LED and the Person on The Street

The arguments for switching to LED bulbs have been settled. The bottom line is that they have an average lifespan of between 15 and 20 years and in the long run are a sensible and logical investment. Perhaps the biggest hurdle to overcome in the uptake of LED bulbs is their upfront cost. It cannot be denied that LED bulbs come with a hefty price tag as compared to incandescent and halogen bulbs. This is a definite obstacle that needs to be circumvented at a national level if LED bulbs are really to meet their potential.  So, aside from the upfront price what are the other considerations in buying LED bulbs?

Appreciate the difference

LED bulbs have different specifications to both incandescent and halogen bulbs. For the bulbs we are used to buying the Wattage (or Watts, W) number gives an indicator of how luminous the light bulb will be. In short, a 60W bulb will be brighter than a 40W bulb. This is not the case with LED bulbs and the reason is that with LED bulbs wattage is not correlated to brightness. The whole point about fitting LED bulbs is to produce an equivalent luminosity by transferring less energy than alternative light bulbs. In general terms an LED bulb uses between 8-12 watts to produce the luminosity of a standard 60W incandescent bulb.

The key word here is luminosity which is derived from a unit of measurement termed the lumen (lm). The lm number is the actual measured brilliance of the bulb. In other words start thinking in terms of lm units and not watts. As a starting point, a standard LED bulb converts approximately 6 times less electrical energy for a given lm number as compared to incandescent bulbs and the difference continues to increase.

Colour and Kelvin

Although the range of LED colours is expanding almost daily, most of us will be looking for the equivalent white or yellow hue produced by the bulbs we are more familiar with. Having said that, if you are having party or holding an outdoor event there are plenty of alternative colour schemes and light fittings available. In terms of ordinary white LED bulbs, look for the kelvin number (K). This is physical term which for our purposes relates colour to temperature, the lower the number the more “yellow” a white light will appear.  In terms of numbers you are looking for a K number of between 2,700 and 3,500.


In traditional electrical circuits dimming works by reducing the amount of electricity which reaches the bulb. This can present a problem because LED bulbs are not always suited to the installed dimming switches. There is no direct correlation between luminosity and electrical energy converted to light energy and this means a degree of detective work is necessary before walking into the retailer.  Either LED bulbs which will work with the currently installed dimmer system are necessary, or this will need to be replaced.

The benefits of LED bulbs are clear and present but before it is strongly advised that you investigate and inform yourself with knowledge before you and replace your existing bulbs.

Write a Comment