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Sixty-year-old regulations regulate daylight requirements of Finnish residential buildings

Industry & Insight
July 15, 2022

Hanna Vikberg, architect at Tengbom Finland and Raoul Lindberg, Product specialist sales executive at Spacemaker shine the spotlight on daylight, and why architects and urban planners can give it the attention it deserves during early phase planning. 

In Finland, the daylight conditions of residential buildings are defined by regulations from 1959. These regulations define daylight conditions, the distance of buildings to other buildings, their height and the ratio of the window area to the floor area.

Currently, one trend in residential construction is to maximize the square meters per stairwell in buildings, which easily leads to wider structures. As a result of this, dwellings become deeper than before which in turn affects the amount of daylight available to the interior. The question is, does Finnish housing construction industry pay enough attention to daylight?

As cities densify and building heights increase, the role of daylight becomes more important. In addition to needing good light conditions for practical reasons, there are also positive health effects of daylight: it affects a person's circadian rhythm, hormone production and sleep quality, among other things. While artificial lighting provides illumination, it does not contribute to the health effects of natural light.

Hanna Vikberg, architect at Tengbom, Finland

The impact of light is greater than numbers

When we talk about daylight, we often incorrectly think of direct sunlight. However, direct sunlight is not the most important light source in Finland, but diffuse light. Diffuse light refers to light that filters through clouds, for example, even when the sun doesn’t shine. In 2018, a European standard has been published on how daylight should be calculated and at what level it should be in different spaces.

In Finland, however, these standards are not mandatory, so they are not followed. Thus, in construction, our daylight conditions are defined by 60-year-old regulations. Nordic people spend up to 90% of their time indoors, which means that it’s vital to take daylight into account when designing buildings.

Daylight is mostly evaluated numerically, allowing concentration to be easily focused on the amount of light. In this case, many other factors affecting the quality of light, such as its effects on the space and user experience, health and energy consumption, are easily overlooked.

The numerical approach takes little account of the user experience such as how the living space is perceived: does the space feel pleasant? Does it offer an ambience or perhaps a connection to nature? Experience is hard to measure through KPI’s, and no answer has yet been found as to why a person perceives daylight as so important.

More holistic urban planning also takes daylight into account

Residential construction does not give light the attention it deserves. Although light is known to be important, there is little taught about it in universities. Nor is it given much thought in the software used by builders and architects. Does the reason behind the neglect of light lie in budget, and access to the right tools and data?

If the amount of light is already taken into account at the design level and as part of overall urban planning, it shouldn't affect the project cost. The greater impact on cost is seen when you try to solve daylight issues too late in the process, such as in the design of balconies, colors of the materials and size of the windows.

Of course, taking light into account also requires integrating this expertise into projects, which can be challenging due to a lack of training. Fortunately, a solution has already been developed for this problem. Norwegian-based software provider Spacemaker, an Autodesk company, has an easy-to-use integrated daylight analysis tool that makes light optimization easier in the early phase. If daylight is analyzed and considered as early as possible in the design process when high impact decisions can be made with little cost, it can save money, avoid project delays due to rework or retrofitting and create better living conditions that can improve the wellbeing of people. 

Test Spacemaker's daylight analysis on your own project in a free trial.

The article references a study on methods for assessing and controlling daylight conditions (2019) authored by Hanna Vikberg, Kimmo Lylykangas and Francesco De Luca.

Image credit: Tengbom/Kuvio

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