Comment, Lighting Controls

More efficient luminaires won’t save the planet by themselves. We need to try a bit harder

We need to harness daylight properly if we're to make lighting truly sustainable, says Lance Stewart

Lux Review columnist Lance Stewart shares his experience  on how lighting can help you do your bit to tackle climate change.

In 2006, the Stern Review spelt out the dire consequences if we fail to act on global climate change. Some people still don’t buy it, to which Stern replied: ‘Those who say that climate change doesn’t exist are being understood as the flat-earthers that they are.’ (For those who missed the update from Pythagoras, circa 520 BC, the earth is not flat.)

UN president Ban Ki-moon added: ‘The clear and present danger of climate change means we cannot burn our way to prosperity… We need a clean industrial revolution.’

So where does light come in? Well there’s no doubt that the power used for lighting is farting out megatons of greenhouse gases despite increasing efficiency of luminaires: the International Energy Agency reckons that globally, lighting is using about 18 per cent of all the world’s electricity. What, us?

Okay, so how can we mere lighting people do our bit to help save the planet in this Year of Light? I’ve changed my company, Creative Lighting, from a power gobbler to a green energy producer, and these are the top six lessons I learned in the process.

1.         Punch holes in the roof

If the building is single story, let the sunshine in. We installed 16 skylights then did months of thermal tests inside and out: the good news is that heat gain for the latest Solatube skylights is precisely bugger all and UV is also almost non-existent (that’s four months of my life I won’t get back). They are even 600mm square for standard T bar ceiling installs. The bad news is that shoddy installers can make your roof leak, repeatedly. Proper flashing and a good installer are essential or you’re going to need more buckets.

You should also consider shades – we fitted Dali control boards to our shades to integrate them with our lighting controls. When you have up to 2,000 lx in your boardroom and you want to videoconference, dimming the sunshine is a must.

A fun side benefit of good commercial skylights (that look deceptively like luminaires) happens when a lighting designer whips out a light meter, wonders aloud why you chose 6000K and such a high lux level, then becomes totally confused by a reading of 99+ CRI.

And if you still have room on your roof after your skylights have turned it into Swiss cheese, install photovoltaic panels on every spare inch of it. We installed a 5kW Bosch solar array and are producing eight times the energy needed for lighting and control and twice as much power as the entire company uses for everything, even heating, ventilation and air conditioning.

2.         Shorten the timeouts

This one is for every lighting control company, not just ours. If you want to annoy people, turning the lights off while they are still using the room is a no-brainer. But leaving the lights on long after people have gone just adds to our climate change woes. Somewhere in between is the happy medium, with different times for different spaces.

We found that a four-second fade with a maximum of 90 seconds total was more than long enough in our toilets and stores for example (a one-minute timeout from last occupancy detection to a warning level that holds for up to 26 seconds of absence). Contrast a minute and a half with your typical timeouts of 15 minutes or longer, and we’re talking about serious energy savings. All you need are reliable sensors and any decent intelligent lighting control system (which also happens to give you the added benefits of dimming and scene control for lots of different lighting states).

3.         Chuck out the lights

Retrofit energy-saving light sources come in all varieties. Most aren’t ideal for the luminaire you put them in. Ditch the old lights instead and put in new ones that are designed around the energy-saving light source (that’s probably LED) for best luminous efficacies. I did and it paid off.

4.         Min the max, baby

A good lighting design works with the space, its furnishings and its occupants, not just in it. That means that compared with God-awful grid pattern lighting, getting the right lights in the right place for the right tasks will result in more luminaires and illuminance than strictly required by some arbitrary building code. So dim back any excess light.

If the lights are Dali, that’s easy – simply reduce each light’s maximum level. You can always increase the max sometime down the track, when lumen depreciation kicks in. We have some 26W LED downlights with a max set as low as 22 per cent and yes, we have accurate energy monitoring too, so we can be sure that proper dimming does reduce the power consumption proportionately.

5.         Make the switch

A lot of lighting control systems in commercial projects are there, let’s face it, largely because lazy bastards can’t be bothered turning the lights off when they leave the room. But not everyone is so lazy, and I’m willing to bet that more people will be wanting to turn the lights off themselves as the planet’s thermostat, and their power bills, keep going up. So make it easy for them: install an obvious switch (or the touchscreen equivalent if you prefer) with a delayed exit so the lights fade down slowly enough to let them out without barking their shins in the dark.

Program the switch to have an intelligent toggle so that, if it’s a single switch, it will toggle the lights off when the lights are on and vice versa. And temporarily disable that room’s sensors so the lights fade down to off and they have time to exit. Simple.

6.         Harvest daylight

Daylight harvesting makes sense but has often been one of the most difficult things to do well, raising questions about net benefits. Because we installed skylights that pump out bucketloads of free light (and rain too, until we got the roof flashing right), we worked out a way to use Tridonic’s Dali sensors with our Control Freak controls that made daylight harvesting quick, easy to set up and very effective. Simply use two of the room’s switches to program the light level to be maintained. All you need is a lux meter, two fingers and a couple of minutes to set it up.

So, there you have it: half a dozen easy lighting strategies to help save the planet; your grandkids will be better off and your clients will save power and money. Or do nothing and the world goes to hell in a handbasket. Simple, really.