Solar Glossary

Azimuth

Azimuth is the compass direction your solar panels face, measured in degrees — south-facing (180°) is optimal in the northern hemisphere for maximum energy capture.

Azimuth explained

Azimuth (or solar azimuth angle) refers to the compass direction your solar panels face. It's measured in degrees from north: 0° = north, 90° = east, 180° = south, 270° = west.

In the northern hemisphere (UK, Europe, US, Canada), a south-facing orientation (180° azimuth) captures the most solar energy throughout the day as the sun arcs from east to west via the south. Deviating from true south reduces annual output:

  • South (180°): 100% of optimal output
  • South-East or South-West (135° or 225°): ~95–98% of optimal
  • East or West (90° or 270°): ~80–85% of optimal
  • North-facing (0°): ~50–60% of optimal (not normally recommended)

However, azimuth isn't everything. East-west split systems (half facing east, half facing west) generate a flatter power curve throughout the day, which can actually be more valuable for self-consumption if you use power in the morning and evening rather than at midday.

Many modern homes have east- and west-facing roof slopes with no south-facing surface. An installer should model the actual output for your specific orientation using tools like PVGIS, and a good microinverter or power optimiser setup can maximise output even on sub-optimal orientations.

How this affects your solar decision

Your roof's azimuth directly affects how much electricity your panels will generate each year. Use the Solar Energy Calculator with your roof orientation to get an accurate output estimate.

Enter your roof orientation to see your annual output estimateSolar Energy Calculator

Related terms

Roof Pitch / Tilt AngleRoof pitch (or tilt angle) is the angle of your roof from horizontal — for solar panels, the optimal tilt in the UK is around 30–40°, which matches the angle of the sun's path across the sky.Solar IrradianceSolar irradiance is the power of sunlight hitting a surface, measured in watts per square metre (W/m²), and is the primary factor determining how much electricity your solar panels can generate.Shading AnalysisA shading analysis is an assessment of how shadows from trees, chimneys, neighbouring buildings, and other obstructions affect your solar panels' output throughout the day and year.Solar Panel OutputSolar panel output is the amount of electricity a panel or system produces, measured in watts (W) at peak conditions or kilowatt-hours (kWh) over a time period.
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