Light provided by the sun is divided into direct sunlight and diffuse skylight; light modified and distributed by the atmosphere. Daylight quality and intensity depends on: - Geographical latitude - Month and hour of a day - Local weather - Sky conditions - Building geometry
Glare is defined as the condition of vision in which there is discomfort or a reduction in the ability to see significant objects due to an unsuitable distribution or range of luminances. Discomfort glare indices are based on: - The luminance of the glare source(s) in the field of view - The solid angle of the glare source(s) - The luminance of the background - The position index of the glare source(s)
Daylight and glare
With increasing concern over global warming and carbon emissions, monitoring the level and quality of natural light in buildings plays a pivotal role in environmental programs and design, such as BREEAM, LEED and Home Quality Mark.
Daylight and glare expertise
We carry out assessments for every hour in the entire year. Our dedicated team have many years of experience investigating the effects of different parameters on daylight and discomfort glare prediction.
To review daylight and glare impact within the built environment, we carry out daylight assessments that compare the impact of building orientation, window frame factor, window size, overhang and G-value on daylight quality and intensity. Our team can provide innovative and sustainable integrated daylighting with efficient electric lighting strategies to provide substantial energy savings.
Positive effects of daylight
Biological effects – Daylight can affect our biological clocks, sleep and activity. Many manufacturers are using artificial lighting to simulate external conditions to prevent diseases, stress, fatigue and tiredness.
Thermal effects – Window and lighting systems can affect building thermal loads. Having lighting control systems can reduce the cooling demand; such as decreasing lux when daylight watts are enough or using shading devices when the room is not occupied in the summer, and reversing this in winter.
Energy saving – In the built environment, we benefit from using solar energy in various ways, such as heating and lighting. Building energy consumption can also be reduced by daylighting, a strategy in modern architecture where natural light openings are factored into design to replace or supplement artificial lighting. Daylight itself does not increase energy saving but when paired with lighting control strategies (manual, timed and automatic controls) or photo sensors it can significantly lower energy costs.
What you need to know about daylight and glare
- It is important to integrate disciplines to streamline daylighting design, including architectural, mechanical, electrical and lighting. Teams should be brought into the design process early to ensure that daylighting concepts and strategies are implemented throughout.
- The lighting system must correlate to the various systems in place, including structural, curtain wall, ceiling, and furniture. The building's planning module can often give indications on how best to organize the lighting.
- Initial lighting costs may rise when designing for sustainability and implementing energy-efficient strategies. These energy-saving designs may require items such as dimmable ballasts, photocells, and occupancy sensors, all of which are not typically covered in most traditional project budgets. However, these items are normally included if an integrated design approach is employed and if daylight strategies are appropriately employed at an early phase of the project's design.
- Glare should be considered when contemplating the massing of a building or a larger development. This requires evaluating the geometries and surfaces of neighbouring buildings with specular facades, potential secondary and tertiary reflections, the Earth’s movement in relation to the sun, local topography, viewing points, and types of public and transport spaces.