25 per cent of an organisation’s electricity costs come from lighting

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You’ve been tasked with upgrading the office lighting, and you are probably looking at two choices: keep the existing fittings and replace the lamps with more energy-efficient alternatives, or re-design the scheme to include a newer technology.

This ‘newer technology’ is likely to be LED. The industry has reached a tipping point inasmuch as being able to offer accessible LED solutions that also provide a quality of light required for a comfortable working environment.

Offices have been traditionally lit with 600 x 600 Linear Fluorescent luminaires (LFIs), and compact fluorescent downlights.

The most efficient way to upgrade a system’s lamps is to adapt the maintenance programme specification. Historically, most commercial offices have worked to a three-year maintenance cycle and so the easiest route to cost savings is to specify a ‘better’ alternative when the next cycle is due.

If an office is still utilising LFLs, a switch to energy efficient alternatives will achieve an 8-10 per cent reduction in energy use. With a minimal increase in cost per lamp, the payback is just a matter of months.

For CFL downlights, the savings to be made are more subtle, yet still significant. In this case, it’s how long the lamps last that can really make a difference. By switching the specification, maintenance cycles can be extended, bringing an organisation real cost savings on re-lamping.

For those that do have the desire to upgrade to LEDs, take time to evaluate before committing to a specification, as there’s a number of key things to consider.

First, when comparing costs, make sure you are comparing like-for-like products. Let’s take a case in point. The emergence of LED alternatives to traditional LFL is arguably one of the most exciting developments in office lighting in recent times. In this arena, initial capital investment can be a barrier, so understandably organisations are seeking the cheapest deals in order to make those pay-back calculations work. However, the risks involved shouldn’t be underestimated.

Differences in colour consistency and lumens-per-watt each play their part in the overall effectiveness of a lighting solution. In fact, the difference in the lm/W output of apparently equivalent LED panels can mean that up to twice as many of the cheaper fixtures can be required to light the same space. This increases direct and indirect energy usage through an increase in heat load.

When setting a spec, consider the office layout. Open plan offices are generally configured
so that lighting is spaced at 2.4 metre centres, but LEDs offer a new perspective.

For example, the better distribution of light possible from some LED luminaires means that these fixtures can be positioned at  metre centres, so that once again, fewer fixtures are required. This the importance is in understanding the light output achievable, so that a job isn’t over-specified – and therefore over-priced.

Conversely, there are new LED fixtures due on the market, specifically designed for cellular offices that will only accommodate 2.4 metre centres.

Ssavings can be made on downlighters by replacing CFL with LED modules. A 13W product to replace a 26W CFL, for example, could achieve a 50 per cent energy reduction – and payback in less than two years.

More significantly, this type of module is upgradeable; LED module can be removed and upgraded as technology develops, meaning  that any investment in the lighting fixtures is future-proofed from obsolescence.

However, the most crucial element of any specification is reliability, and that’s not just in terms of lumen performance. Studies into the physiological and psychological effects of lighting demonstrate that it can affect productivity and mood – and eyestrain has been cited as a leading cause of physical stress in the workplace. A gradual degradation in light quality will also have an adverse effect on the working environment. Colour shifting, for example will not only ruin the overall aesthetic of a space, but may also effect the well-being of the working environment.

The fact is that not all LEDs,  and therefore LED products, are the same. In recent years, the market has become flooded with products claiming to replace conventional lamps and luminaires.
When choosing a manufacturer, ask for proof of their claims. There are approved methods for measuring lumen depreciation of LED light sources (LM80) and electrical and photometric measurements of solid-state lighting (LM79). In addition, look for systems with performance claims based on testing, ideally at LED, sub-system and full-system level.

The benefits of investing in energy efficient lighting are clear. Whether you take a progressive approach to upgrading or jump straight into LED, the key to achieving the best ROI is to understand the capabilities of the light source chosen, in terms of lumen performance, light distribution, and light quality.

Finally, challenge a suppliers’ claims – if it’s competent, it won’t shy away from providing evidence to support them.

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