Lighting Planner

How it works

Light falling on a surface is measured in lux, which is lumen per square metre. The planner multiplies a widely used orientation value for each type of room by its floor area. Dark walls and floors swallow light, so for darker rooms it plans towards the upper end of the range, and for very high ceilings it adds a margin.

It then divides the total between the layers of light and suggests a colour temperature. The values are orientation values used in residential lighting design, not norms: trust your eyes, and fit dimmers wherever you can.

The rules of thumb behind it

• Living room: around 100 to 300 lux in general light, warm white 2700 K.
• Kitchen: around 300 lux in general light and about 500 lux on the worktop, 3000 to 4000 K.
• Reading and desk work: about 500 lux on the page.
• Colour rendering CRI 90 or more shows wood, stone, textiles and skin truthfully.
• Chandelier over a table: about half to two thirds of the table width, its lowest point 75 to 90 cm above the top.

All values are widely used rules of thumb from interior and lighting design, offered as guidance and never as norms.