PART F · Ventilation
Part F building regulations explained
Part F concerns ventilation. Buildings need a suitable means of removing pollutants and moisture while providing fresh air. Opening a window occasionally is not a complete explanation of the ventilation design.
How does a home receive ventilation
The approach may combine background ventilation, extract ventilation and rapid ventilation, or use an appropriately designed mechanical system. Different systems rely on different components.
The designer should explain the whole arrangement. Adding a strong bathroom fan without considering replacement air can leave the overall system poorly coordinated.
Does every room need the same arrangement
No. Kitchens and bathrooms generate moisture and other pollutants, while living rooms and bedrooms have different needs. The system must suit the dwelling, occupancy assumptions and proposed work.
New construction, extensions and replacement windows can raise different questions. Existing ventilation should be assessed before airtightness improvements are made.
Which guidance applies now
As at 8 October 2026, the 2021 guidance remains the main current baseline, subject to applicable transitional arrangements. A 2026 dwelling edition has been published for the forthcoming standards. The associated changes generally commence on 24 March 2027, with later commencement for specified higher-risk building provisions.
Record the applicable version for the project rather than simply choosing the newest PDF.
What should happen at completion
Relevant systems need appropriate commissioning, checks and information for the owner. Ask for the ventilation settings, test records and instructions before the contractor leaves.
Filters, vents and controls need to remain accessible and understandable. Occupants are more likely to use a system correctly if they know what should run continuously and what needs maintenance.
Part F ventilation should be coordinated with Part L energy performance and Part C moisture protection. Closing vents to make a room warmer can undermine the design the building relies on.