INTRODUCTION TO LED LIGHTING:
LED lighting is now the optimal solution for residential and commercial lighting needs. Due to massive investment over recent years (Philips has spent over $5 billion on the LED market), LED technology has matured to a point where LED bulbs (or ‘lamps’ as they are often called) deliver a truly equivalent light output to conventional incandescent, halogen, or compact fluorescent lamps.
Today’s LED lamps or tubes are strong, durable, and contain no filaments; there is no chance of shattering, breakages, or mercury contamination. Many of the market leading LED lamps have rated lives of up to 50,000 hours (50x longer than a standard incandescent light bulb) and consume up to 90% less energy than conventional lamps. The best way to understand the benefits of LED lighting is to do a cost of ownership calculation: calculate the electricity saving and the costs avoided from not having to replace blown bulbs over the lifetime of the lamp (over 10 years in many cases).
Of course, another strong argument for switching to LED lamps is because it is great for the environment. LED lamps consume up to 90% less electricity which means CO2 emissions get cut by up to 90%. So, you can slash your carbon footprint at the same time as slashing your energy bills!
LED lamp manufacturers have made it easier than ever to switch to LED lighting, by designing LED lamps with the same light output, dimensions, and cap bases as conventional lamps. This makes retrofitting a breeze. In most cases, LED lamps will slot directly into existing fixtures and fittings, and many offer comparable dimming functionality. Customers can select the colour temperature (e.g. warm white, cool white) and beam angle they prefer to match their existing set up.
Designers have also focused on LED lamp aesthetics to ensure they look as good as the conventional lamps they replace. This is especially important for candle or globe bulbs in chandeliers or luminaires, where decorative effect is important. Indeed, Philips has drawn upon inputs from chandelier makers, and intentionally designed their candle lamps to enhance the aesthetic appeal of the chandelier not only when lit but also when not, with classical slender shape and unique eye-catching lens. Quality LED lamps deliver sparkling warm light with huge energy savings and maintenance cost reductions.
You may say that compact fluorescents (‘CFLs’) are a good enough alternative. Let’s take a look: total cost of ownership of CFLs is poor, light quality is harsh (and contains harmful UV radiation), they are bulky (some say ugly!), most are not dimmable, energy efficiency is average, and the big concern is that CFLs contain toxic mercury vapor and are therefore hazardous waste. LEDs will soon overtake low energy CFL lamps as the lighting of choice.
The UK Energy Saving Trust advises that if everybody there changed their lights to LED where possible, we would be able to save enough energy to light 5 million homes! It’s easy to see that LED lamps are the future of lighting.
LED RETROFIT REPLACEMENT STRATEGIES:
Adhoc: you may plan to replace conventional lamps as and when they blow. This strategy is simple and effective, and minimises capital outlay. However, it is more expensive in the long term, because you are delaying the cost of ownership savings for lamps not yet replaced, and cannot take advantage of any volume discounts when buying LED lamps or fittings.
Phased: if capital cost constraints mean you need to replace lamps in phases, then its best to prioritise your lamp stock, based on a ranking of how long they’re switched on. Hospitality business owners will probably have lots of halogens that are on nearly all the time in stairwells, corridors, and lobbies. It’s important that these are replaced first, since this will deliver the largest benefit. Homeowners may find it easiest to adopt a room by room approach, starting off with highly used kitchens and living rooms.
Full retrofit: this approach is the most capital intensive but yields the greatest returns financially, environmentally, and functionally. For large retrofits (typically >200 lamps), lease financing options are available for energy efficient lighting projects (e.g. in the UK, the Carbon Trust makes funding available through its partner Siemens Financial Services). What makes this compelling is that the LED energy cost savings are often sufficient to cover the finance payments, so it becomes a great cost neutral strategy. The lease term will typically be 3 or 4 years, after which time, the customer owns the lamps and fittings. In the meantime, the monthly lease fees simply get paid for out of the energy cost savings.
Lamps are either low voltage (LV = 12V) or mains voltage (MV = 230-240V in the UK). Most quality LED lamps are also dimmable, and will work on the majority of dimming systems, making for a simple swap-out retrofit.
Medium Voltage Lamps:
Lamps with the following bases (or sockets) generally run directly at mains voltage, 230-240V AC (UK):
– SES, E14 and E27 refers to type of screw socket. SES stands for Small Edison Screw, which is the same as an E14 socket (i.e. base diameter or 14mm), which is usually found on chandelier type fittings. E27 sockets are Medium Edison Screw, with a base diameter of 27mm, and are usually found on table lamps, GLS pendants or PAR fixtures.
– B15 and B22 refers to type of bayonet socket. B15 sockets (i.e. base diameter or 15mm) are usually found on chandelier type fittings. B22 sockets, with a base diameter of 22mm, and are usually found on table lamps or GLS pendants.
– GX53 and GU10 bases
Low Voltage Lamps:
Low voltage lamp fixtures (sockets) will usually be connected to a transformer (or Driver) to reduce the mains voltage to 12V DC. Fortunately, you don’t need to touch the transformer when doing a lamp retrofit – quality 12V LED lamps are compatible with most halogen transformers making for a simple retrofit. The number of lamps that can be used on a transformer is dependent on the total wattage of the lamps, which should be less than that of the total wattage capacity of the transformer.
Lamps with the following bases run at low voltage, 12V DC:
– GU5.3 base: generally used by MR16 lamps
– GU4 base: generally used by MR11 lamps or capsules
– G53 base: generally used by AR111 lamps
Lamps and tubes are generally available in a variety of colour temperatures: the higher the colour temperature, the cooler the impression of the white light becomes. Daylight has a very high colour temperature (over 5,500K). LED lamps generally range from 2,700K to 4,200K. LED tubes generally range from 4,000K to 6,500K.
Colour temperature selection can depend on the kind of mood or atmosphere you prefer for your space:
- 2,700K = warm white (yellow white incandescent-like tone): suitable for residential or hospitality spaces where a more intimate feel is required
- 3,000K = neutral white (crisper white tones)
- 4,000K+ = cool white (bluer white tones)
- 6,500K = daylight: suitable for fluorescent tube replacement in utilitarian spaces
LED lamps are generally compromised of single or multiple light emitting diodes on a chip. The light is dispersed in a way that mimics conventional incandescent or halogen light sources using complex lenses. LED downlights (or spots) generally come with a variety of beam angle options to mimic the light dispersion from halogen reflectors. Selection of beam angle depends on application and ceiling height. Narrow beams tend to be employed for accent, product, or display lighting, or where ceilings are high and the beam has more room to disperse. Wide beams tend to be employed for general distributed room lighting, or where ceilings are low and the beam has less room to disperse.
Beam angles range from 15 degrees to 60 degrees, but options are lamp model dependant. Living spaces generally benefit from beam angles of 24 degrees and upwards.