25 November 2014

Amongst the rapidly expanding range of LED lighting products on the market we have recently seen the emergence of lamps that offer an enhanced range of lighting and other services (such as wireless operation, colour adjustment, and internet connectivity). While these developments may provide exciting and useful additional services to the consumer, there is emerging evidence that the trend may also work against the current strive for increasing lighting efficacy levels. In many cases additional energy may be used (or the lighting performance of the product reduce) without consumers being aware.

We have recently tested the performance, including measuring standby power consumption, of two wireless operation LED lamp products available in the Australian market. One of these lamps (Lamp A) had standby power of about half a Watt while the second (Lamp B) consumed about 3 Watts in standby mode. Considering Australian houses have on average approximately 48 lamps in-situ, the transitioning to these LED lamps with wireless capability by even a portion of this lamp stock means that the collective standby power consumption will have real implications for household energy consumption and in some cases could reverse energy savings gained from moving to LED lighting.

The Figures 1 and 2 present power consumption, including standby mode, for the two lamps tested when they are turned ON for one hour every day throughout the year. Taking into account standby power use, in this scenario Lamp B actually uses more power than an equivalent inefficient tungsten filament incandescent lamp (now phased out) would use when turned ON for the one hour each day. Including standby power, both wireless models consumed far more energy than the LED efficacy levels recommended by the International Energy Agency (IEA) 4E Solid State Lighting (SSL) Annex and used more energy during the standby period than during the hour of operation.

Missing media.

Figure 1: Power consumption, including standby mode, of the two LED lamps with the equivalent incandescent lamp energy and IEA LED recommended energy consumption shown.

Missing media.

Figure 2. Standby versus lamp ON power consumption of the tested lamps.

 The longer the daily use of a lamp, the less significant the standby mode power consumption is relative to the power consumed when ON, however the average residential time of use (i.e. when turned ON) for lamps in Australia is only between 1–2 hours.

 The Figure 3 compares the measured efficacy (lumens per Watt) of the tested lamps to similar incandescent lamps and the IEA 4ESSL recommended LED efficacy levels.

Missing media.

Figure 3. The measured efficacy of the tested lamps compared to an equivalent incandescent lamp and the IEA recommended LED efficacy levels.

 Other new developments have seen lamps emerging that increase power use over time to maintain constant lumen output, or vary lumen output in order to reduce the impacts of overheating. While addressing technical challenges with LED lighting, these approaches also make it more challenging to test the performance of these lamps, and for consumers to understand the service and associated energy consumption being provided.

 The Australian government is working with a number of other countries that have also been testing wireless LED lamps with standby power modes and this issue is currently being investigated further by the IEA 4E SSL Annex of which Australia is a member. It will also be discussed in the upcoming Australian / New Zealand LED product profile.