An energy efficient ‘passive design’ might imply that the orientation of the building should be such that its main glazed façades face south to benefit from solar heat gains. In fact, for modern buildings where thermal insulation levels are relatively high, solar heat gains to occupied spaces can cause significant overheating. This can result in south facing glazing being heavily shaded, which has a detrimental effect on the daylighting sometimes requiring electric lighting to be used during teaching periods.


Even for older schools solar heat gains can cause overheating. By the time the sun reaches the southerly facing façade, the occupied spaces have been heated by incidental heat from the occupants. Therefore it is usually best to face spaces occupied for longer periods of time to the north which avoids overheating and enjoys good levels of natural lighting. However, there may be benefits from facing unoccupied spaces south or south easterly to take advantage of solar gains in the absence of occupant gains.

Some sites may be exposed to external noise and pollution from traffic. On larger sites this may be a problem at specific locations on the site and at lower floors. Traffic may inhibit the use of natural ventilation for spaces that have polluted and/or noisy aspects. Circulation spaces can be located juxtapose to a road where the impact of noise will be less detrimental than on a classroom environment.

What should I do?

Obtain professional assistance from design consultant to optimise orientation particularly for new build. Consider surrounding use of land and its possible impact.

WLGA - CLILC Llywodraeth Cynulliad Cymru / Welsh Assembly Government