thermal bridge calculations

Daylighting Calculations | View of the Sky | Daylight Factor

Daylighting calculations ensures that both your development and neighbouring properties will achieve enough natural daylight and view of the sky

Our daylighting calculations and 3d modeling will help you see clearly.

Natural Daylighting is an important part of any building and should be considered throughout the design process. Daylight provide light for work activities without the need for artificial lighting. Through the use of effective  building design, sunlight can help reduce the energy requirements of the building with reduced electric lighting and improved solar gains in the winter months. Daylighting Calculations are used to maximise natural light within the building.

daylighting calculations

What are Daylighting Calculations?

Daylighting calculation are used to establish three criteria. These are derived from Paul Littlefair publication Site Layout Planning for daylight and sunlight. Daylighting should be assessed in both dwellings and non-domestic buildings. Below is an outline of the three criteria.

Light from the Sky

There are several ways to assess the daylight entering any given room.There are three methods for calculation the light from the sky. These are detailed below:

Angle of Visible Sky

The angle of visible sky is a measure of the angle taken between the centre of the window in question and the top of the obstruction. A visible sky angle of over 65% will enable ample daylight into the room. (90% being completely unobstructed). An angle of less the 45% is unlikely to provide enough natural daylight.

Average Daylight Factor (ADF)

The average daylight factor is a measure of the overall amount of daylight  in a space.

The Code of Practice for Daylighting recommends and ADF of 5% for well lit spaces and 2% for a partly lit space. Anything below this will lead to a dark room or increase reliance on artificial lighting and increase energy use. A a minimum recommendation domestic kitchens should achieve and ADF of at least 2%, living rooms 1.5% and 1% for bedrooms.

The vertical sky component (VSC)

The vertical sky component (VSC) is the measured illumination on the outside of a vertical window as a percentage of illumination on an unobstructed roof plan, under overcast sky conditions. A VSC of at least 27% will provide reasonable room daylighting, while a VSC of 15% of less will make it difficult for enough natural light to reach the room.

AECB Building Knowledge
Passivhaus Trust