What are peak sun hours?

Peak sun hours are the equivalent number of hours per day when solar irradiance averages 1000 W/m².

Are peak sun hours the same as daylight hours?

No. Daylight hours are the total time between sunrise and sunset, while peak sun hours represent equivalent full-strength solar energy.

Peak Sun Hours Calculator | Solar Sun Hours & PV Output Estimator

Peak Sun Hours Calculator

Estimate peak sun hours from solar irradiance, PV array size, daily kWh output, or target energy production.

☀️ Field Rule: Peak sun hours are not daylight hours. They mean the equivalent full-power solar hours at about 1000 W/m². Use this result with the Solar Panel Output Calculator, Solar Battery Bank Calculator, Solar Panel Series/Parallel Calculator, Solar String Sizing Calculator and MPPT Charge Controller Calculator.

🌞 Solar Irradiance Converted to Peak Sun Hours

Daily Solar Irradiation

Panel Tilt / Direction Loss

Shading Loss

Soiling / Dust Loss

Season / Month Note

Output Style

If you have solar radiation data in kWh/m²/day, the numerical value is approximately the raw peak sun hours. Example: 5.5 kWh/m²/day ≈ 5.5 peak sun hours.

Presets:low sun 3.5good sun 5.5very sunny 6.5

Daily Solar Output

Solar Array Size

System Efficiency

Use Case

This mode estimates the effective peak sun hours from a known PV system output: PSH ≈ daily kWh ÷ array kW ÷ efficiency.

Target Daily Energy

Solar Array Size

System Efficiency

Available Sun Hours Optional

This mode tells how many peak sun hours are needed to reach a target daily kWh from a given solar array size.

📐 Formula Reference

From Irradiation

Peak sun hours ≈ kWh/m²/day
Example: 5.5 kWh/m²/day ≈ 5.5 PSH

From PV Output

PSH = daily kWh ÷ array kW ÷ efficiency

Solar Output

Daily kWh = array kW × PSH × efficiency

Needed PSH

Required PSH = target kWh ÷ array kW ÷ efficiency

📋 Quick Reference

Typical PSH

Low sun2–4h

Good sun4–6h

Very sunny6h+

Not Same As

Daylight hoursdifferent

Sunrise-sunsetdifferent

Cloudy daylower

Used For

Panel outputkWh/day

Battery sizingdaily energy

System sizingarray kW

📚 Engineering Notes

Peak sun hours simplify solar estimatesInstead of modeling every minute of sunlight, PSH converts daily solar energy into equivalent full-strength sunlight hours.

Location and season matterPeak sun hours vary by latitude, weather, season, panel tilt and local shading.

Use PSH for output calculationAfter calculating PSH, use the Solar Panel Output Calculator to estimate daily and monthly kWh.

Complete the solar workflowContinue with the Solar Panel Series/Parallel Calculator, Solar String Sizing Calculator, MPPT Charge Controller Calculator and Solar Battery Bank Calculator.

What is a Peak Sun Hours Calculator?

A peak sun hours calculator estimates the equivalent number of full-power solar hours available for PV generation. It is used for solar panel output estimation, solar system sizing, off-grid battery sizing and solar payback calculations.

Peak sun hours vs daylight hours

Peak sun hours are not the same as daylight hours. A location may have 12 hours of daylight but only 4 to 6 peak sun hours because morning, evening, clouds and panel angle reduce available solar energy.

Solar design workflow

Use this page to estimate solar resource first. Then use the Solar Panel Output Calculator for production, the Solar Battery Bank Calculator for storage, the Solar Panel Series/Parallel Calculator for PV wiring, the Solar String Sizing Calculator for voltage safety, and the MPPT Charge Controller Calculator for controller size.

How to calculate solar panel output from peak sun hours

Daily solar output in kWh is roughly equal to solar array size in kW multiplied by peak sun hours and system efficiency. For example, a 5kW system with 5 peak sun hours and 80% efficiency produces about 20 kWh per day.

❓ Frequently Asked Questions

For practical solar estimates, yes. A value like 5.5 kWh/m²/day is approximately 5.5 peak sun hours.

Yes for a planning estimate. For off-grid systems, also check the worst month or low-sun season to avoid undersizing.

Sun angle, day length, cloud cover and weather patterns change during the year, so available solar energy also changes.