GetSunScore Analysis: Peak Sun Hours
Definition and Solar Context
Peak Sun Hours (PSH) expresses a day's total solar energy as equivalent hours at a constant irradiance of 1,000 watts per square meter (W/m²). It is an energy-equivalence measure, not a count of clock hours at peak intensity.
PSH helps explain why solar output varies by location. GetSunScore's current calculator instead uses committed NLR PVWatts V8 annual AC yields for its supported cities; it does not ingest PSH values directly.
What Does Peak Sun Hours Mean?
A Peak Sun Hour is defined as one hour of sunlight at an irradiance of 1,000 W/m², equivalent to 1 kWh of solar energy per square meter. The concept normalizes variable daily irradiance profiles into a single production-relevant figure.
For example, 5.5 Peak Sun Hours corresponds to 5.5 kWh/m² of daily solar energy. Actual panel output also depends on equipment and system conditions, so PSH alone does not determine household production.
Why Peak Sun Hours Matters in Modeling
PSH can be used in simplified production examples. The current GetSunScore calculator takes a PVWatts annual yield per installed kW for the selected city, then applies its documented low, base, and high production factors.
A higher modeled annual yield can improve a scenario's estimated economics, but the result also depends on consumption, installed cost, self-use, and export value. See the methodology for the actual inputs.
How Peak Sun Hours Applies in Texas
Texas cities differ in their solar resource and modeled PV output. GetSunScore presents city PVWatts annual yield references rather than unverified city PSH ranges.
PVWatts' weather dataset informs the committed annual references. GetSunScore does not add a separate PSH calibration or seasonal adjustment layer to its 20-year scenarios.
Frequently Asked Questions
Peak Sun Hours converts a day's varying sunlight into equivalent hours at 1,000 W/m². For example, 5.5 PSH means 5.5 kWh of solar energy per square meter over that day; it does not mean sunlight stayed at peak intensity for 5.5 clock hours.
The current calculator does not take PSH as an input. It uses committed annual AC production yields per installed kW from NLR PVWatts V8 for each supported city. PSH is useful background for understanding solar resource, not a separate calculator variable.
Solar resource varies across Texas. GetSunScore does not publish city PSH values as current model inputs; its city pages use PVWatts annual yield references instead.
Yes. Clouds affect sunlight reaching a surface. The current GetSunScore calculator does not calculate a daily PSH profile; its committed PVWatts city yields are long-run modeled references, not a current-weather forecast.
Solar Irradiance measures instantaneous sunlight power (W/m²). Peak Sun Hours converts cumulative daily irradiance into a simplified equivalent-hours metric. The two are related: PSH is derived from annual or daily irradiance totals. See the Solar Irradiance glossary entry for additional context.
PSH is explained here as a concept, not published as a current model input. See data sources for PVWatts and EIA snapshot provenance.