A few things to consider when choosing LED light bulbs
Manufacturer’s claims vary wildly about the efficiency of LED flood lights and can often be quite misleading. The simplest way to ensure that you are comparing “like with like” is to look at the efficiency in Lumens per Watt. That is, how much light do you get for each Watt of electricity used.
Today (early 2010), LEDs that are in production range in efficiency from about 20 to 60 Lumens per Watt. New developments should increase this to around 80 or 100 Lumens per Watt over the next few years. This compares with around 10-15 Lumens per Watt for old-fashioned incandescent lamps and 50-100 Lumens per Watt for fluorescent tubes.
Early LEDs were mostly a very much higher colour temperature (ie a bluish light) than the typical 2700K colour temperature of a warm white incandescent lamp. This has led many people to think that LEDs gave a “cold” light. LED technology has however advanced a great deal in the last couple of years and some types of LED are available in a range of colour temperatures from warm white (2700 or 3000K) up to daylight (6000K and beyond). LEDs with a higher colour temperature do however tend to be slightly more efficient than those with a lower colour temperature so some companies offer these as a way of making their products seem brighter. To replace standard incandescent or halogen lamps, a colour temperature of around 2700K to 3300K is preferred. Some companies use non-standard terms when describing the colour of LED street lighting such as “natural white” or “office white” which cannot be readily compared with other products. To ensure that you are comparing like with like always check the colour temperature.
The colour rendering of LEDs varies quite markedly between brands. For some applications this is not particularly important but for ambient lighting it is important to check the quality of light emitted. The LEDs that we offer for ambient lighting all have good colour rendering, comparable to that of a good quality fluorescent tube. Many manufacturers do not however quote a colour rendering index for their LEDs so we are rarely able to quote specific figures.
LEDs give off relatively little heat but do run reasonably warm and often incorporate a heat sink to dissipate any excess heat and maintain the wholesale LED tube light at optimum operating temperature. Compact lamps such as miniature spot lights can thus still get reasonably warm whereas larger bulbs and candles certainly cool enough to touch when operating.
The one area where LEDs really score highly is in their rated operating life which typically ranges from 20,000 to 50,000 hours. This is 20 to 50 times longer than a typical incandescent lamp so LEDs are ideal for use in areas where maintenance is difficult or long life is important.