Lighten Up

Posted by CESW

Natural Light and Darkness

Artificial lighting consumes energy and 30% of every household’s contribution to CO2 emissions comes from lighting and appliances. Street lighting is also a substantial consumer of energy. If you look at a satellite image of the UK taken at midnight you will see a pattern of urban light visible from a substantial height above the planet. Many people regard this as a form of pollution.

It is argued that too much lighting may affect human health and may cause disruption to animal and plant life. Much lighting is certainly misdirected or excessive. On the other hand, street and security lighting can help community safety.

Sustainable construction should reduce the use of artificial light, maximise the use of natural light, minimise light pollution, but also ensure community safety.

Key Questions

Has the development, including landscaping, been designed to make best use of natural light whilst ensuring that passive solar gains are not excessive?
Have external lights been installed which prevent the emission of light above the horizontal? (eg with full cut-off or ultra low-profile housings)
Have automatic on/off switching systems and intensity controls for internal and external lighting been installed in the building(s)?
Has a policy to use low energy light bulbs been adopted?
Has ‘overlighting’, particularly during night hours, been avoided?

Benefits

Appropriate use of natural light will improve the performance of a building over its lifetime
Energy bills and CO₂ emissions will be reduced
Appropriate, but not excessive, levels of lighting will still provide adequate safety
Use of natural light is likely to provide a better working and living environment and protect human health

Case Studies

Haute Vallee School, St Helier, Jersey - use of wind towers, thermal mass, passive solar heating, external shading and good daylighting (architecture plb - www.architectureplb.com)
O’Sullivan House, Salcombe, Devon - use of natural light and ventilation (Stan Bolt Architect)
Weil Hackett, Mylor Creek - large areas of glazed wall and roof (Poynton Bradbury Wynter Cole Architects)
Tolvaddon Energy Park, Cornwall - use of low energy lighting systems (Contact RDA - www.southwestrda.org.uk)

Sources of Help and Information

BRESCU Guide 1999
Countryside Commission/DETR, Lighting in the Countryside - Towards Good Practice, 1997
Dept. of Transport - ‘Road Lighting and the Environment’
Institution of Lighting Engineers, Guidance Notes for the Reduction of Light Pollution,1997 and Urban Lighting Guide: A Guide to Good Urban Lighting. (n/d)
British Astronomical Association’s Campaign for Dark Skies, Incorporating Lighting Clauses in Your Local Plan
RTPI Introductory Guide to Planning & Environmental Protection at www.rtpi.org.uk/eandp/pub/environment/guide/index.html