The South-Facing Myth: Data

Do solar panels have to face south?

The south-facing myth is the most widely repeated piece of solar advice — and it's misleading. PVGIS DATA FOR LONDON (re.jrc.ec.europa.eu): Due South (180°): 1,020 kWh/kWp/yr (100% baseline). South-East (135°): 970 kWh/kWp/yr (95%). South-West (225°): 970 kWh/kWp/yr (95%). East (90°): 820 kWh/kWp/yr (80%). West (270°): 830 kWh/kWp/yr (81%). THE COUNTER-INTUITIVE FINDING: A 4kW east-west SPLIT system (2kW east + 2kW west) produces less total kWh than 4kW south BUT achieves HIGHER self-consumption — because it generates morning (east) AND evening (west) when households are active, rather than peaking at midday when many homes are empty. Financial return from self-consumed kWh (24.5p) is 5-6x higher than exported kWh (4.5p). For a working couple: east-west split can deliver BETTER financial returns than south-only despite lower total generation. Sources: PVGIS solar radiation database, European Commission Joint Research Centre (re.jrc.ec.europa.eu/pvg_tools/en/). All orientation data for London coordinates (51.5°N, 0.1°W) at 35° tilt.