Assessing the European Daylight Standard: A Simulation-Based Study of Daylight, Energy, and Thermal Loads in Swedish Residential Buildings

Abstract

Standards play a significant role in shaping our environment and everyday life. In the context of the built environment, they ensure consistency of quality between different projects. The European Daylight Standard EN17037 “Daylight in buildings” is one of those standards, currently in use in the European Union, and was established to secure enough natural light indoors to achieve spaces that are both bright enough and offer occupants views of the outdoor environment. However, it has been established that it is excessively ambitious and lacking in variability and adaptability regarding the diverse daylight conditions that are encountered in Europe.

The aim of this master thesis is to examine the mismatch between the European Daylight Standard’s recommendations and the reality of the built environment in Sweden’s largest cities. Initially, an extensive background regarding daylighting history and practices, as well as recent energy policies in Europe is provided to set the theoretical framework of the thesis. Then, daylight provision, energy consumption and indoor thermal comfort are simulated for 28 different buildings, located in Stockholm, Gothenburg and Örebro. Compliance rates with the European Daylight Standard are determined, as well as energy classification per building and overheating in indoor spaces during the summer. Then, five buildings, representative of different typologies, and least compliant with the European Daylight Standard, are selected and their openings are enlarged to provide more light. The impact of this measure on daylight, energy consumption and indoor overheating is simulated again and reexamined. Finally, daylighting, energy and overheating behavior trends in different typologies and urban contexts are discussed, and conclusions and general suggestions for the standard are made.

Popular Abstract

Only a quarter of rooms in typical Swedish apartment buildings meet the EU’s daylight standard — even after doubling the size of the windows. This thesis from Lund University shows that the European Daylight Standard (EN 17037) may be too ambitious for Sweden’s urban reality.
The standard aims to ensure bright, healthy homes with views to the outside — but it doesn’t account for the dense urban fabric or older buildings common in Sweden. In this thesis, computer simulations are used to test daylight access, energy use, and indoor thermal comfort in 28 multi-family buildings in cities like Stockholm and Gothenburg.
The results were striking: none of the buildings tested achieved 100% compliance. Only 27.5% of over 3,000 rooms passed the minimum daylight requirement. In the most extreme cases, not a single room qualified. As a second phase to the project, five of the worst-performing buildings were selected and their window sizes were doubled — a bold and expensive move. Still, the improvements were small to modest — and the buildings failed again to reach the standard’s minimum recommendations.
Bigger windows also meant more heat loss in winter and overheating in summer. Swapping to high-performance glazing helped, but even then, the gains in daylight were small.
The conclusion is clear: a one-size-fits-all rule doesn’t work. Standards like EN 17037 need to adapt to different climates, building types and functions, and urban conditions. Otherwise, architects and construction professionals are left chasing impossible targets — and residents are stuck with uncomfortable homes.

• author: Chatzikonstantinou, Anastasia
• supervisor: Niko Gentile
• organization: Division of Energy and Building Design
• course: AEBM01 20251
• year: 2025
• type: H2 - Master's Degree (Two Years)
• subject: Technology and Engineering
• keywords: European Daylight Standard, Daylighting in Buildings, Building Energy Consumption, Building Energy Simulation
• language: English
• id: 9198185
• date added to LUP: 2025-06-13 08:41:51
• date last changed: 2025-06-13 08:41:51