kW (kilowatt) measures power: how fast electricity is being used or produced at a moment. kWh (kilowatt-hour) measures energy: how much is used or produced over time. One kWh is the “unit” on your electricity bill.
What is the difference, in one example?
A 1,000-watt (1 kW) heater running for one hour uses 1 kWh. The same heater running for three hours uses 3 kWh. Power is the rate; energy is the total.
Where each number shows up
| Item | Unit | What it tells you |
|---|---|---|
| Electricity bill | kWh (units) | How much energy you used in the billing period |
| Solar panels | kWp (kilowatt peak) | Panel power under standard test conditions |
| Inverter | kW | The most AC power it can deliver at once |
| Battery | kWh | How much energy it can store |
| Sanctioned load | kW | The maximum power your connection is approved for |
How do kWp and kWh connect?
Panels rated in kWp produce kWh over a day. The Tenzor calculator assumes about 5 peak sun-hours a day and 78% system efficiency, so each kWp makes about 3.9 kWh a day on average. A 3.18 kWp system would make roughly 12 units a day. Your actual figure depends on location, weather, roof direction and shading.
Why this matters when you buy
- Size panels (kWp) from the energy you use: your monthly kWh.
- Size the inverter (kW) to match the panels and your connection.
- Size a battery (kWh) from the loads you want to run during a cut and for how long.
FAQs
Is one unit the same as one kWh?
Yes. One unit on an Indian electricity bill is one kilowatt-hour.
What does kWp mean?
Kilowatt peak: the power a panel or array produces under standard test conditions. Real output is usually lower because of heat, dust and sun angle.