LET THE DAYLIGHT IN

Levels of daylight provision by openings in vertical and inclined surfaces according to the EN 17037 EU standard.

• The daylight performance of the interiors affects the value of the entire building. Real estate professionals can use this benchmark to compare properties and deliver more accurate return on investment forecasts.
• Daylight provision metrics help architects and their clients evaluate design alternatives during building design. The future building's daylight performance can be used to estimate the annual energy usage of electric lighting.
• ​For daylight design, the location and surroundings of the building, the size, position, glazing, and orientation of the openings, and the properties of the interior (furnishing, wall, and ceiling surface reflectance) must be considered.
• To achieve a certain level (minimum, medium, or high) of the EU standard, a target illuminance level ET (lx) must be achieved across a fraction (F plane, %) of the reference plane for at least half of the daylight hours (F time, %). In addition, a minimum target illuminance level ETM (lx) must also be achieved across the reference plane.

Levels for daily sunlight exposure by the EN 17037 EU standard.

• During building design - sunlight access must be handled in conjunction with solar gain evaluations, the use of passive solar systems, as well as visual comfort requirements by architects.
• Design considerations will influence the form and functional layout of the building itself, the design of the façade, the size and orientation of the daylight openings, and the characteristics of the shading systems.
• Minimum exposure to sunlight should be provided in common areas of kinder gardens, retirement homes, patient rooms of hospitals, and at least one habitable room of residential dwellings or houses.
• The duration of direct sunlight throughout the year in an existing building interior can be determined with on-site measurements, using photographs and sun-path diagrams.
• The level (minimum, medium, high) of exposure to sunlight is evaluated through the expression of the minimum number of hours during which a space receives direct sunlight, for a clear, cloudless reference day in the year between February 1st and March 21st.

Levels of threshold for glare protection by the EN 17037 EU standard.

• Daylight has a significant impact on visibility, visual comfort, aesthetics, task performance, safety, mood, satisfaction, work productivity, and social interactions. The presence of direct sunlight or its reflection in the field of view, however, can cause a risk of glare in workspaces.
• Sunlight—particularly in classrooms and workspaces—can cause serious visual discomfort. Once the sources of glare and their duration are identified, the probability of glare can be minimized.
• A glare assessment is suggested in spaces where activities are comparable to reading, writing, or using display devices, and the occupants are not able to choose their position and viewing direction. For glare protection, retractable shading devices with variable translucency are recommended.
• The Daylight Glare Probability (DGP) approach is used to assess protection from glare caused by daylight. This considers both the illuminance at eye level and individual glare sources of high luminance to estimate the fraction of dissatisfied persons. 

Levels of view out from a given position according to the EN 17037 EU standard.

• The quality of the view available from the interior of a flat greatly affects the value of a property. Flats and apartments within the same building may have equal floor area and layout, yet the quality of the offered view may differ greatly.
• A view to the outside provides information about the environment, weather changes, and the time of day, which can relieve the fatigue associated with long periods of being indoors. All occupants of a space should have the opportunity for relaxation afforded by a change of scene and focus.
• The European standard provides benchmarks and various methods to evaluate the quality of view out during the design phase of the building, as well as to verify the view out level of existing interior spaces.
• The view out level is assessed from a given position and depends on the horizontal sight angle, the distance of outside view, and the number of visible layers of the exterior environment. 
• The quality of the view depends on the width of the viewing angle (the size of the window), the distance, the number of distinct, visible layers (sky, landscape, ground), and the quality of the environmental information of the view.