1kW Solar Panel: How Many Units Per Day? (TN Table)

Short answer: a 1kW solar system produces about 4 to 5 units of electricity a day in Tamil Nadu. That is 120 to 150 units a month and 1,400 to 1,650 units a year. One unit is one kWh, the same "unit" you see on your TNEB bill.

The exact number depends on the season, your town, shading and how well the system is installed. Below is the full breakdown so you can check what 1kW will really do for your home.

1kW Solar Units: Day, Month and Year

These are real-world figures for a shade-free, south-facing system with clean panels. A lab rating of "1kW" does not mean 1kW all day; the sun is strong for only a few hours.

How We Calculate It (So You Can Check Any Quote)

Daily units = system size (kW) × peak sun hours × performance ratio

• Peak sun hours in Tamil Nadu: about 5 to 5.5 on average.
• Performance ratio (losses from heat, dust, wiring, inverter): about 0.75 to 0.80 for a good installation.

So for 1kW: 1 × 5.2 × 0.78 = 4.06 units on an average day, and up to 1 × 5.5 × 0.80 = 4.4 or more in clear summer weather.

If any installer promises 6-7 units a day from 1kW, ask them to show the math. It is not possible on a normal rooftop in Tamil Nadu.

Month by Month: How Season Changes 1kW Output

The northeast monsoon is Tamil Nadu's main rainy season, so October to December gives the lowest output. Summer more than makes up for it, and with a net meter your extra summer units are credited against your bill. Read more in our solar panels in rain and cyclones guide.

By Town: 1kW Output Around Cuddalore

Coastal homes should clean panels more often because salt and dust settle faster. See our maintenance guide.

What Can 120-150 Units a Month Run?

A 1.5 ton AC alone uses 150-250 units a month in summer, so 1kW cannot cover a home with an AC. For that, see can a 1.5 ton AC run on solar.

Is 1kW the Right Size for You? An Honest Answer

1kW makes sense only when:

• Your monthly use is under about 150 units, and
• Your roof is small, or your budget is tight.

But check this first. From May 2026, Tamil Nadu homes using 500 units or less in a two-month bill get 200 units free (earlier 100). If your bimonthly use is already low, much of it is free and 1kW solar saves less money than you might expect. Our TNEB slab rates guide explains this.

For most families, 3kW is the better buy. It produces 12-15 units a day, covers an AC, and gets the maximum ₹1 lakh subsidy (₹78,000 central + ₹22,000 Tamil Nadu top-up). The cost per unit of electricity is much lower than with 1kW. Compare on the 3kW solar system page.

1kW Price and Subsidy (Tamil Nadu, 2026)

Market averages as of October 2026. Your exact price depends on roof, structure height and panel brand; we give a written quote after a free site visit. Subsidy rules: ₹1 lakh solar subsidy in Tamil Nadu.

2kW, 3kW and 5kW Compared

See the full solar units per day table for every size and the 5kW units guide.

Not Sure Which Size You Need?

Send us a photo of your last TNEB bill on WhatsApp (+91 7904369094). We will tell you the right size, the units you can expect and your subsidy, free of cost.