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Replace mercury and sodium vapour lamps


Mercury vapour lamps are part of the high intensity discharge (HID) lighting group. If you have mercury vapour lights on your common property they might be located within large spaces such as the foyers in high rise buildings, in carparks, and most commonly, externally.

Sodium vapour lamps have a distinct yellow colour and are typically used for outside lighting.

Replace with metal halide lamps 

If you have standard 400 Watt mercury vapour lamps then we recommend upgrading to metal halide lamps which typically use 30 - 40 per cent less energy. Ceramic metal halide lamps are less common than quartz metal halide lamps but offer better light quality, less maintenance, and a longer lamp life.

  • The typical payback period would be within 2 - 4 years
  • You can do a straight swap without changing the light fittings
  • A typical lamp will last 10,000 hours and costs about $50
  • You can dim metal halide lamps using ‘multilevel switching’ 

Issues with metal halide lamps:

  • Metal halide lamps require diligent maintenance so ensure the glass is checked for ultraviolet light damage and that the lights are shut down for 15 minutes of cooling every week
  • Like mercury vapour lamps, they are not suitable for areas where you need to switch lights on and off regularly because they need 20 minutes to cool down after they have been turned off (this is called the restrike time)
  • These lamps can take about 15 minutes to warm up and reach their full light output 
  • Dimming or lowering the power within the arc tubes using ‘multilevel switching’ will change the colour blend and compromise light colour

Questions to ask a lighting professional:

  • How often can these lamps be switched on and off?
  • Will I need to group switch these lamps?
  • If I dim these lamps how will it affect the colour?
  • Is the complete lighting system compatible (lamp, ballast, ignitor, fixture and controls)?

Other replacement options for 400 W mercury vapour lamps 

  • Four x 54 Watt T5 fluorescents 
  • New 150 Watt LEDs 
  • 200 Watt induction lamps 

Why replace mercury and sodium vapour lamps? 

  • Mercury and sodium vapour lamps are often more than 20 years old and potentially at the end of their life 
  • Mercury vapour lamps are not energy efficient and suffer poor colour rendering 
  • Sodium vapour lamps are energy efficient but are rarely installed now as metal halide lamps are almost as efficient but deliver better light quality

Mercury vapour lamps contain toxic mercury so you will need to dispose of these carefully because landfill disposal of large amounts of mercury is forbidden in some states.