Sweden — BFS 2024:8
Legal status
Mandatory. BFS 2024:8 is Boverket's building regulation on light in buildings (Ljus i byggnader), in force under the Swedish Planning and Building Act (PBL). It replaced the daylight provisions previously in BBR. For workplaces, the Swedish Work Environment Authority adds a parallel requirement of its own — see AFS 2023:12.
BFS 2024:8 is published as SS-EN 17037 with a Swedish national threshold. The underlying calculation concept is the daylight factor, which expresses how much daylight reaches the inside of a room compared with the light outside under an overcast sky.
Requirement
| Item | Value |
|---|---|
| Metric | Daylight factor (DF) |
| Threshold | DF ≥ 1.0 % |
| Area that must pass | > 50 % of the assessed floor area |
| Assessment level | The dwelling as a whole — all vistelserum (habitable rooms) are pooled and assessed together, not room by room |
| Non-residential | Same DF ≥ 1.0 % / ≥ 50 % criterion is applied in practice, assessed per room; BFS 2024:8 does not state a separate number. Workplaces additionally fall under AFS 2023:12. |
Residential buildings
Dwellings must be designed so that the daylight factor is at least 1.0 % over at least 50 % of the total assessed floor area of all habitable rooms (vistelserum) — rooms where people stay more than temporarily. These rooms are assessed collectively at the dwelling level.
In shared/collective housing where the functions cooking, socializing and meals (matlagning, samvaro och måltider) are split between a private housing unit and a shared room, the DF ≥ 1.0 % / ≥ 50 % requirement must be met both in the individual housing unit and in the room for the shared functions — not just one or the other.
View out (utblick)
Separately from the daylight factor requirement, dwellings must provide a view of the outside (utblick) from the space used for socializing and meals (samvaro och måltider). This does not apply to shared social/dining spaces in collective housing made up of single-person housing units. LUX does not currently assess this requirement — it reports daylight factor only.
Other building types
For non-residential buildings, BFS 2024:8 sets a general requirement that rooms where people stay for longer periods must be designed to allow both sufficient daylight and a view of the outside, to avoid harm to people's health. The regulation does not give a specific number, stating instead that daylight shall be assessed depending on room use. This requirement does not apply if it would be unreasonable given the room's intended use or other circumstances. In practice the residential DF criterion (DF ≥ 1.0 %, ≥ 50 % of the area) is usually applied for the daylight part, assessed individually per room. Workplaces are additionally covered by AFS 2023:12, issued separately by the Swedish Work Environment Authority.
Spaces included and excluded
| Building type | Typically included | Typically excluded |
|---|---|---|
| Residential (vistelserum) | Bedrooms, living rooms, kitchens, dining rooms, home offices | Bathrooms, corridors, hallways, storage rooms, technical areas |
| Offices | Fixed workstations, defined desk areas | Aisles, break zones |
| Schools & healthcare | Classrooms, patient rooms | Lobbies without permanent staff, waiting areas, cafeterias, pantries, archives, technical rooms |
| Retail & hospitality | Restaurant kitchens, fixed indoor work areas | Areas where staff move continuously (shop floors, service areas) |
Example: BFS 2024:8 compliance assessment for a residential apartment. 63.3 % of the habitable floor area (vistelserum) achieves DF ≥ 1 %, exceeding the 50 % requirement.
Calculation setup
| Parameter | Value | Notes |
|---|---|---|
| Reference plane height | 0.8 m above floor | Not restated in BFS 2024:8; 0.8 m is kept by convention from the previous regulation |
| Grid spacing | 0.2–0.3 m | Not prescribed by the regulation; common practice |
| Wall offset (excluded border) | none | No perimeter border is excluded in current Swedish practice |
| Sky model | CIE standard overcast sky |
Reflectances are not mandated by BFS 2024:8; see Reflectance for the values LUX uses.
How LUX handles it
Status: ✅ Supported in LUX Live v0.3.0.
LUX Live reports BFS 2024:8 compliance automatically: for each dwelling it computes the share of habitable-room floor area at DF ≥ 1.0 % and flags the dwelling green (≥ 50 %) or red. This runs on the DF Default model — the only validated model, in production use — which is recommended as a replacement for preliminary daylight simulations, and for final verification where the project materials are equal to or lighter than the default set. The free IFC Daylight Factor tool gives the same DF result on default materials for early-stage checks. Per-surface project materials (DF Custom) are developed but not yet deployed; see Simulation modes.
Sources
- BFS 2024:8 — full regulation text (PDF) — Boverket, official legal text, incl. 4 kap. Ljusförhållanden (free)
- BFS 2024:8 — Ljus i byggnader / Dagsljus — Boverket, explanatory guidance (free)
- SS-EN 17037:2018 — Daylight in buildings — SIS (paid standard)
- See AFS 2023:12 for the parallel workplace requirement.