EN 15193: Energy performance of buildings — Energy requirements for lighting

Luminaire parasitic power (PPi)

Electrical power from the mains supply consumed by the charging circuit of emergency lighting luminaires and the standby power for automatic controls in the luminaire when lamps are not operating, measured in watts: 

P_pi = P_ci + P_ei [W] 

Luminaire parasitic energy consumption (WP,t)

Parasitic energy consumed in period t, by the charging circuit of emergency lighting and by the standby control system controlling the luminaires, measured in kWh. 

Parasitic power of the controls only during the time with the lamps off (Pci)

Parasitic input power to the control system in the luminaire during the period with lamps not operating, measured in watts. 

Emergency lighting charging power (Pei)

Input power to the charging circuit of emergency luminaires, measured in watts. 

Total installed parasitic power of the controls in the room or zone (Ppc)

Input power of all control systems in luminaires in the room or zone, measured in watts: 

Total installed charging power of the emergency lighting luminaires in the room or zone (Pem)

Input charging power of all emergency lighting luminaires in the room or zone, measured in watts: 

Total energy used for lighting (Wt)

Energy consumed in period t, by the luminaires when operating, and parasitic loads when the

luminaires are not operating, in a room or zone, measured in kWh. 

Energy consumption used for illumination (WL,t)

Energy consumed in period t, by the luminaires to fulfill the illumination function and purpose in the

building, measured in kWh. 

Luminaire parasitic energy consumption (WP,t)

Parasitic energy consumed in period t, by the charging circuit of emergency lighting and by the

standby control system controlling the luminaires, measured in kWh. 

Annual operating time (to)

Annual number of operating hours of the lamp(s) and luminaires with the lamps on: 

to = t_D + t_N [h] 

Standard year time (ty)

Time taken for one standard year to pass, taken as 8 760 h. 

Daylight time usage (tD)

Operating hours during the daylight time, measured in hours. 

Non-daylight time usage (tN)

Operating hours during the non-daylight time, measured in hours. 

Emergency lighting charge time (te)

Operating hours during which the emergency lighting batteries are being charged in hours. 

Scene setting operation time (ts)

Operating hours of the scene setting controls in hours. 

Useful area (A)

Floor area inside the outer walls excluding non-habitable cellars and un-illuminated spaces, measured

in m². 

Daylight dependency factor (FD)

Factor relating the usage of the total installed lighting power to daylight availability in the room or zone. 

Occupancy dependency factor (FO)

Factor relating the usage of the total installed lighting power to occupancy period in the room or zone. 

Absence factor (FA)

Factor relating to the period of absence of occupants. 

Constant illuminance factor (FC)

Factor relating to the usage of the total installed power when constant illuminance control is in

operation in the room or zone. 

Maintenance Factor (MF)

The ratio of the average illuminance on the working plane after a certain period of use of a lighting

installation to the initial average illuminance obtained under the same conditions for the installation. 

Lighting Energy Numeric Indicator (LENI)

The lighting energy numeric indicator (LENI) is a numeric indicator of the total annual lighting energy

required in the building. 

Lighting Energy Numeric Indicator for the building

 LENI = W/A [kWh / (m² × year)]

 where

 W is the total annual energy used for lighting [kWh/year]

A is the total useful floor area of the building [m²]