Singing from the same page
Wednesday, October 22nd, 2008In a time where a sustainable environment is on top of the agenda, it is crucial that we all have a common understanding of how technology can contribute to a better environment. With street lighting in mind, it is therefore troubling to find that there is still confusion about the benefits of dimming.
In an article brought in The Press on 16 October 2008, the author, a York-resident, expresses his sincere doubts about how dimming can save energy, thus money. He argues that if he turns his dimmer on at home, he will still be charged the same amount as without a dimmer. Several comments follow from different readers trying to explain the correlation between the consumption of kilowatt-hours and dimming, stating that the author is completely wrong.
However, there is some truth in his claim. Provided that he refers to a standard incandescent light bulb with a traditional home-installed dimmer, the savings in his house would be minimal. Such an installation simply cannot be compared to dimmed street lights as these typically use high pressure sodium (HPS) bulbs and a different dimming system. When lowering the voltage on a HPS bulb during off-peak traffic hours for example, the wattage will decrease by 25-40 percent. The point here is, that you cannot compare traditional incandescent light bulbs in your living room with high pressure sodium bulbs used in street lights in terms of dimming.