How many units does a solar panel system make per day?
Solar output is counted in units, and one unit is one kilowatt-hour (kWh), the same unit on your electricity bill.
The rule of thumb
In sunny regions a well-installed system makes about 3.5 to 5 units per kW of panels on a clear day. Multiply by your system size:
| System size | Clear day | Typical monthly total |
|---|---|---|
| 1 kW | 3.5 to 5 units | 100 to 140 units |
| 2 kW | 7 to 10 units | 200 to 280 units |
| 3 kW | 10 to 15 units | 300 to 420 units |
| 5 kW | 17 to 25 units | 500 to 700 units |
| 7 kW | 24 to 35 units | 700 to 980 units |
| 10 kW | 35 to 50 units | 1,000 to 1,400 units |
Monthly totals assume a mix of clear and cloudy days. These are estimates, not guarantees: your location, roof direction and tilt change them.
Why your number is lower
- Clouds, haze or smog cut output within minutes.
- Dust and bird droppings on the panels, especially in dry seasons.
- Shade from a tank, a tree or the next building, even on part of one panel.
- Heat: panels lose a little efficiency on very hot days.
- Inverter limits or faults, or a datalogger that stopped reporting.
Compare similar days rather than single readings. A drop on a clear day is the one worth checking.
Track it properly
Helio shows today's units from the inverter's own counter, the day's curve and a 30-day view with your average and best day, so a bad day stands out. See it with sample data or read how to check today's units.
Questions
How many units does a 1 kW solar system make per day?
Roughly 3.5 to 5 units (kWh) on a clear day in sunny regions such as most of India. Cloudy days, haze, dust and shade bring it down.
How many units does a 3 kW system make per day?
Around 10 to 15 units on a clear day, using the 3.5 to 5 units per kW rule.
How many units does a 5 kW system make per day?
Around 17 to 25 units on a clear day. Over a year that averages out lower because of cloudy and monsoon days.
How do I see my real daily units?
Your inverter's display shows E-Today, and its monitoring app shows today's energy. Helio opens straight on that number for Eybond / ShineMonitor systems.
Free and open source. Deploy your own copy in about five minutes.