Lighting education articles
Education pages that support a calculator or table decision: unit language, lumen allowances, retrofit arithmetic, colour rendering and glare.
Lighting basics
Lux, lumens and room lumen allowances before a task plane, surface or fitting-count estimate is prepared.
Retrofit and energy
Replacement output, connected load, annual energy and payback context kept separate from fitting selection and wiring scope.
Light quality
Colour rendering, UGR, surface appearance and visual comfort language for calculator, table and guide records.