Jane Powerson LED bulbs
Last week we discussed compact fluorescent lamps (CFLs) in this column. So today, it's only fair that we give a little space to LEDs, or light-emitting diodes - another form of low-watt illumination.
There is much heat generated by those who argue the relative merits of one over the other. But heat, of course, is exactly what both CFLs and LEDs don't produce (at least in comparison to old-fashioned bulbs with a tungsten filament), and that is what makes them more energy-efficient. LEDs use approximately one-tenth of the amount of electricity as incandescent bulbs to emit an equivalent amount of light - so they are less costly to run, and have a much lighter carbon footprint. The bulbs can last many years (between 30,000 and 100,000 hours), so ultimately they create less landfill and less labour in replacing burned-out bulbs (the latter may be an important factor in offices or other businesses). Our newer traffic lights use LEDs: they are more reliable, and are easier to see in bright sunlight.
LEDs are expensive: €30-€50 for a bulb to fit a GU10 or a MR16 fixture (the small, cup-like, reflective, halogen bulbs used in down lighters and the like). Yet, because of their long life and low wattage this outlay is recouped after a year or two - depending on how many hours they are turned on per day.
LEDs light up when electricity is passed through a semiconductor material, and the resulting movement of electrons causes photons (little particles of light) to be released. The diode and the terminal pins are encased in a tiny, but sturdy, tubular, plastic case where the light is bounced off the sides and out through the rounded tip - producing a directional, rather than a diffuse illumination. This makes LEDs suitable for areas where a narrow spread of light is required, such as over kitchen worktops, at foot-level on stairways, or for a bedside light where one partner is a reader and the other is a sleeper.
At present there isn't a satisfactory LED bulb suitable for a traditional fitting, unless you've no objection to the industrial look (and you'll probably have to buy it over the internet, as I can't find an Irish supplier). Yet the technology is developing rapidly, and an aesthetically pleasing bulb is, no doubt, being designed as you are reading this.
There is one glaring problem, however, with this kind of lighting. Because a well-made, flawless LED bulb can last a lifetime, the scarcity of repeat orders would put manufacturers out of business.