How Much Solar Do You Need for 200 Units a Month?

Short answer: a home that uses 200 units (kWh) a month needs about 1.5 to 1.8 kW of on-grid rooftop solar to cover it over a year, and most families install 2 kW for headroom. A 2 kW system needs about 150–200 sq ft of shadow-free roof, costs roughly ₹1.0–1.4 lakh before subsidy, and qualifies for ₹60,000 central subsidy under PM Surya Ghar (check current notification).

The two-line calculation

Solar sizing in India starts with one number from your bill, units per month, and one number for your city, the specific yield: how many units each kW of panels makes in a year.

1. Yearly units = 200 × 12 = 2,400 kWh
2. System size = 2,400 ÷ yearly yield per kW

Across most of India a well-installed rooftop system makes 1,400–1,650 kWh per kWp per year. The lower end is the Gangetic plain (winter haze), the upper end is Gujarat and Rajasthan.

Yields are long-term averages from Global Solar Atlas, reduced 5% for rooftop losses (Sunlectric Studio data, Oct 2026). Your roof's direction, tilt and shade change the real figure.

Try your own numbers with the sizing simulator:

Why most people choose 2 kW, not 1.6 kW

• Panels come in whole numbers. Modern modules are 540–590 Wp, so 3 modules give about 1.65–1.77 kWp and 4 give 2.2–2.36 kWp. The inverter is usually 2 kW.
• Subsidy steps. PM Surya Ghar pays ₹30,000 per kW for the first 2 kW. Going from 1.5 to 2 kW adds about ₹15,000 of subsidy (check current notification).
• Ageing and dust. Output falls a little every year (about 0.4–0.55% per year for good modules after the first year) and dusty weeks cut it further. A 10–20% margin keeps you covered.
• Consumption grows. A new AC, an induction cooktop or an electric two-wheeler adds 30–100 units a month quickly.

Do not oversize too far. In most states extra units exported to the grid are credited at a low rate (₹2–3.9 per unit, depending on the state), far below what you pay to buy a unit. See net metering explained.

Roof space

A 2 kW system is 4 modules. Each module is about 2.3 m × 1.1 m. Plan for:

• Panel area: about 10–11 m² (110–120 sq ft)
• Total shadow-free roof: about 150–200 sq ft with walkways and setbacks from the parapet
• Shade check: water tanks, staircase rooms, neighbours' buildings and trees. Even a shadow over one module can drag down the whole string.

On a sloped tin or tile roof the modules sit flush, so less space is needed than on a flat RCC roof with tilted rows.

Cost, subsidy and payback

The price range comes from the ₹46,000–70,000 per kW installed range we track for residential systems in 2026. Small systems sit at the upper end per kW because the inverter, net meter, earthing and labour do not shrink much. Run your own numbers in solar payback and IRR explained.

Watch out for free-unit schemes

Several states give free or heavily subsidised units to small users. If your state does, your saving is smaller than "200 units × tariff":

• Karnataka (Gruha Jyothi) and Telangana (Gruha Jyothi): eligible homes get up to 200 units a month free, subject to conditions.
• Tamil Nadu: 200 free units per two-month cycle for homes using up to 500 units per cycle (check current order).
• Rajasthan: 150 free units a month for registered households, with an extra state subsidy for a 1.1 kW system.

In these cases, size for the units you actually pay for, or check whether a smaller system plus the state top-up makes more sense. Our state guides explain each: Karnataka, Telangana and AP, Tamil Nadu, Rajasthan.

Sanctioned load and phase

Most DISCOMs allow rooftop solar up to your sanctioned load. A 2 kW system fits almost every home with a 2 kW or higher sanction. If your sanctioned load is 1 kW, you may need a load enhancement first. A 2 kW system runs comfortably on a single-phase connection.

On-grid, or do I need a battery?

For 200 units a month, an on-grid system with net metering is almost always the best value. It is the only type that gets the PM Surya Ghar subsidy. If you face long power cuts, read do I need a solar battery and on-grid vs hybrid vs off-grid before deciding.

Quick checklist before you call an installer

• Last 12 months of bills (to see the high and low months)
• Sanctioned load and phase (printed on the bill)
• Photos of the roof at 10 am and 3 pm to show shade
• Whether you want the subsidy (needs DCR modules and a registered vendor)

If you are using more than 200 units, see solar for 300 units and solar for 500 units.

Talk to Sunlectric

Send a photo of your latest bill and your roof on WhatsApp to +91 89567 89307 (wa.me/918956789307) and our Solar Desk will tell you the right size for your city. We are a multi-brand distributor, so we can point you to a registered installer near you who buys from us. Want to learn the method yourself? The free Sunlectric Academy sizing module walks through it step by step.

Sources

• PM Surya Ghar: Muft Bijli Yojana, central financial assistance and guidelines: pmsuryaghar.gov.in and PIB scheme document, Aug 2024 (accessed Oct 2026)
• MNRE CFA norms as reported in Sept 2026: SolarQuarter, 1 Sep 2026
• City yields: Global Solar Atlas long-term PVOUT, fetched 19 Oct 2026, derated 5% (Sunlectric Studio data)
• State free-unit schemes and tariffs: Sunlectric tariff notes compiled Oct 2026 from state tariff orders (verify on your latest bill)