As buildings become increasingly airtight and energy-efficient, ensuring adequate indoor air quality is vital to occupant health and building performance. In the UK, Approved Document F provides statutory guidance on how to meet the ventilation requirements set out in Requirement F1 of Schedule 1 of the Building Regulations 2010.
This guide offers a practical overview of how to comply with Approved Document F covering both dwellings and non-domestic buildings, and demonstrates how Inbuild UK’s range of ventilation solutions can support compliance.
What Is Approved Document F?
Approved Document F (ADF) is split into two volumes:
-
Volume 1: Dwellings (for new and existing residential buildings)
-
Volume 2: Buildings other than dwellings (offices, schools, commercial properties, etc.)
ADF outlines acceptable methods for achieving adequate ventilation to ensure the removal of pollutants and moisture, and to maintain indoor air quality.
The latest guidance (2021 edition with 2022 amendments) reflects greater emphasis on:
-
Energy-efficient buildings with reduced air permeability
-
Mitigating risks of condensation, mould, and airborne pollutants (e.g. CO₂, VOCs)
-
Integrating mechanical ventilation and monitoring solutions
Why It Matters
Poor ventilation has been linked to health issues including asthma, fatigue, and respiratory infections. Moisture build-up from cooking, washing, and even breathing can create damp and mould conditions that risk occupant wellbeing — especially in airtight, modern properties.
ADF compliance is now closely monitored during design and construction. Failure to comply can result in non-compliant handover, enforcement notices, or costly remedial works.
Key Requirements by Building Type
New Dwellings (Volume 1)
Approved Document F sets out four recognised ventilation systems:
-
System 1: Background ventilators and intermittent extract fans
-
System 2: Passive stack ventilation
-
System 3: Continuous mechanical extract ventilation (dMEV)
-
System 4: Mechanical ventilation with heat recovery (MVHR)
Ventilation must meet minimum whole-dwelling ventilation rates based on floor area and number of bedrooms. For example:
-
A 4-bedroom house (93–101 m²) requires 29 L/s continuous airflow (Table 1.3, ADF Vol. 1)
Extract ventilation is also required in:
-
Kitchens: 30 L/s adjacent to hob or 60 L/s elsewhere (intermittent) or 13 L/s (continuous)
-
Bathrooms: 8 L/s (continuous) or 15 L/s (intermittent)
-
Utility rooms: 8 L/s continuous or 30 L/s intermittent
Homes with a design air permeability of ≤5 m³/h·m² at 50 Pa must use continuous mechanical ventilation systems (System 3 or 4) to comply. This reflects the reduced natural air infiltration in energy-efficient homes.
Existing Dwellings (Volume 1)
When upgrading insulation, replacing windows, or undertaking extensions, ADF requires that ventilation is not made worse and must be retained or improved.
For example:
-
If trickle vents are removed during a window replacement, equivalent background ventilation must be reinstated.
-
Mechanical extract may be required if passive ventilation is insufficient post-upgrade.
Retrofit scenarios increasingly benefit from discreet dMEV or heat recovery units.
Buildings Other Than Dwellings (Volume 2)
ADF Volume 2 applies to offices, schools, retail units, healthcare premises, and more. Ventilation must:
-
Deliver at least 10 L/s per person or
-
Maintain indoor CO₂ levels below 1,500 ppm (with 1,000 ppm as the recommended target)
Where mechanical ventilation is used:
-
Systems must include controls and indicators to show correct operation.
-
Offices and educational buildings should have CO₂ monitoring in occupied areas.
For high-occupancy or enclosed environments, demand-controlled mechanical systems are often the most effective compliance route.
Products That Help You Comply
At Inbuild UK, we supply high-performance ventilation products that align with Approved Document F standards - supporting both compliance and healthy indoor environments.
Here are some of our most practical solutions:
A decentralised mechanical extract ventilation (dMEV) unit ideal for bathrooms, kitchens, and utility rooms. Designed for continuous operation, it provides compliant airflow in both new and existing buildings.
-
Quiet, energy-efficient and SAP Appendix Q listed
-
Fully compliant with System 3 (continuous extract)
-
Easy to retrofit in refurb projects
A compact unit that provides mechanical extract and fresh air supply with up to 85% heat recovery. This supports both energy efficiency and indoor air quality.
-
Ideal for bedrooms, home offices or living areas
-
No central ducting required — easy install
-
Supports System 4 compliance in smaller zones
An enhanced version of the Flux HR, with smart sensors for humidity and CO₂ levels.
-
Boosts ventilation automatically when air quality drops
-
Ideal for highly airtight homes or sensitive environments
-
Supports Part F compliance and IAQ monitoring expectations
Approved Document F is a cornerstone of safe, compliant building design - for both domestic and non-domestic properties. With a growing focus on airtightness and occupant health, choosing the right ventilation solution is more important than ever.
At Inbuild UK, we’re here to help you stay compliant, protect your clients and deliver better air quality every day.
Browse our full range of ventilation solutions:
Day-to-day ventilation
Need help selecting a product or planning for compliance? Our team is ready to assist.
