Energy

Lamp selection depends mostly on energy efficiency and the type and amount of lighting required.

On this page:

• Light emitting diodes (LEDs)
• Fluorescent lamps
• Halogen lamps
• Incandescent lamps

The decision of which lamp to use is influenced by:

• energy use
• the amount of light emitted
• lamp purchase cost
• hours of lifetime use
• application, e.g. task/general lighting, short/long periods of use
• colour and temperature of the light required.

In order of lighting efficiency, the available options are: light emitting diodes (LEDs); fluorescent lamps; halogen lamps; and incandescent lamps.

Light emitting diodes (LEDs)

These are very energy-efficient with very low heat output and are extremely long lasting (between 50,000–100,000 hours). They are also expensive and currently cannot provide light to a whole room. At present, they are used for safety lighting and special effects, but LED lighting solutions are one of the most rapidly developing areas of lighting design.

Fluorescent lamps

Fluorescent lamps:

• are very energy-efficient, using as little as 20% of the energy to provide the same light output as an incandescent lamp
• are long lasting (up to 10,000 hours)
• can provide light in a range of colours.

They are not suitable for rooms where they will be used for short periods of time, such as toilets and bathrooms, because they need a ballast to start, which uses more energy than the light itself and causes extra wear. They also take some time to reach full brightness. They tend to be unsuitable for exterior use as they produce less light in low temperatures. Light output will drop slightly as fluorescent lamps age.

Fluorescent tube lamps:

• are available in straight or circular styles
• require special fittings
• are good for background lighting but not for directional lighting
• are most suitable for kitchens, garages and workshops and non-adjustable task lighting
• have a separate replaceable ballast – although electronic ballasts are more expensive, they are more energy-efficient, longer lasting, start the lamp quicker, produce less flicker and are dimmable.

Compact fluorescent lamps are similar to fluorescent lamps but:

• can fit into conventional bayonet or screw-fitting light sockets
• come in a range of styles – stick, globe, circular and square
• can replace incandescent light bulbs in most light fittings
• have an integral ballast
• should be concealed within a fitting to minimise glare.

They are efficient and have a long life (6,000–15,000 hours). They may not be able to be used with dimmers or sensors and electronic switches.

Halogen lamps

Halogen lamps require special fittings and are more expensive than standard incandescent bulbs, but they last longer (up to about 2,000 hours of use). A 35 W halogen lamp produces the same light output as a 50 W standard incandescent. Low voltage halogen lamps (which need a transformer) will further improve energy efficiency but increase cost.

Halogen lamps have a compact filament to produce a concentrated light beam that illuminates a small area, making them suitable for highlighting or task lighting. They are a type of incandescent lamp but provide more light. IRC halogens are more energy-efficient than conventional halogens, with a lifespan of around 5,000 hours.

They are available in two voltages – 12 volt (which requires a transformer) and mains.

When specifying halogen lighting:

• a whiter and brighter light is achieved with 12 V units
• a softer light is achieved with mains powered halogens
• 12-volt systems offer a range of special-purpose bulbs such as wide angle, narrow beam or coloured.

Linear halogen lamps should not be used where the source is visible to the occupants.

New generation halogen lamps look similar to the standard incandescent lamp but will replace it. They use a small halogen bulb encased in a traditional glass globe. They are longer lasting (the life span is approximately twice as long as incandescent) and they are more efficient at converting electricity to light.

They look very similar to incandescent lamps and are also:

• able be used with dimmers, sensors and other electronic switches
• able to produce full light output immediately
• available in a range of shapes.

Incandescent lamps

Incandescent lamps are the same today as when they were first invented by Edison over 100 years ago. They are cheap to buy, but have a short life span (approximately 1,000 hours).