Explicit checks passed
1 explicit check passed for the entered values. This does not replace independent verification where the decision is safety-critical, contractual, statutory, financial or medical.
1 pass
🌅
Peak Sun Hours
Convert daily insolation to Peak Sun Hours.
PerformanceCore inputs only — quick sizing with engineering defaults.
Inputs (SI units)
GHI is measured on a horizontal surface and is NOT the same as tilted plane-of-array irradiation.
Results
✓ PASS — 5.2 h/day is a realistic PSH value.
Solar PV decision support
PV design decision summary
This section organises the existing calculator output into design checks, governing criteria and comparison cases. Core solar formulas and the calculator's original results are unchanged.
Governing criterion
Plane-of-array / entered daily insolation
5.2 h/day
Peak sun hours are the daily irradiation energy divided by the 1 kW/m² STC reference irradiance.
Design checks
Solar engineering check 1
pass✓ PASS — 5.2 h/day is a realistic PSH value.
Structured directly from this solar calculator's own runtime alert.
Next design actions
Engine recommendation 1
Sunshine/daylight duration is NOT peak sun hours — PSH is an energy-equivalent metric, not a time-of-day count.
Engine recommendation 2
Engineering-grade preliminary calculation. Final design must be verified against project-specific site conditions, manufacturer datasheets, applicable standards and utility requirements.
Primary design output
5.2 h/day
Use as a preliminary result and verify the project-specific limits listed below.
Scenario comparison
Lower and higher cases are recalculated by the same solar calculator engine. They are comparison cases, not weather forecasts or guaranteed production values.
Lower daily insolation
daily insolation = 4.16
- Peak sun hours
- 4.16 h/day
- Annual equivalent
- 1,518 h/yr
Current inputs
daily insolation = 5.2
- Peak sun hours
- 5.2 h/day
- Annual equivalent
- 1,898 h/yr
Higher daily insolation
daily insolation = 6.24
- Peak sun hours
- 6.24 h/day
- Annual equivalent
- 2,278 h/yr
Decision sensitivity
daily insolation · up
For the same calculator engine, the lower case changes Peak sun hours by -20.0% and the higher case by +20.0%.
This is a deterministic input sensitivity check, not a statistical uncertainty or weather forecast.
Methodology & limit
Decision support is structured from the existing solar calculator engine and the current user inputs. PASS/FAIL is shown only where the engine or entered project criteria support an explicit check. Final PV design still requires site survey, exact module/inverter datasheets, structural/electrical design and applicable statutory approval.
Engineering Recommendations
- →Sunshine/daylight duration is NOT peak sun hours — PSH is an energy-equivalent metric, not a time-of-day count.
- →Engineering-grade preliminary calculation. Final design must be verified against project-specific site conditions, manufacturer datasheets, applicable standards and utility requirements.
Detailed Calculation Log
Input is already plane-of-array (POA) irradiation — used directly. Daily irradiation 5.2 kWh/m²/day → PSH 5.2 h/day.
Save & Load Project
Designs are stored privately in this browser — nothing is uploaded.
Engineering Formula
- PSH = Daily insolation / 1000 W/m²
PSH is the equivalent hours per day at STC irradiance (1 kW/m²). Kolkata ≈ 4.5, Jaipur ≈ 5.8, Ladakh ≈ 6.5.
Step-by-step Calculation
- 1.POA irradiation
G_POA = G × transposition5.2 kWh/m²/day - 2.Peak sun hours
PSH = G_POA / 1 kW/m²5.2 h/day - 3.Annual equivalent
PSH × 3651,898 h/yr
How to use this calculator: Peak Sun Hours
Convert daily insolation to Peak Sun Hours. The example below is calculated by this page's real engine from the displayed inputs.
- 1Confirm that the Peak Sun Hours matches the quantity or design check you need.
- 2Enter Daily irradiation using the units printed beside each field.
- 3Select the applicable Input mode and Irradiation type entered options; these choices change the calculation method or factors.
- 4Calculate, then follow the substituted equations in the worked example and compare the result with any stated limit.
- 5Read the assumptions, warnings and cited references before using the result for a financial, medical or engineering decision.
Input guide and example values
Use values from the same measurement basis and time period. Conditional fields appear only when the related option is selected.
| Input | Example value | Why it matters |
|---|---|---|
| Input mode | Single daily average | Select the option that matches the real installation or scenario. |
| Irradiation type entered | Plane-of-array (POA) | GHI is measured on a horizontal surface and is NOT the same as tilted plane-of-array irradiation. |
| Daily irradiation | 5.2 kWh/m²/day | Measured or known daily irradiation used by the calculation engine. |
Formula inputs & variables for Peak Sun Hours
These are the named quantities used by this calculator. When the source formula does not define a mathematical symbol, OneCalcApp keeps the real input label instead of inventing one.
| Variable / input | Unit | Meaning in this calculation |
|---|---|---|
| Input mode | — | Select the option that matches the real installation or scenario. |
| Irradiation type entered | — | GHI is measured on a horizontal surface and is NOT the same as tilted plane-of-array irradiation. |
| GHI→POA transposition factor | - | Multiplier applied to GHI to approximate POA at the installed tilt; edit for your latitude/tilt/season. 1.0 = no change. |
| Daily irradiation | kWh/m²/day | Measured or known daily irradiation used by the calculation engine. |
| Jan irradiation | kWh/m²/day | Measured or known jan irradiation used by the calculation engine. |
| Feb irradiation | kWh/m²/day | Measured or known feb irradiation used by the calculation engine. |
| Mar irradiation | kWh/m²/day | Measured or known mar irradiation used by the calculation engine. |
| Apr irradiation | kWh/m²/day | Measured or known apr irradiation used by the calculation engine. |
How the Peak Sun Hours works
The Peak Sun Hours uses Input mode, Irradiation type entered, and Daily irradiation to calculate Peak sun hours and Annual equivalent. Its engine applies PSH = Daily insolation / 1000 W/m²; the worked values below come from that same live calculation rather than a separately typed example.
With Input mode Single daily average, Irradiation type entered Plane-of-array (POA), and Daily irradiation 5.2 kWh/m²/day, the main worked-example result is Peak sun hours = 5.2 h/day.
How each Peak Sun Hours input is used
Input mode
The Peak Sun Hours worked example selects “Single daily average”. Available choices include Single daily average and 12 monthly values. This selection may change the method or factor used by the engine, so choose the option that matches the real case.
Irradiation type entered
The Peak Sun Hours worked example selects “Plane-of-array (POA)”. Available choices include Plane-of-array (POA) and Horizontal (GHI). This selection may change the method or factor used by the engine, so choose the option that matches the real case.
Daily irradiation
The Peak Sun Hours worked example uses Daily irradiation = 5.2 kWh/m²/day. This value is passed directly into the calculation, with an allowed minimum 0.5 and maximum 9.
Peak Sun Hours formulas and result interpretation
Formula 1: relationship used
In the Peak Sun Hours, PSH = Daily insolation / 1000 W/m². The quantities in this relationship come from the named inputs or from an earlier calculation step shown in the worked example.
Peak sun hours
For the displayed Peak Sun Hours worked example, Peak sun hours is 5.2 h/day. Verify Input mode, Irradiation type entered, and GHI→POA transposition factor and their units before relying on this output.
Annual equivalent
For the displayed Peak Sun Hours worked example, Annual equivalent is 1,898 h/yr. Verify Input mode, Irradiation type entered, and GHI→POA transposition factor and their units before relying on this output.
Peak Sun Hours accuracy, checks and limitations
- Peak Sun Hours units check: confirm Input mode, Irradiation type entered, and Daily irradiation (kWh/m²/day) before calculating.
- Peak Sun Hours result check: compare Peak sun hours and Annual equivalent with the substituted formula steps and the displayed rounding precision.
- Peak Sun Hours: Use this result for preliminary design and cross-checking. Confirm the applicable code edition, manufacturer data, site conditions and qualified-engineer approval before final design or installation.
Understanding the result
Read the main result together with supporting checks, assumptions, limits and intermediate values.
For a manual check, repeat the first equation, confirm the units and change one input at a time.
Common mistakes when using Peak Sun Hours
- Do not mix units for Daily irradiation (kWh/m²/day). A unit mismatch changes the input magnitude even when the typed number looks reasonable.
- Do not leave Input mode on the default choice unless that choice matches the real scenario; the selected option can change the calculation path or factor.
- Do not replace the displayed PSH = Daily insolation / 1000 W/m² relationship with a different convention without also changing the underlying assumptions; compare like-for-like methods when checking the result.
- Do not treat Peak sun hours = 5.2 h/day from the worked example as a universal answer. It belongs to the displayed example inputs and must be recalculated for the actual case.
When the Peak Sun Hours is useful
Peak Sun Hours is designed for cases where Input mode, Irradiation type entered, Daily irradiation are known and you need Peak sun hours, Annual equivalent. The page keeps the live calculator, calculation method and worked example together so the result can be checked instead of treated as a black-box number.
Use the calculator for the scope described by its inputs and notes. The displayed method is PSH = Daily insolation / 1000 W/m². If the real project or decision needs factors that are not represented here, treat the result as an estimate and add the missing checks separately.
Input mode and Irradiation type entered: what changes the answer
The worked example uses Input mode = Single daily average, Irradiation type entered = Plane-of-array (POA), Daily irradiation = 5.2 kWh/m²/day. With those values, Peak sun hours is 5.2 h/day. Changing an input should be interpreted according to that field's unit, range, option and hint rather than by the number alone.
For this calculator, the main input roles are: Input mode: Select the option that matches the real installation or scenario. Available choices include Single daily average, 12 monthly values. Irradiation type entered: GHI is measured on a horizontal surface and is NOT the same as tilted plane-of-array irradiation. Available choices include Plane-of-array (POA), Horizontal (GHI). Daily irradiation (kWh/m²/day): Measured or known daily irradiation used by the calculation engine.
How to sanity-check a Peak Sun Hours result
Start by confirming the entered values and units, then compare the substituted working with the displayed formula or calculation steps. Pay particular attention to Peak sun hours, because it is the first worked-example output shown by the live engine.
Finally, compare the result with the assumptions, warnings and related calculators on this page. A nearby calculator can be useful as a cross-check when it measures the same workflow from a different input or output direction.
Next logical calculator
Continue with Solar Generation Calculator
Useful next check because both tools use Jan irradiation and Feb irradiation, while Solar Generation Calculator answers a different part of the same workflow.
Open Solar Generation CalculatorStandards, source trail and limitations
References show the method used. Check the current local edition, amendments and project specification before a regulated decision.
Design Assumptions
- • Daily insolation on plane of array (POA).
Engineering Tips
- ◆Use TMY data averaged over 10+ years for bankability.
Warnings
- ▲GHI ≠ POA — tilt correction can shift PSH by ±10%.
Standards & References
NASA POWERNREL NSRDB
Related Solar Calculators
Azimuth Deviation Loss
Annual energy loss vs deviation from true south (N-hem).
Shading Loss
Annual generation loss from partial shading.
Temperature Loss
Power derating from cell temperature above STC 25 °C.
Irradiance → Energy
PV energy produced from measured irradiance.
Monthly Yield Split
Distribute annual generation across months (India typical).
Panel Degradation
Capacity remaining after N years at given degradation.
Related Engineering Articles
Deeper reading on the engineering behind this calculation.
PV System Size Calculator: How to Calculate the Right Solar PV System Size
The full PV sizing chain — load, peak sun hours, performance ratio, required DC capacity, module count, inverter capacity and DC/AC ratio — with worked equations.
Read Article →How Many Solar Panels Do I Need? Complete PV Module Sizing Guide
Turn your electricity bill into a panel count: load, required DC capacity, module wattage, inverter sizing, plus illustrative examples from 3 kW to 1 MW.
Read Article →Solar PV Performance Ratio (PR): Complete Guide to PV System Losses
What performance ratio means, every loss term from temperature to availability, how the losses multiply, and how PR differs from efficiency and capacity factor.
Read Article →How to Size a Solar PV System Correctly
A step-by-step engineering walkthrough covering load assessment, peak sun hours, performance ratio and module selection.
Read Article →