What BFS 2024:8 requires
Chapter 3, section 5 asks for ventilation systems in dwellings designed for an outdoor air flow of at least:
| Requirement | Minimum outdoor air flow |
|---|---|
| Per m² of floor area (golvarea) | 0.35 l/s |
| Rooms in dwellings, per person | 4.0 l/s |
Boost and cooking
Section 6 requires that increased air exchange is possible in dwellings, and that air pollution from cooking can be removed at the source.
Worked example
A home of 100 m² for four people. By floor area: 0.35 × 100 = 35 l/s. By persons: 4 × 4.0 = 16 l/s. Aira uses the higher value, 35 l/s (126 m³/h), as the total outdoor air flow.
How Aira applies it
Aira takes the total floor area from the plan and the number of occupants from the bedrooms (two in the largest bedroom and one in each other, shown as an assumption you can change), and uses the higher of the two requirements as the total outdoor air flow. Supply is divided over the habitable rooms by floor area and the extract equally over kitchen, bathrooms, toilets and utility room; supply and extract are equal. You can adjust every figure in the table before you download the plan.
Source
The figures are taken from the official text of BFS 2024:8 (issued 20 November 2024), checked on 16 October 2026. The regulation applies to new buildings.