Shaping healthier, brighter buildings: daylight, ventilation and overheating in rooflight design

Daylight is now recognised as a critical performance parameter in non‑domestic buildings, influencing energy use, comfort and occupant wellbeing. The Rooflight Association’s 2025 Daylight White Paper brings together research and industry practice to show how considered rooflight design can support circadian rhythms, concentration, staff retention and reduced absenteeism, as well as lowering electrical lighting demand.

As a Rooflight Association board member, VELUX Commercial UK&I’s Sales Director, Paul Reid notes: “Daylight is essential to supporting alertness, concentration and overall wellbeing – innovative rooflight solutions are integral to making that happen.” For specifiers, the message is clear: rooflights are not an afterthought, but a primary tool in meeting human‑centric and energy‑performance objectives.

Competing roof functions and “Battle of the Roofs”

The first episode of the VELUX Commercial UK&I podcast series, Battle of the Roofs: Daylight & Wellbeing, reflects a familiar tension for specifiers: PV, blue and green roofs, plant and access all compete with openings for daylight and ventilation. The discussion reinforces a key conclusion from the White Paper – that even relatively modest rooflight areas (for example around 12% of roof area) can deliver significant daylight autonomy when optimised through climate‑based modelling. Early allocation of roof area for rooflights is therefore essential if daylight targets under EN 17037, WELL or project‑specific briefs are to be achieved.

Overheating, Part O and non‑domestic buildings

While UK Building Regulations Part O currently focuses on new dwellings, overheating is also a live issue in schools, offices, healthcare and industrial buildings. Studies suggest that around 80% of UK homes are at risk of overheating during summer, and similar trends are emerging in other building types. For specifiers, the challenge is to provide adequate daylight and views while controlling solar gains and enabling effective purge and background ventilation.

An integrated approach

VELUX Commercial takes an integrated approach through its Modular Skylights (VMS), Vertical Glazing Panels (VGP) and associated control options, supported by daylight and overheating modelling. Using tools such as VELUX Daylight Visualiser and virtual modelling services, the design team can test rooflight size, spacing, glazing specification, opening configurations and internal blinds at concept and developed design stages. This helps specifiers balance daylight factors, U‑values, g‑values and airflow rates against overheating risk and compliance requirements.

Modular Rooflights can be supplied pre‑wired for internal blinds or specified with solar‑control or low‑g glazing, enabling dynamic management of solar gains and glare via building management systems. Natural smoke and heat exhaust ventilation (SHEV) variants allow life‑safety and comfort ventilation functions to be combined where appropriate.

Collaboration and technical support

VELUX Commercial’s role typically begins at early design, providing layout options, daylight and glare assessments, and overheating risk commentary based on project data. CPD modules such as Daylight and the Human Response and Roof Glazing: More Than Just Glass give design teams an overview of current evidence, standards and best practice. The podcast series extends this with discussions on daylight, wellbeing, safety and compliance, giving specifiers additional context in an accessible format.

With roof zones under increasing pressure from energy and resilience measures, the risk is that daylight is progressively compromised. The combined message from the Daylight White Paper and Battle of the Roofs is that early, evidence‑based decisions on rooflight strategy allow specifiers to meet energy and overheating requirements without sacrificing the quality of the internal environment.

Have a project in mind? Explore our services online!

https://commercial.velux.co.uk/service-and-support?utm_source=website&utm_medium=textlink&utm_campaign=specification_january_2026

Contact information: sales@veluxcommercial.co.uk +441670 354157