Commercial Skylights Blog

Why is climate-based daylight modelling important?

Why is climate-based daylight modelling important?

Daylight modelling is the process of undertaking calculations to assess daylighting in respect of a particular building design. Because the number of daylight hours and angle of the sun varies by location, it’s important to carry out those calculations based on site-specific conditions. Climate-based modelling, therefore, is a technique developed to assess daylight provision based on building-specific location and orientation, and 365-day climate data.


When should climate-based daylight modelling be carried out?

When looking to meet the recommendations of EN 17037 ‘Daylight in Buildings’, climate-based daylight modelling is essential. It is also required as part of the Education and Skills Funding Agency’s (ESFA) Facilities Output Specification 2017, which forms part of Generic Design Brief for the Priority School Building Programme.

Daylighting can be a daunting concept to think about when designing a building, but it doesn’t need to be. While it is undoubtedly a complex subject - especially when accounting for the four different areas of daylight design covered by EN 17037 - seeking advice at an early stage and getting the benefit of daylight modelling calculations will smooth the process considerably.

The alternative is to avoid the cost of calculations and modelling exercises, because it seems like a saving. But if late changes have to be made to a design because something was not given proper consideration at the outset, the knock-on effects can prove even more expensive.

Using daylight modelling to help refine the client’s brief means the balance of facade glazing and roof glazing can be part of initial design concepts, addressing any overheating concerns and keeping electric lighting demand to a minimum. When whole-building performance is eventually addressed, these benefits will contribute to a positive outcome.


Which areas of EN 17037 is climate data most critical to?

Climate-based modelling is the preferred method for calculating daylight provision, or illuminance levels. This determines whether users can carry out tasks satisfactorily, and plays a part in determining the likelihood of artificial lighting being switched on. Daylight factor calculations can be used, but are less accurate.

Detailed calculation of daylight glare probability (DGP) - which is concerned with removing the probability of glare for building users, especially those who do not choose where they sit - is also more accurate using climate-based modelling.


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How are VELUX Modular Skylights different to other skylight systems on the market?



Is EN 17037 mandatory?

EN 17037 ‘Daylight in Buildings’ is not mandatory and so, like any code of practice adopted in the British Standards system, its contents constitute guidance and recommendations only.

However, the more a standard is adopted by and used within industry, the more authority it carries. As expectations increase that projects will demonstrate ‘compliance’ with the standard, meeting its recommendations effectively becomes mandatory.

How is adoption of a standard driven?

Standards can be quoted in regulations, and following the guidance in the standard is then taken as demonstrating compliance with the regulation in question. This is often what drives architects and other design professionals to meet a standard, and name it on drawings and in specifications.

When it comes to EN 17037, the provision of better daylighting in buildings is very much an issue of occupant comfort and wellbeing. Increased adoption could therefore come from a variety of sources. Architects and specifiers might choose to promote it to their clients as part of better building design generally.

In a lot of cases, working to certain standards is a client-driven requirement, like achieving sustainability benchmarks. As awareness of EN 17037 grows, it will likely find its way into assessment schemes like BREEAM or WELL, where credits will be awarded for meeting its guidance.

Sectors such as education and healthcare could also see EN 17037 adopted in government-issued guidance for the design of schools, hospitals and similar buildings. Local education bodies and health authorities would then have the freedom to specify that the standard be adopted.

Is it possible to achieve ‘compliance’ with a standard?

When it is desirable to achieve certain recommendations set out by a code of practice, project drawings or specifications may feature the phrase, “to comply with …” or, “in accordance with …”. However, care must be taken about claiming compliance with a standard or code of practice that is not mandatory.

That’s because the guidance of one part of the document might be met, but the project may not meet recommendations set out elsewhere in the standard.

If a dispute arises and the project is claimed to be ‘compliant’ with the standard, but cannot be shown to meet all of the relevant recommendations, then it may become necessary to justify why certain decisions were taken that did not follow the standard.


How do VELUX Modular Skylights help to reduce risk on Site?

The two most important factors to consider when safely incorporating skylights into a development are the safe installation of the units and the efficiency of the process. Using VELUX Modular Skylights creates benefits for installers and main contractors alike. Thanks to the prefabricated and modular nature of the skylights ( and the different module configurations), rapid installation and minimal preparatory works are required to safely install the units at height.


How can VELUX Modular Skylights help contribute towards the sustainability of your building?

Modular skylights are produced with the changing nature of the environment in mind, helping contribute towards the sustainability of your building.

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How do VELUX Modular Skylights help to reduce running costs and carbon emissions of a building?

Modular skylights are an affordable way to reduce the carbon emissions and running costs of a building.

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Why is daylight and ventilation important in office spaces?

Due to the amount of time the average person spends working inside offices, daylight and ventilation have an enormous impact on peoples’ health and well-being as well as improving productivity.

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