KelvinPlanHow much light each room needs, and what colour it should be.

Lighting a 18 × 28 ft home office

Total light needed
22,680lumens
504 ft² × 45 foot-candles
Room area504ft²
Target light levelIES guidance for a home office45foot-candles
Total lumens22,680lm
Colour temperatureneutral white keeps alertness up4000K
Bulbs (800 lm each)29bulbs
Recessed cans (4 ft spacing)709 lm each32fixtures
Room
home office
Width
18 ft
Length
28 ft

Where 22,680 lumens comes from

Lighting is specified in foot-candles — lumens landing on each square foot of the surface you care about. A home office is worked to 45 foot-candles. Across 504 ft² that is 22,680 lumens in total.

Split it up

One fixture putting out 22,680 lumens and 32 fixtures adding up to the same number light a room very differently. A single source throws hard shadows and glare; several spread the light and make the room feel larger. Aim for layers — ambient, task, and something low for the evening.

Colour temperature

4000K suits this room. Warmer light reads as relaxed and is what you want where people wind down; cooler light keeps edges and colours crisp, which matters where there is work to do.

Notes

  • Foot-candles are lumens per square foot at the work surface. Ceilings above 9 ft, dark walls or dark flooring all eat light — add roughly 10% per extra foot of ceiling height.
  • Spread the total across several fixtures rather than one bright source. One 22,680 lm fixture and 32 smaller ones add up the same but look completely different.

Nearby sizes