Room surfaces bounce light around, so their reflectance affects how bright a space feels. These typical values feed the lumen method and coefficient-of-utilization calculations.
| Surface | Reflectance |
|---|---|
| White ceiling or paint | 80 to 90% |
| Light walls | 50 to 70% |
| Medium walls | 30 to 50% |
| Dark walls | 10 to 20% |
| Concrete floor | 20 to 40% |
| Dark carpet | 10 to 20% |
| Mirror | 90% and up |
Light surfaces stretch lumens. High-reflectance ceilings and walls recycle light and can raise effective levels by 20% or more, letting you use fewer or lower-output fixtures.
See the Fixture Spacing Guide and the Lux Formula.