What are induction lights?
Induction lighting is a technology that has never enjoyed significant mainstream adoption, even though it’s been available for decades. Over the past 5-10 years, induction has increased in popularity, perhaps in response to the increase in LED options and their ability to compete with the long lifespan of LEDs.
Like fluorescent lamps, induction lamps (or electrodeless lamps) are a low pressure source that excites mercury, producing ultraviolet radiation which is then translated into the visible light range by various phosphor coatings on the inside of the lamp. Induction differs from fluorescent in the way that the gas is excited. Fluorescent lamps use electrodes at each end, which provide the ultimate point of failure, whereas induction lamps have no direct electrical contact points, but rather use a magnetic field which induces the appropriate reaction.
When should they be used?
Induction lamps can be an excellent choice for some applications, particularly in outdoor settings when white light is desired. For example, as an exterior wall mount (wall pack) above a door or around a building, or as canopy lights employed to illuminate outdoor, and indoor, parking lots. Technology developments mean that induction lights are now capable of providing light output over a wider range of ambient temperatures, as has been done with compact fluorescent lamps. Installed in an enclosed fixture to keep in heat, induction fixtures are quite capable of providing good light in exterior environments even in Alberta during the winter. This will vary, however, depending on factors such as the manufacturer, wattage, type of enclosure, application, and ambient temperature.
Induction lights are also increasingly being chosen as a more efficient and longer lasting alternative to metal halides. When it comes to lower wattage (175 watts or below) options, induction lights have many advantages over metal halides, including:
- A variety of colour temperatures (warm to cool white)
- Much longer life (especially important in lower wattages, where the lifespan of metal halides average 12,000 hours, compared to 60,000+ hours for induction lights)
- Better lumen maintenance. Metal halide lamps tend to depreciate significantly over their life, upwards of 50 per cent for probe start lamps, whereas induction lamps may depreciate 25 per cent over their much longer life
- Higher efficiency (lumens/watt)
The lack of electrodes means that induction lamps can last for a very long time- 60,000 to 100,000 hours. At the same time they share all other benefits of fluorescents: a range of colour temperatures, excellent energy efficiency, no flickering, quiet operation, white light, instant-on, excellent lumen maintenance (output over life), and good colour rendering. As with all light sources, there are limitations as well: more susceptibility to ambient temperature (i.e. less light output in really hot or cold conditions) and difficulty providing good optical control due to the light being emitted from the surface of the lamp.
There are some applications where induction is not the right choice, for example large area lighting projects or to provide high-intensity accent lighting. Induction lights also tend to be more expensive than metal halides or compact fluorescents, but are often justified through maintenance savings achieved over the long lamp life.
Like all sources, LEDs have inherent strengths and weakness. At this time, the 4’ replacement LED lamps do not provide any consistent benefits over fluorescent 4’ lamps, and potentially have negative consequences. Testing of 4’ linear LEDs conducted by the Department of Energy’s Commercially Available Light Emitting Diode Product Evaluation and Reporting (CALiPER) program in October 2010 found that:
