When it comes to indoor lighting, using only wattage and spacing to plan your fixture layout isn’t always the best idea.
- Utilise Daylight
Natural lighting is an often under utilised part of energy efficient design which can provide zero-energy carbon-neutral lighting, with 100% colour rendering. Natural lighting should be considered in both the building plan, the layout of objects in the room, and the placement of light fixtures. Hundreds of years ago we designed our buildings to maximise the use of sunlight, and bit by bit we are again returning to this simple logic.
Top tip: Use operable windows with thick curtains and double glazing to ensure temperature control.
- Consider Purpose
Some areas (e.g. office desks) require a lot of light, while other areas (e.g. hallways) don’t need as much light, so don’t just aim for the same lux levels everywhere. In fact, using a balance between ‘dark’ areas and ‘bright’ areas is an important part of making an aesthetically pleasing lighting design, while also meaning you can get away with less lights in some areas.
Top tip: Use ‘task lighting’ for areas that require high illumination (e.g. reception desks).
- Balance Ceiling Height, Beam Angle, and Glare
Whereas older technologies (e.g. incandescent) shone light in all directions (360 degrees), LED lights have a more focused beam (usually < 120 degrees for an LED downlight). While its true that a 120 degree downlight can mean using less lights because the spread is wider, this can cause glare for someone on the other side of the room (less of an issue for higher ceilings, but then higher ceilings are more suited to narrow beam angles to ensure enough light reaches the surface below). Its a balancing act.
Top tip: Choose LED downlights which have a ‘baffle’ to reduce glare.
- Don’t Use Unnecessary Lights
There are many lighting installations which use lights in places they aren’t needed, often just for the sake of following a symmetrical spacing grid. Examples of this include lights placed too close to walls or columns, and lights in low traffic areas. Much of the time, adjusting your thinking and removing or re-positioning some fixtures can reduce the number of lights you need.
Top tip: Think ‘outside the grid’.
- Consider Room Reflectance Factors and Shadow
Another way to optimise your light sources is to choose paint and materials that have high reflectance. Using light coloured paints and finishes for your walls, ceilings, and even flooring will reflect more light and may reduce the number of fixtures you need. Dark colours on the other hand absorb more light and might lead to needing a higher number of fixtures to meet lux requirements. Another thing to consider is the placement of furniture which may cause shadows.