What Part F and the Future Homes Standard Mean for Ventilation in 2027

In England, the regulations will be introduced across 2 dates: 
•    24th March 2027 for standard new build work.
•    24th September 2027 for higher risk work.

Note that this is outside of any works under transitional protection.

There will be a single implementation date in Wales – 4th March 2027. Again, except for works outside of transitional protection.

The Future Homes Standard mandates that all new-build homes produce 75-80% fewer carbon emissions than the 2013 baseline. This is a transformational shift, requiring developers to rethink their approach to energy performance from the very earliest design stages. Because of the move to increased efficiency and airtightness, ventilation will become an even more critical building service. If properties are not ventilated correctly, the risk of indoor air pollutants and excess moisture increases significantly.

Energy Efficiency for Ventilation Products

As part of the Future Homes Standard, Specific Fan Power (SFP) limits for domestic ventilation are tightening significantly in updated building regulations to match higher airtightness and energy efficiency demands.

SFP measures the electrical efficiency of a ventilation system. It is assessing the energy required to move a given volume of air. Typically, SFP is measured in Watts per litre per second (W/l/s). Lower values mean better efficiency.

New SFP Limits:

• Continuous Mechanical Extract Ventilation (cMEV): Tightened to a maximum of 0.5 W/l/s for new builds and 0.7 W/l/s for existing building refurbishments.
• Decentralised MEV (dMEV): Assigned a distinct standalone maximum value of 0.3 W/l/s
• Mechanical Ventilation with Heat Recovery (MVHR): Adjusted to a maximum of 1.4 W/l/s for new builds and 1.5W/l/s for existing builds.

Higher Quality Ductwork

Changes will come in to ensure that ventilation systems are more efficient in operation. These changes could have impacts on MVHR, cMEV and dMEV ducting designs.

The revisions will require:

• The use of ‘rigid or smooth semi-rigid ducts’ for centralised continuous mechanical extract ventilation and MVHR systems
• Rigid ductwork for intermittent and d-MEV fans with the ‘maximum length of ducting being 2.0m where practical’
• The length of flexible ductwork to be limited to 200mm and ‘only for final connections to fan unit spigots’ for c-MEV and MVHR systems.

It is prudent that these changes are thought through at design because implementation at build stage can be extremely difficult.

Testing and Commissioning

It is increasingly critical that a ventilation system is performing as designed. Given this, there are a number of changes in the new standard which focus on demonstration of system performance.

Powered flow hoods must be used for commissioning new ventilation systems and rotating vane anemometers will no longer be permitted, apart from for Intermittent extract fans.

For new properties, airflow test and commissioning results are expected to be provided to Building Control within five days of the final test. Testing requirements may also apply to certain new systems in existing properties, including new c-MEV systems, major changes to these systems and some mechanical ventilation fans with longer or more complex ductwork.

Competent Installers

Approved Document L has introduced Regulation 11F in England and 11W in Wales, which places clear requirements on competence when carrying out building work or design work.

There is now clear guidance that greater care should be taken when installing a mechanical ventilation system, particularly centralised systems, and to ensure that both the following are met: a. “The person carrying out the work is suitably competent (for example, they are a registered competent person). b. The work meets the requirements of the Building Regulations.” 

For ventilation, Approved Document F also makes clear that work should be carried out by someone suitably competent, either through self-certification or by a registered competent person or certification by a Building Control Body. Registered Competent Person schemes include BPEC’s Domestic Ventilation Systems course. This is a training/assessment course which is ideal for experienced electricians, plumbers, ventilation installers and heating engineers looking to improve their knowledge and understanding of domestic ventilation systems. The course has been structured to meet the requirements of the Approved Document Part F of the Building Regulations 2020 and is recognised as a demonstration of competence for Competent Person Schemes (CPS).

Resident Handover

The final changes are around information provided to residents. The wider 2026 Future Homes and Buildings Standards introduce Regulation 40C, which requires information about the building and its systems to be provided to the homeowner in an appropriate format. Approved Document F links its ventilation requirements to this new handover obligation, while the detailed requirements for the Home User Guide are set out in Approved Document L.

The updated guidance includes expectations around fan checks, inspections, maintenance, commissioning and summer bypass testing for MVHR systems.

The aim is to give the ventilation system the best possible opportunity to perform in the way it was designed once the property is occupied.

In Scotland, Building Regulations are enforced through Domestic Technical Handbooks. Scotland introduced the New Build Heat Standard on 1 April 2024, which banned direct-emission (fossil fuel) heating systems in new builds.

The Future Home Standard will update Building Regulations Part F and Part L directly. As a result, the changes are not confined to new build sites only – significant retrofit and renovation projects are included too

If work significantly alters a building’s fabric, energy efficiency or ventilation then it will fall under the regulations. This involves a 50% threshold where any completely new element must comply with current standards as must any existing thermal element where more than 50% of its surface area is being renovated. However, projects such as modifying ventilation or replacing windows and doors all activate Part L and Part F obligations too.