days of winter and under the dust and cloud of the wettest weeks. In this region the summer months combine the highest consumption with strong generation — which is why solar addresses a summer bill more directly than a winter one.

Two consequences worth planning around: a system sized against a summer bill alone will be larger than the year needs, and one sized against a winter bill will disappoint in June. We size against twelve months where the data exists, and say which way we are erring where it does not.

What determines the cost

We do not publish a price for this size, because a credible number depends on things that are only known after a site visit:

• Roof type and the mounting structure it requires
• Distance and route from array to inverter to distribution board
• Condition of the existing electrical installation
• Module and inverter selection
• Whether net metering is included
• Whether battery backup is part of the scope

Market-indicative ranges circulate widely online. They are not our prices, and repeating them here would imply a quotation we cannot stand behind.

If this size is not right

• Around 600 units a month: 5 kW is the domestic workhorse.
• Consistently above about 1,500 units, or running machinery: look at 15 kW.
• Somewhere between the two: the sizing estimator rounds up to the nearest standard size rather than guessing downward.

Next step

Use the sizing estimator to get an indicative size from your own bill or consumption. An engineer verifies the load and the site before any proposal.