Performance and output, 55 tools

Why isn't your system producing what the label says?

Weather, shading, hardware, and age all pull real output below nameplate rating. These tools isolate each factor so you know exactly where your kWh are going.

Start here

The tool most people run first

Real world vs nameplate output gap calculator See exactly how far your actual output falls from the rated number, and why.

Output numbers only help once you know what size system they belong to. The solar panel calculator turns your usage into a panel count, and the cost per kWh produced calculator puts a price on each unit that system makes. For the losses behind these numbers, the US Department of Energy's PV performance report lists temperature, wiring, and mismatch as standard predictable losses, and the EIA's solar energy explained page covers how the electricity itself is generated and used.

Core output figures

How much power should you actually expect

Annual kWh output estimator Monthly kWh output estimator Daily kWh output estimator Quick output estimator Output calculator for a 4 person household Output vs usage gap analyzer Real world vs nameplate output gap

Sun, latitude, and yield

The metrics installers actually use

Peak sun hours calculator Peak sun hours by latitude Seasonal output calculator by latitude Capacity factor calculator Performance ratio calculator Specific yield calculator

Weather and climate

How your local weather cuts into output

Temperature derate calculator Hot climate efficiency loss Cold climate efficiency gain Humidity impact on output Cloud cover output reduction Dust and soiling loss estimator Altitude impact on output Coastal fog impact on output Desert heat impact on output

Snow loss by region

Snow cover cuts output differently by climate

Snow loss estimator, Northeast Snow loss estimator, Midwest Snow loss estimator, Mountain West Snow loss estimator, Canada

Shading

Find exactly what's blocking your array

Shading loss estimator Output loss from partial shading Output loss from tree shading Output loss from chimney shading Output loss from a neighboring building Morning vs afternoon shading impact Seasonal shading variation

Orientation, tilt, and tracking

Compare mounting choices before you decide

Panel orientation output comparison Tilt angle output comparison Tracking vs fixed mount comparison Single axis tracker output Dual axis tracker output Flat roof vs pitched roof output Ground mount vs roof mount output

Panel and equipment choice

See how hardware choices change the output number

Monocrystalline vs polycrystalline output Bifacial vs standard panel output Output variance by panel brand Output calculator with microinverters Output calculator with power optimizers

Faults and equipment loss

Diagnose losses hiding inside the system

Output loss from microcracks Output loss from hotspots Output loss from PID degradation Inverter clipping output loss String mismatch loss calculator Wiring loss output calculator

Output over time

Watch output change across the system's life

First year output estimator Year 10 output estimator Year 25 output estimator 25 year output projection

Questions

Frequently asked

Real systems typically run at 75% to 85% of nameplate rating once you count inverter loss, wiring loss, heat, dust, and shading together. The nameplate gap calculator breaks down exactly where your system loses the rest.

Most panels lose about 0.3% to 0.5% of output per degree Celsius above 25°C cell temperature, which adds up fast on a 95°F roof. The hot climate loss calculator and temperature derate calculator both model this directly.

Yes, tilt helps snow slide off faster but doesn't eliminate the loss, especially after heavy regional snowfall. Check the Northeast, Midwest, or Mountain West tool for numbers specific to your snow pattern.

Most panels degrade about 0.5% a year, so a system rated at 100% in year one typically sits around 95% by year 10 and 87% to 88% by year 25. Compare stages with the year 10 and year 25 estimators.