LED lights trial

LEDs offer many advantages, including a very long life span, improved efficiency and immediate full brightness when switched on. According to CarbonetiX Founder Bruce Rowse, “To date, high costs, exaggerated performance claims and uncertainty about light depreciation have held LEDs back from becoming a viable replacement for the familiar fluoro tube.”

CarbonetiX, with the support of the Victorian Government Sustainability Fund (managed by Sustainability Victoria), and the City of Frankston, conducted a trial to test the viability of using LED lighting as a fluorescent substitute. It also researched trends that are likely to result in the widespread uptake of LEDs by 2015.

The trial revealed three main barriers to using LED lights today and the trends that will overcome them:

1. High costs - LED tubes purchased for the trial ranged in price from $50 to $120 per tube - with the best performing tube at the higher end. This is expensive compared to $5 for a good fluorescent tube. “But,” Rowse says “according to industry sources, prices are on a downward trend, and by 2015, an LED tube should set you back just $20 to $30 per tube.”

Installation costs also need to be considered, but if you choose one designed for retrofit, the cost is no more than that of replacing a failed fluorescent tube with a new one.

2. Uncertainty about lumen depreciation and lamp life - Lumen depreciation is the loss of light that occurs from a lamp as it ages. For example, a fluorescent tube will typically produce 15 to 20% less light at the end of its life.

LED manufacturers are claiming lamp lives in the order of 50,000 to 100,000 hours. However, the technology is developing so quickly that it is impossible for a manufacturer to test a lamp for this long before it is obsolete. A new testing standard now means lumen depreciation can be estimated to 36,000 hours.

As more manufacturers test to this standard, buyers will have greater certainty about the longer-term performance of their investment.

3. Exaggerated performance claims - None of the six lamps tested in the trial produced the amount of light their manufacturers claimed. The best-performing lamp in the trial produced less than 80% of light the manufacturer claimed.

Fortunately, there is a move towards certification. The development of standards gives confidence that LED tubes as a fluorescent substitute will eventually be subject to a standard, such as Energy Star.

Notwithstanding exaggerated performance claims, lamp luminous efficacy is improving. Efficacy is a measure of the amount of light produced per watt of electricity consumed. New fluorescent lighting typically has an efficacy of 80 to 100 lumens per watt.

“Our experience in testing LEDs over the last two years has shown a great improvement in LED efficacy over that time,” says Rowse. “At current rates of improvement, it is reasonable to assume that an efficacy of 150 lumens per watt will be achieved before 2015, and that lamps will then be commonly available with an overall efficacy of at least 120 lumens per watt. This would mean that an 18 or 20 W LED could be confidently used to substitute a 36 W fluorescent with no loss of light output.”

What can be done in the meantime?

According to Carbonetix, while waiting for LED technology to improve, building owners and managers should explore other options to reduce their fluorescent lighting energy use that have a fast payback and will provide both financial and environmental savings.

Wastage can be reduced and large energy savings can be achieved by reducing the number of tubes in the building by:

• upgrading to high-performance T8 tubes of 100 lumens/W 
• fitting mirror-like reflectors in the light fittings to reflect light going upwards, sideways and downwards and thus make it useful 
• refitting opaque diffusers with prismatic diffusers if appropriate 
• then undertaking an illumination assessment using a lux meter and delamping so that the space is not over-illuminated

According to Rowse, “Building owners will save money and greenhouse gas emissions by installing these technologies now, as well as generating a positive return on investment. Then in around 2015, they are likely to be able to save even more by upgrading to LEDs.”