The low-down on downlights
This is an excerpt from an article in Sanctuary magazine issue 4.
Halogen downlights were first designed to spotlight wall paintings but are now used to light up hallways, kitchens and every kind of room to create a “modern” look. But halogen downlights are not only an environmental hazard but can also pose a fire risk if not installed properly.
Energy efficiency
Halogen downlights are a type of incandescent lamp, which works by heating a small piece of metal to white heat to produce light. More than 90 per cent of the energy that goes into common halogen lights turns into heat; as a result the lights use more electricity than needed making them very inefficient.
While halogen downlights are good for direct task lighting as they provide bright pools of light rather than general illumination. Their popularity has exceeded their purpose as they are now being used to light entire rooms. This is achieved by installing a number of lights instead of just one central light source. In fact four halogen downlights are needed to provide the same effective general lighting levels as one 100 watt globe in the middle of a room.
Halogen downlights also use additional energy as they require the use of a transformer that is usually located up in the ceiling above each light fitting. The transformers can use an additional 10 to 30 per cent of the bulb energy, reducing the overall efficiency of the light fitting even further. As the transformers produce heat, if they are installed in the roof cavity, insulation can not be placed near the transformers as it may pose a fire risk. This decreases the effectiveness of the insulation in your roof.
Fire danger
In New South Wales, halogen downlights were linked to 75 house fires in five years. In Victoria there were 57 house fires caused by halogen downlights in 18 months. The fire begins in the roof as the insulation is ignited by the 300 plus degrees Celsius temperatures produced by the light fitting. As the fire is in the roof it often goes undetected by smoke alarms, and residents can be unaware of the fire until it crashes through the roof.
‘Blow-in’ insulation can create dust in the attic space that can act as a accelerant if it comes into contact with high temperature light fittings. Roof space litter or light fittings that are located too close to timber roof members can also start fires.
The wiring rules have changed in response to the number of domestic house fires caused by halogen downlights. New rules require insulation of combustible materials to be kept 200mm from lights and their associated transformers. The distance has increased from 50mm. The new edition of the wiring rules will be published in late 2007. Standards Australia said the new rules should reduce the number of house fires.
