Lighting

Lighting for your business

Making changes to the lighting of your buildings and operations can help you reduce energy costs, and in many cases improve the quality and quantity of light. By using energy efficient and effective lighting, energy costs can be reduced by up to 70% in some applications.

How you can save

In general the energy efficiency of your lighting systems can be improved through integration with daylight, selecting energy efficient lamps, luminaires and ballasts, installing lighting controls, improving maintenance procedures and improving the overall design of lighting systems.
The following are some no cost, low cost and investment opportunities for reducing lighting energy costs:

No cost

• Use daylight whenever possible.
• Switch off unnecessary lighting.
• Use task lighting if possible.
• When purchasing equipment always consider the whole life cost (WLC) of lighting systems. The two main elements of WLC are the energy consumption and the maintenance costs.

Low cost

• Maintain light fittings and controls correctly – light levels can fall by up to 50% in few years if light fittings are not regularly cleaned. Also replace discoloured diffusers or fit reflectors. Light output from lamps decreases with age, therefore a replacement cycle should be established.
• Replace T12 (38mm) fluorescent tubes with T8s (26mm), which use 8-10% less energy. Alternatively, the more energy efficient T5 (16mm) tubes can be installed, however, these are designed for use with High Frequency ballasts.
• ‘Standard light bulbs’ (tungsten filament lamps) can be replaced with compact fluorescent (CFLs) with integral ballasts that last eight times longer and achieve savings of 75% in energy. ‘Look-alike’ CFLs are also available.
• Use tri-phosphor coated tubes, which provide a more natural, brighter light during the full lifetime of the tube.

Investment projects

• Check that areas are not overlit, and replace light fittings if economically feasible. This may be more appropriate during refurbishment, but ocassionally may be possible on a low cost basis.
• For external lighting of large areas, high pressure sodium (SON) lamps have a long lamp life and low energy consumption. Alternatively, metal halide (HQI) lamps give good ‘white’ light and have low energy consumption. Low pressure sodium (SOX) is one of the most efficient light sources available but produces a strong yellow light.
• Light switches should be arranged so that they are progressively switched on/off in bands parallel to the windows. Ensure that appropriate zoning is used in all areas.
• Lighting control should be considered wherever possible. These include local switching and dimming, occupancy, daylight linked, time based, and other electronic control.
• On replacing whole lighting systems, make sure to install high-frequency ballasts. These use less energy, ensure longer lamp life, stop flicker and hum, and can allow dimming.
• When designing or redecorating, use light reflecting surfaces.

For more information

Lighting - bright ideas for more efficient illumination (Technology Overview CTV021). Carbon Trust UK http://www.carbontrust.co.uk/Publications/publicationdetail.htm?productid=CTV021&metaNoCache=1

Focus on energy: a practical introduction to reducing energy bills. Carbon Trust UK http://www.carbontrust.co.uk/Publications/publicationdetail.htm?productid=FOCUS&metaNoCache=1

Technical Module on Lighting. The European Green Building Programme.
http://www.eu-greenbuilding.org/index.php?id=203