Lighting calculation and designer lighting: what to know

  • Products

Lighting calculation is a procedure used to determine the amount of light needed in an environment, such as a room, in order to meet certain lighting requirements. It is based on the characteristics of light sources and objects to be illuminated to determine the appropriate number of lamps to be used. This practice is essential in arriving at optimal and comfortable lighting design for the activities performed in the room.

What is the purpose of the lighting calculation? The benefits

Lighting calculationis an essential procedure for designing an effective and efficient lighting systemin a room, improving the quality of life and the efficiency of the activities carried out within the room. This procedure makes it possible to achieve several important objectives for the optimal livability of a room, first and foremost determining how many and which lamps are needed to illuminate it in the best possible way.


Light that is neither too bright nor too soft allows for safe and comfortable movement in a room, minimizing the risk of falls or collisions.
Light at the right shade and intensity helps people concentrate and perform their tasks more carefully. In work areas, proper lighting can increase productivity and reduce eye fatigue, thus contributing to occupant well-being.


Lighting calculation determines the most optimal number and location of light sources so that lighting is uniform and free of unwanted shadows
A properly performed lighting calculation can help optimize the use of electricity, reducing waste and contributing to environmental sustainability.
It is also a versatile procedure that can be applied to the specifics of a given reality, whether domestic or commercial, to appropriately address the specific needs of the design and activities carried out in the environment.


The importance of lighting calculation in design lighting

Lighting calculation helps determine the exact position of light sources to highlight valuable objects such as statues, paintings, marble, and furniture elements, thus contributing to the aesthetics of the room.

This procedure makes it possible to influence the atmospheres of the home, to calibrate the intensity and color of light to suit the desired mood, such as warm and welcoming lighting in a restaurant or bright and dynamic lighting in a showroom.
Lighting calculation allows the intensity and color of light to be calibrated to suit the desired mood, such as implementing warm and welcoming lighting in a restaurant or bright and dynamic lighting in a showroom.
Lighting calculation plays a key role in optimizing design lighting, as it allows a balance between aesthetics and functionality to be achieved in the design of illuminated spaces.


This process allows direct and indirect lighting to be balanced. Direct light sources such as recessed LEDs can be used to illuminate focal points, while indirect lighting, such as through ceiling lamps, can help create a softer, more diffuse atmosphere in the room.
Lighting calculations should be made taking into account reflective surfaces in the room, such as floors and walls, in order to avoid annoying glare and reflections that could disturb vision or create visual discomfort.
A home lighting consultant takes into account the style of architecture so that the lighting blends harmoniously with the surroundings, raising the level of the overall design.

How to perform lighting calculation for a room

The lighting design calculation involves various elements such as utilization factor, maintenance factor and reflection coefficient. The technical standard of reference for lighting design is UNI EN 12464, which specifies lighting requirements for indoor workplaces. Here are some of the main calculations that are carried out as part of the lighting design calculation process.
Calculation of required lux: The first step is to determine how many lux (units of lighting) are needed in the room based on the specific needs of the activity in the room. For example, an office might require 500 lux of brightness, while a relaxation area only 200 lux.
Calculation of surface luminance:
this calculation is about assessing how much the surfaces in the room reflect light. Different surfaces, such as walls, ceiling, floor and furniture, have different degrees of reflectance. Calculating luminance helps determine how these surfaces affect the distribution of light in the room.
Calculation of light absorption factor:
this calculation considers how much the room absorbs light rather than reflecting it. Knowing the absorption coefficient of surfaces helps calculate the actual amount of light reaching the eyes of occupants.


Calculation of the mutual reflection factor: this calculation takes into account the surrounding surfaces that illuminate each other. For example, if walls are light, they may reflect light back to the ceiling and vice versa. This calculation helps prevent over- or under-illumination in certain areas of the room in question.
Calculation of luminous flux of sources: it is necessary to calculate the luminous flux (in lumens) produced by each light source used in the environment, and its interactions with surfaces. This value depends on the type of lamp or light source, its power and efficiency.
Calculation of the optimal positions of light sources:
using special lighting calculation software, the ideal positions for each light source are determined in order to achieve a uniform distribution of light in the environment.
As part of the lighting calculation, the type of lighting control to be used, such as switches, dimmers or intelligent lighting management systems, is taken into account. In addition, to carry out the calculation, the data sheets of the LED lamps that are going to be used are needed.


How to figure out how many lumens are needed for each room

Are you wondering how many lumens are needed to light a room to generate even and comfortable lighting?

The amount of lumens needed to light a room depends on several factors:

  • the color of the floor and wall materials
  • the arrangement and color of the furniture
  • the functions for which the room is intended
  • the size of the room
  • the number and type of light sources available and their angles
  • the type of lighting desired

The lighting calculation helps to tailor the distribution of lights to the specific needs of the activities. For example, a kitchen requires bright light above the work area, while in a relaxation area a softer, more welcoming light is preferable
Ideal lumen values tend to be:

  • kitchen between 300 and 400 lux
  • bedroom between 50 and 150 lux
  • hallways between 100 and 150 lux
  • work areas and studies between 300 and 400 lux

In any case, those listed above are rough values to be taken as indicative only.
The results of the lighting calculation are documented in a lighting plan that includes a lighting plan with specifications of the light sources, their locations, and installation instructions. This plan is then implemented to realize the desired lighting system.

Lighting calculation: why to rely on a professional

Lighting calculation is a technical process that combines the analysis of lighting needs, the choice of light sources and their optimal placement to create a well-lit and functional environment. It is an invaluable tool for interior designers, architects, and engineers, as it enables them to implement design lighting effectively and efficiently.

Lighting calculations can be performed on one's own only in the simplest cases. In all others, specific software such as Relux, Dialux and Litestar must be used.
It is advisable to always consult a home lighting professional to obtain assessments relevant to your case. In fact, a specialist can determine the appropriate number and type of light sources to set up uniform and elegant lighting.

Finally, the home lighting consultant performs a quality check to ensure that the lighting levels meet established requirements and that the environment is well lit and comfortable.

Do you need help performing lighting calculations appropriately to light your rooms appropriately? 9010novantadieci provides you with considerable experience in designer lighting for different types of homes.