Articles and whitepapers

Lighting Technology - Design Considerations (1/2/2007)

By Melanie Shaw, Brilliant Lighting and Brilliant Living

As residential architecture has changed, so must lighting design. Large multifunctional living areas, double- or triple-height spaces, architecture with curves and angles, substantial glazed areas of walls or ceilings and increasing energy efficiency awareness and legislation are all posing new challenges and opportunities for lighting. With greater consumer awareness of the benefits of interesting lighting, and 'mood' lighting becoming a 'must have', the day of the grid of downlights is thankfully over! But what to do instead?

Balancing the client's needs

In designing schemes for the high-end residential market, we are balancing three key areas: the opportunities and constraints thrown up by the architecture; the clients' desired functionality and 'look and feel'; and budget. Understanding these three elements is critical. We will generally spend hours asking questions and kicking around ideas. Clients can get very surprised when they've just got planning permission and we ask them about what the focal point in the room will be, what their plans are for curtains, and whether the bath will be freestanding or not, but this sort of level of detail is necessary to really make the most of the lighting scheme.

All three elements impact on the lamp types chosen, which in turn drives the look of the fitting. In an ideal world, there would be a wide range of lamp types and fittings which combine the energy efficiency of fluorescent, the size and maintenance requirements of LEDs, the dimming, colour temperature and colour rendering of halogen, and cost not very much. Despite ongoing innovation in all these areas, the technology is not yet there, so it is a question of prioritising the relative needs.

A dynamically-lit kitchen illustrating the use of different lighting layers and lamp technologies

Lighting mixes

In the kitchen illustrated above, the predominant light source had to be halogen to bring out the colour of the limestone floor and oak furniture. We used adjustable MR16 downlights around the perimeter to wash the walls and units, but AR70 fittings over the island to provide a punch of light without glare in the relatively low ceiling. The central AR70 lamp has an 8 degree beam and is on an individual circuit so that flowers can provide a striking centre piece even when other lights are dimmed. Fittings were carefully positioned only to light what was required rather than providing blanket coverage. The key to bringing the kitchen alive though, was in getting sufficient light onto the ceiling to 'heighten' it, and in providing interesting accent lighting. This was achieved by using warm white LEDs to uplight the window bay and to wash across the floor and the steps, and by using a miniature xenon Lightgraphix Light Tube to uplight the lantern of the conservatory.

The LEDs and a minimal amount of under-cabinet fluorescent lighting (not shown) provide an energy-efficient route to providing some light in the kitchen for when people are just popping in and out in the evening. A Rako lighting control system enables the client to set the different scenes at the touch of a button, and the wireless nature of this system was easily able to cope with the number of kitchen design changes that occurred during the build.

The same kitchen looking back towards the orangery - in the 'cooking' mood and in the 'entertaining' mood

Xenon provides a very warm dimmable light, perfect for bathing, and has a 20,000-hour lamp life - useful when you have to fish behind the shadow gap to change the lamp. Unlike fluorescent, it easily bends around corners and is cheaper and warmer in colour than LED.

A flexible xenon fitting accentuates the curve of the wall, and provides a dimmable golden light

Heat considerations

Another design factor we often have to consider is heat. With open ceilings and substantial glazed areas, floor recessed fittings are increasingly important as a light source as well for highlighting architectural features. 'Standard' halogen ground-recessed uplights have extremely high surface temperatures, and LED fittings which could produce the required light output are well beyond most people's budgets. Several manufacturers such as Louis Poulsen, Lightgraphix and Cube have developed relatively low-heat halogen fittings by locating the lamp lower down in the housing to reduce top plate temperatures. Even when using these fittings, we try to create as large a void space as possible in order to increase ventilation and reduce heat further.

Pendants

High open ceilings are a fantastic opportunity to feature stunning modern pendants. As well as supplying major brands we also seek out small British designers who are doing some wonderfully innovative things with porcelain, glass and other materials. As impactful as they are, pendants should almost always be used in conjunction with a variety of other light 'layers' in order to provide depth and wider interest. Where applicable we recommend putting pendants on winches to facilitate maintenance and cleaning.

A selection of striking pendants on view at Brilliant Lighting's double height premises

Energy efficiency

Energy efficiency is becoming increasingly important, even in high end homes. Many low-voltage halogen fittings can be substantially more efficient through the use of Osram IRC or Philips Masterline energy saving lamps. Osram for example, claims up to 68% cost savings on some lamps.

While fluorescent generally has a negative image of flickering, buzzing and bad colour, clients are very surprised at the effects we can achieve with this technology. For example, back-lighting the top and bottom of large mirrors using dimmable T5 fluorescents to create a very clean-lined effect both washes light down on to the basin and provides a diffuse ambient light at the top, as well as looking almost like moon-light when dimmed. It also creates fantastic make-up lighting when combined with halogen 'starlights' mounted on the surface of the mirror.

LEDs are developing at a rapid rate, but with colour temperature, colour rendering and output as they are now, we only use them where their size, maintenance or colour change characteristics make them the best solution.

Using LEDs to uplight orchids

Good-quality LEDs are also expensive, and we would steer clear of cheaper ones due to issues of life expectancy, colour binning (if not done rigorously enough no three 'whites' are the same white), and output.

Lighting control

Lighting control technology comes into its own when used in conjunction with good lighting design. It in itself, it will not provide mood lighting, but it is a fantastic facilitator. When designing a scheme, we think through exactly what one wants to look at or not look at for each of the different uses of the space, and this informs both the overall design and the circuits required.

Using a conventional wiring system, many rooms would end up with banks of rotary dimmers which the client would never be bothered to adjust. Furthermore, these nearly always tend to be located at the wrong door when you enter a space with multiple routes in! A control system overcomes all of these issues and facilitates wider 'whole house' intelligence, such as the ability to track and replay real light patterns and curtain movements for additional security whilst away, having some circuits come on automatically at dusk, or allowing 'one touch' control of lights, blinds, projector, screen etc in a home cinema environment.

From an energy saving perspective, a control system encourages people to use only the light levels that they need at that time and, through 'whole house off' functionality, prevents lights being left on inadvertently. In addition, dimming halogen lamps by 5% is unnoticeable to the user, but substantially prolongs lamp life, so we take this in to account when we program scenes.

Conclusion

Interesting and appropriate lighting design together with a lighting control system is probably one of the biggest single 'wow' factors a client can install in a house.

Example of the right fitting in the right place

People are increasingly realising that without good lighting, their investment in expensive fittings and interior décor can be wasted. Clients who are on their second house build and who have realised how difficult it is, are particularly keen on getting it right this time around! The key is to start thinking about the lighting very early on in the build. You need to understand where you want your eye to go and therefore what you light at any particular time of the day, put in sufficient circuits to facilitate this, and choose the lamp technology which best suits the various trade-offs.

Melanie Shaw is a Partner in Brilliant Lighting and Brilliant Living. Brilliant is an independent lighting design consultancy and smart home custom installer.

www.brilliantliving.co.uk