Peak sun hours vary by location and season, from about 3 in northern Europe to 6–7 in deserts. Lahore averages roughly 5.
How to use the Solar Panel Output Calculator
- System size
- Peak sun hours per day
- System losses
- Electricity price per kWh
Results update as you type, and every field accepts the units shown in its menu.
How it works
System size is multiplied by sun hours, then reduced for inverter, wiring, dirt and temperature losses.
Inputs explained
| Field | What to enter |
|---|---|
| System size | In kW |
| Peak sun hours per day | A number |
| System losses | In % |
| Electricity price per kWh | Amount in your currency |
What each result means
- Energy per day = [System size]×[Peak sun hours per day]×(1 – [System losses]÷100)
- Energy per year = [Energy per day]×365
- Value per year = [Energy per year]×[Electricity price per kWh]
Example values
How the main result changes when System size changes and everything else stays at the example values above:
| System size (kW) | Energy per year (kWh) |
|---|---|
| 2.5 | 3,924 |
| 3.75 | 5,886 |
| 5 | 7,848 |
| 6.25 | 9,809 |
| 7.5 | 11,771 |
| 10 | 15,695 |
Formula
Daily energy = system kW × peak sun hours × (1 − losses)Worked example
Inputs — System size: 5 kW; Peak sun hours per day: 5; System losses: 14 %; Electricity price per kWh: $0.18.
Results — Energy per day = 21.5 kWh; Energy per year = 7,848 kWh; Value per year = $1,412.55.
Frequently asked questions
What are peak sun hours?
The equivalent hours per day of 1,000 W/m² sunlight.
Where can I get local solar data?
NREL’s PVWatts tool gives estimates for any location.
What formula does the Solar Panel Output Calculator use?
Daily energy = system kW × peak sun hours × (1 − losses).