Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications!

This is an AMP page - Open full page! for all features.

LENI - Lighting Energy Numeric Indicator

Sponsored Links

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.

Sponsored Links

Related Topics


Electrical engineering with units, amps and electrical wiring. Wire gauges, electrical formulas, motors and more.

Related Documents

Absorbed Solar Radiation

Solar radiation absorbed by various materials.

Electrical Equipment - Power Consumption

Typical power consumption and running time for common electrical equipment.

Heat Gain from Lights

Heat contributed by lights may have major impact on air-condition systems.

Heat Losses from Electrical Equipment

Heat loss from electrical equipment like switch-gear, transformers and variable frequency drives.

Illuminance - Recommended Light Levels

Working activities and light levels - required illuminance.

Lights vs. Power Installation

Lights vs. power installations in common types of buildings and rooms.

Luminous Efficacy

The visible light produced by light sources.

Materials - Light Reflecting Factors

Light reflecting factor materials.

Sponsored Links

Search Engineering ToolBox

  • the most efficient way to navigate the Engineering ToolBox!

SketchUp Extension - Online 3D modeling!

Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your Sketchup model with the Engineering ToolBox - SketchUp Extension - enabled for use with the amazing, fun and free SketchUp Make and SketchUp Pro . Add the Engineering ToolBox extension to your SketchUp from the Sketchup Extension Warehouse!


We don't collect information from our users. Only emails and answers are saved in our archive. Cookies are only used in the browser to improve user experience.

Some of our calculators and applications let you save application data to your local computer. These applications will - due to browser restrictions - send data between your browser and our server. We don't save this data.

Google use cookies for serving our ads and handling visitor statistics. Please read Google Privacy & Terms for more information about how you can control adserving and the information collected.

AddThis use cookies for handling links to social media. Please read AddThis Privacy for more information.