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LENI - Lighting Energy Numeric Indicator

Energy consumption of lighting systems

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The LENI - Lighting Energy Numeric Indicator - stands for the actual energy consumption of a lighting system in kWh per square metre and year - and can be calculated as

LENI = Σ(Pn fc) ((td fo fd) + (tn fo)) / A                          (1)


LENI = lighting energy numeric indicator (kWh/(m2 year))

Pn = installed load (kW)

fc = reducing factor due to use of daylight control (<1)

td = annual hours of use by day (h) 

fo = reducing factor due to use of present based control (<1)

fd = reducing factor due to use of constant lighting maintenance control (<1)

tn = annual hours of use by night (h) 

A = area (m2)        

LENI is according to EN 15193 Energy performance of buildings – Energy requirements for lighting.

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