Lighting energy efficiency

There are three main types of lamp, each of which creates light differently:

• filament lamps - the filament has a high resistance to electricity and produces light when it gets so hot it glows
• discharge lamps - an electrical charge applied to a gas-filled lamp makes the gas produce energy in the form of light
• LEDs (light emitting diodes) - a pure semi-conductor produces light in response to an electrical current

Different lamps produce light in different ways and suit different tasks. When you design or refurbish a system, choose the lamp type that gives the right light quality at the lowest lifetime cost.

In most business settings, LEDs are now the first option to assess because they are efficient, controllable and long-lasting. Legacy lamp types may still appear in older installations, so plan upgrades carefully.

Filament lamps

Traditional filament lamps (incandescent and many halogen types) switch on instantly and can render colour well, but they are usually inefficient and expensive to run.

If you still use them for spotlighting or display, check whether an LED replacement would give the same effect with lower running costs and less heat.

Discharge lamps

Discharge lamps include fluorescent and some high-intensity lamps (such as sodium and metal halide). They can be efficient, but many older types are being replaced by LEDs because LEDs are easier to control and maintain.

If you are upgrading, check compatibility with existing fittings and plan safe disposal of old lamps and control gear.

LEDs

LEDs are efficient, switch on instantly and can last a long time when specified well. They work well with dimming, sensors and zoning, which helps you avoid lighting empty areas.

When specifying LEDs for general lighting, check glare control, colour quality and the suitability of drivers and controls.

Energy efficient lamps

If you use fluorescent tubes you can make significant energy savings by switching to slimmer tubes. For example, if you replace T12 tubes (38 millimetres diameter) with T8 tubes (26 millimetres) you can make savings of 10 per cent. Switching to T5 tubes (16 millimetres) brings even greater savings while keeping a high light output.