Sunday, March 2, 2014

Helping You Identify Energy Savings In Lighting

Best way to save energy is to switch to energy saving light bulbs. Best energy saving light bulbs are LED light bulbs.

LED light bulbs can save you up to 75% energy. In chart bellow you can see energy savings and consumption with LED light bulbs versus traditional light bulbs.

Fig 1: Comparison between LED light bulbs and standard light bulbs in energy consumption 


When you switch to LED light bulbs make sure that LED bulbs have minimum required lux value for type of room of task.

In photometry, illuminance is the total luminous flux incident on a surface, per unit area. It is a measure of how much the incident light illuminates the surface, wavelength-weighted by the luminosity function to correlate with human brightness perception.

Minimum recommended light levels in the horizontal plane are shown in the table below for various areas, from AS 1680:1990: Interior Lighting.


Table 1: Minimum recommended light levels

Following this guideline that rooms are not to bright or not bright enough and that light bulbs will not consume more energy than needed, this will equal guarantee energy saving. 

If you already switched to LED light bulbs or other energy saving light bulbs and you are not sure that lux values follows  AS 1680:1990: Interior Lighting than you can use lux meter to measure illuminance levels.

Using the lux meter
Measure lux levels:
  • at table or waist height
  • at four to five different points in each room either:
  • at night (if the room is used at night), or
  • at around one to two hours after sunrise or before sunset.
  • at a time that corresponds roughly to the earliest or latest the room will be used in the middle of winter.
  • If delamping in summer, remember that sun sets earlier and is much lower.


References:
Sustainability Victoria, sustainability.vic.gov.au

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