Directional variations: north, south, east, or west? – Solar Australia Magazine

The Renewable Energy Testing Initiative’s latest results from solar panel performance testing suggest North-facing panels may not be the most ideal orientation in all scenarios.


One key aim of the Renewable Energy Testing Initiative (RETI) was to better understand how solar panels perform, and more specifically when installed at different orientations – north, south, east and west – to really understand the performance of solar systems facing different directions.

Across the solar industry, it is a common misconception that east and west facing roofs are less efficient resulting in a longer return on investment. However, tests from RETI have produced surprising results in the difference in performance between panels of different orientations. Using data recorded on 26 October 2012, the difference in power production between a north-, east- or west-facing solar system is not as much as most installers would think. Even south-facing panels produced a surprising amount of power.

East-facing panels performed marginally better than West-facing producing 6.849kWh for the day as compared to 6.540kWh respectively. Meanwhile, North-facing panels only produced 6% more power (7.267kWh) for the day – about the same as leaving a plasma TV on during the day. Even South-facing panels produced a reasonable amount of power for the day (6.069kWh), all of which surpass the Clean Energy Council guidelines of 6.3kWh (based on 4.2 peak sun hours for Brisbane).

North-facing panels produce the most kWh and is therefore the preferred orientation for installing solar systems. Over-night temperatures provide for cooler conditions in the mornings for East-facing panels which perform better than West-facing which are exposed to daytime temperatures.

The morning rush is the busiest period for a lot of families getting ready for school and work so an eastern facing system may be more economical following recent changes to the feed-in-tariffs; whereas those who start before sunrise and finish early in the afternoon, and are home for most of the afternoon, may be best with a western facing system.

What is clear is that now that FiTs have been heavily reduced, solar system designers and installers cannot simply face panels north and hope for the best – the focus needs to be put back on the design of the solar system, tailored around the lifestyles of the homeowner, along with better education for the consumer regarding their power usage.

RETI is located at the Brisbane Technology Park in Queensland and is an independent clean energy testing and monitoring facility. Visit for live monitoring and testing results.

Read the full article here.

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