High ceilings, big windows and good lighting (which can be dimmed) is a recipe that makes it hard to make bad space. High ceilings and big windows are easy to understand but lighting is complicated. Lighting is described in a number of ways: Lumens, colour temperature, colour rendering, angle… All of these have a strong impact on the mood of a space.
Colour temperature is a key mood effect with lighting and describes the colour of the lighting. In nature an ember in a fireplace would have a very low colour temperature and it would appear red – this would often be associated as a cosy type of light, daylight has a very high colour temperature and would be appear white, even blueish – again humans associate this with a freshness and daytime. A ‘warm’ colour temperature would be around 2500K and would be like a 50W incandescent bulb, a ‘cool’ white light might be around 5000K and would be like overcast daylight.
Lumens describes the light level falling on an object and is measured in candela. It is taking over from wattage as a description of a light – eg a 1750 lumen fitting as opposed to a 100W light. This makes sense now that LED’s and other types of light are available. It is also better to describe the light output rather than the energy input.
Colour rendering is the ability of a light to accurately represent the actual colour of an object. In some case a light with be strong enough to light an object but the object may appear weird; reds might not show up accurately while other colours seem fine – this is a problem with colour rendering.
Finally, for the purposes of this post, lights come with different beam angles. The wider the beam angle the less lumens falls on an object. This is true even if the power of the light fitting is the same.
So what type of lights? Well current regulations seek to achieve a power usage level of 5W per meter square or less (in Australia). This means that the lights will predominantly be LED’s. These are very efficient, long lasting lights. On the downside they sometimes contain fairly poisonous material – so getting rid of them is hard. They also don’t change colour temperature as the power changes. Old incandescent and halogen lights went from a very warm colour when dimmed to a bright colour when not dimmed. This is what we expect to happen with lighting and gives a natural effect that is pleasing. When LEDs are dimmed a blueish ‘bright’ light can be dimmed to make a blueish eerie light that is deppressing.
Because I feel dimmable lights are so important I use warm white LED’s of 2700K or less were possible. This allows them to be dimmed without looking too odd. In a couple of places I have used halogen lights so that I get a better quality atmosphere where it matters. These halogen lights occur as wall washers in some areas and as pendant lighting over the dining table. We also plan to use plenty of loose lamps to create variety.
With light layouts it is important to light areas for specific reasons. Sometimes lights are spread evenly over a ceiling to give a general room light level. This approach leads to a fairly dreary quality of space more suitable for an office (if its a dreary office). The lights for this project are specific to tasks or moods we seek to achieve. Two examples are the bathroom and the main living area.
In the bathroom we have halogen wall lights on either side of the mirror on one dimmable circuit and an LED pendant with a red glass surround that hangs over the bath and which would be behind a person facing a mirror on another dimmable circuit. There is also an LED downlight in the centre of the room, again on a dimmable circuit, as general lighting. This means that the pendant can provide soft backlight to anyone looking at a mirror (and remember vanity is insanity) while the mirror lights can give flattering lighting to the face – the centre downlight would be off. If someone is reading in a bath (me) then the pendant has a small opening at the bottom of the glass that allows a beam of uncoloured light out, the rest of the room would be red and fairly dark from the coloured glass.
In the living area we have narrow beam (24deg) 13W LEDs spaced evenly along the wall about 500mm from the wall. These act as wall washers lighting the walls only, these walls are white and will reflect ambient lighting into the room. Four LEDs on adjustable gimbles sit withing two recessed boxes near the centre of the room, they light up the centre of the room and will be adjusted to point at the sofa, two chairs and a coffee table. This room will also need a floor light or lamps on furniture to add variety, scale and nighttime cosiness.