Daylight Under New Rules: What BBR 31 Means for homes in the future

09/01/25

by Alexander Perez, Nordnest

Daylight: The Hidden Force in Our Homes

Daylight is more than just a pleasant feature. It shapes health, sleep, energy use and even influences the sustainability of buildings.

Research shows that access to natural light can:

  • Reduce stress
  • Improve concentration
  • Support our circadian rhythm
  • Lower household energy demand

In other words, daylight is both a human need and a building performance factor.

A New Playing Field

For years, the Swedish National Board of Housing, Building and Planning set strict rules: every room where people spend time like bedrooms, living rooms and kitchens had to achieve a median daylight factor of at least 1%.

On 1 July 2025, the new BBR 31 came into force. Now the rules are different:

Only 50% of the total floor area of habitable rooms needs to reach a daylight factor of 1%. This means not every individual room needs natural light anymore. In practice this means a kitchen or a bedroom could be left dark if another space balances it out.

This is a game-changer for both residents and those designing our homes.

Why the Shift?

The aim is flexibility. The old rules were tough to meet:

  • Renovations often couldn’t comply without drastic changes
  • New builds in dense urban areas struggled due to overshadowing
  • Fixed layouts sometimes made compliance impossible

By measuring daylight at the dwelling level instead of room by room, BBR 31 makes it easier to adapt older housing stock and approve new projects in challenging contexts.

What the Research Shows

A 2025 FOJAB study puts numbers on the change.

Analysing 675 rooms across 248 flats with poor daylight conditions, the study found:

  • Under BBR 30: 46% of dwellings passed
  • Under BBR 31: 75% passed.

It also showed that:

  • 30% more flats on critical floors now meet requirements
  • Through-apartments (with multiple orientations) benefit most
  • Deep structures and dense plots still struggle.

And when residents were asked:

  • They were most willing to accept a darker bedroom.
  • They were far less willing to accept a dark kitchen or living room.

So, while more dwellings will now pass, some homes may contain spaces that feel unexpectedly gloomy.

What This Means in Practice

For residents, the change could be surprising. Imagine moving into a brand-new apartment and finding a kitchen without windows which was impossible under the old rules.

For architects and developers, the regulation opens new opportunities:

  • More creative layouts
  • Greater efficiency in space use
  • Smoother approvals in dense urban sites or renovations

Lessons From Daily Practice

Those of us who work with daylight daily through simulations, planning applications and environmental certifications see both the opportunities and the challenges.

Used well, daylight can:

  • Strengthen health and wellbeing
  • Reduce energy use with free solar gain and at the same time avoid overheating when designed smartly
  • Improve project economics at the same time

Used poorly, the result is clear: dark rooms, compromised quality of life and less energy efficient buildings.

Conclusion: Finding the Balance

Daylight is something we only notice when it’s missing. With BBR 31, daylight is no longer guaranteed in every room, but the regulation does open new possibilities.

Research suggests more dwellings will pass approval, but also that more dark rooms will appear. The responsibility now shifts to us in the industry.

It’s not just about following what’s permitted. It’s about finding solutions that satisfy residents’ expectations, clients’ needs and long-term sustainability.

At Nordnest, this is our focus: treating daylight as an opportunity. By balancing comfort, economy and sustainability, we design homes where light, function and economy work together in the best possible way.

The new rules change the game. The challenge and the opportunity is to make sure daylight continues to make life brighter.