Become a leader in daylighting design with the VELUX Daylight Visualizer

Become a leader in daylighting design with the VELUX Daylight Visualizer

Daylight shapes the experience of a space like no other material and is fundamental to designing healthy and sustainable buildings. Good daylighting design can improve the health, mood, cognitive abilities, and productivity of occupants at home, school, or work while reducing building energy consumption.

Daylight Visualizer makes it easy to make informed decisions about architectural and daylighting strategies in your projects, and to assess compliance with daylight performance requirements in building regulations and building rating systems.

How to measure and evaluate daylight in buildings?

Illuminance and luminance

Daylight can be measured in terms of illuminance and luminance, two words that sound similar but should not be confused. Illuminance is the measure of the amount of light received on the surface and is usually expressed in lux (lm/m2). Luminance is the measurement of the amount of light reflected or emitted by a surface and is usually expressed in cd/m². The figures below show the illuminance and luminance renderings, with and without false colors applied, for an atrium space in a school project.

Daylight Visualizer illuminance rendering.  Image courtesy of VELUX Group
Daylight Visualizer illuminance rendering. Image courtesy of VELUX Group
Luminance rendering from Daylight Visualizer.  Image courtesy of VELUX Group
Luminance rendering from Daylight Visualizer. Image courtesy of VELUX Group

Illuminance simulations are used to assess the amount of daylight that will be available in interiors, as well as its distribution and uniformity in space, and it is usually calculated at worktop height. Luminance simulations are used to assess the risk of glare and visual discomfort, and they are typically calculated for a range of occupant positions and viewing directions in the room.

daylight factor

Daylight factor (DF) is an illuminance-based daylight availability metric that expresses the amount of daylight available inside a room (on a worktop) as a percentage. relative to the amount of unobstructed daylight available outdoors under overcast conditions, as shown in the figure below.

Daylight factor diagram.  Image courtesy of VELUX Group
Daylight factor diagram. Image courtesy of VELUX Group

The output of a daylight factor simulation is presented in a plan view with false color or iso-contour lines applied to show the corresponding daylight factor levels in space. It is common to assess the daylight performance of a space based on the achieved median daylight factor, which is a valid method to assess the requirements found in the European Standard for Daylight in Buildings EN 17037 and other building rating systems. The figure below shows a daylight factor simulation performed for an atrium space in a school project where a median daylight factor of 10.87% is achieved.

Daylight factor rendering from Daylight Visualizer.  Image courtesy of VELUX Group
Daylight factor rendering from Daylight Visualizer. Image courtesy of VELUX Group

Why are daylight simulation tools important?

Several factors affect the availability and quality of daylight in buildings, making simple rules of thumb, such as glazing to floor area ratio, inadequate for prescribing good daylighting. Climate, latitude, site context and building design all greatly influence the amount and distribution of daylight in interior spaces. Daylight simulation tools such as Daylight Visualizer are able to address this complexity and accurately predict a building’s daylighting performance prior to construction. The figure below shows how the daylight performance of a room with 10% floor glazing area changes depending on the window distribution, where the third situation achieves a median daylight factor 3 times higher than the first.

Impact of window placement on daylight performance.  Image courtesy of VELUX Group
Impact of window placement on daylight performance. Image courtesy of VELUX Group

Intuitive workflow and compatibility

Daylight Visualizer’s intuitive user interface makes it easy to create simple 3D models from scratch in minutes with the built-in modeler and lets you import existing projects from your favorite BIM/CAD software at any level details. Find various tutorials showing how to use the Daylight Visualizer on our VELUX BIM & Building Simulation Tools YouTube channel.

Daylight Visualizer's luminance rendering (left) compared to the built project photo (right).  Image courtesy of VELUX Group
Daylight Visualizer’s luminance rendering (left) compared to the built project photo (right). Image courtesy of VELUX Group

Download your free copy of Daylight Visualizer today and begin your journey to becoming a leader in daylighting design!

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