Here we will prepare you with the right questions to ask and provide a rough guide to estimating downlight spacings for a house, however we urge you to not rely upon such shortcuts and allow this very question to lead you deeper into learning how to really use recessed LED downlights and lighting in your space.
The recessed downlight is such an incredibly useful and versatile lighting tool that you are going to want to use them in your own project, and a key consideration is just how apart do they need to be from each other in the ceiling?
However, the downlight’s strength of being so effective, discrete and easy to install can also be its weakness as they are over relied upon, used incorrectly and potentially can spoil your lighting scheme. There is way more to learning about their spacing’s than just distance.
How to Use Recessed Downlights will show you how to achieve the right layout of recessed downlights for your project.
When you purchase almost anything the supplier would usually give you instructions on how to use it. Interestingly lighting manufacturers do not, as there are too many variables to consider to accurately advise properly. So we must advance with caution in the knowledge that these calculations are a crude guide and rely on downlights only to achieve a blanket covering of light and do not consider other circuits of light.
You will need to know these answers to begin:
Now follow this simple step by step process to how many downlights are required:
Multiply the room width by its length.
Eg. A dining room is 14ft (4.3m) x 13 ft (4m) = 182 square feet.
Using LED light sources multiply the area by 0.3
Eg. The dining room is 182 x 0.3 = approx 55W
If you are not using LED lamps multiply the area by 1.5
Eg. The dining room is 182 x 1.5 = 273 watts
See what the wattage of the downlight is or it’s LED lamp
Efficiencies vary but a 11W LED downlight it is approx the old output of a 50W lamp
Divide total wattage required by the chosen downlight wattage
Eg. 55W divided by 11W = 5 qty
An approximation by wattage really is a rough guide to show you how to get a very good general illumination without any other source. Now we can decide upon how far apart the downlights will need to be for the room.
The shape of the room will guide your choices in the knowledge that most downlights have a ceiling footprint of 1m-1.2m diameter in a ceiling height of 2.4m-3m (8ft-10ft).
For an even illumination in the room this means that downlights should be approx 1m to 1.2m (3ft-4ft) apart and no closer than 600mm (2ft) to the wall.
We do not recommend positioning downlights in grids and even spacings unless the space under them requires a uniform illumination. Eg. a work room, laundry utility room, some parts of a kitchen.
As a guide for residential downlight spacings with no more than 10 ft ceiling heights, divide the ceiling height by 2 to give you the rough space between fittings.
Eg, 8ft ceiling would be 4ft spacings between downlights.
Note: Rooms over 10ft (3m) high this estimation process would increase the distance between downlights which works for the spread of light when it reaches the floor but the output would have to increase to compensate as the light is weaker on lit surfaces the further it has to travel.
For open plan rooms divide the ceiling spaces by how each area will be used. Apply the estimation process as above for each area’s general ambient illumination and apply the following compensation according to these specific uses.
Task lighting requires a more focused intense illumination such as a kitchen work surface. If the downlights are directly over the work surface the shorter distance between downlight and counter top will mean the light is more intense. Keep the spacings the same. If the downlights are not directly over the task activity then you may find reducing the spacings of adjacent downlights to 32” (800mm) and make sure the beam width covers the surface to help concentrate the light
Lounge areas requiring low level ambient levels of light either use a dimmer to adjust the output or widen the distance between fixtures to 5ft-6ft (1.5m-1.8m) and therefore use less.
The recess space behind a downlight is important too. Make sure a LED downlight is not covered by insulation behind the ceiling unless the manufacturer has designed for it to do so. An unofficial guide is to allow a 6” space apart from the insulation for each downlight (150mm x 150mm). Please refer to the manufacturers installation instructions.
The room space the downlight is in is also important. Wet areas indoors and outdoors require a downlight to be IP rated to at least IP44 and above in Europe.
Recommended: The Best LED Downlights: Buying Guide & Reviews