Ventilation requirements in Wales

How is home ventilation regulated in Wales?

Wales has its own Approved Document F, published by the Welsh Government, which sets the ventilation new and altered homes must have. It took effect on 23 November 2022. The approach closely follows the same principles as England, with minimum extract rates for wet rooms and a whole-dwelling ventilation rate, but it is maintained separately by Wales and applies on its own timeline.

Since building regulations were devolved, Wales publishes and updates its own Approved Documents. For ventilation the Welsh document is closely related to the English one but is a separate publication, so the version and effective date differ. For a Welsh project it is the Welsh document that applies.

Sources: GOV.WALES

How do Wales ventilation rules differ from England?

The Welsh and English Approved Documents F are closely related but separate. The main practical differences are the timeline, Wales came into force on 23 November 2022 rather than 15 June 2022, and that Wales introduced a new Part O for overheating alongside the changes. The Future Homes Standard is an England measure; Wales sets its own future path. Use the Welsh document for a Welsh project.

For most homeowners the day-to-day ventilation requirements feel similar across the border, because the Welsh document follows the same structure. The differences that matter are which document and version applies, the effective date, and the additional overheating requirement, so a designer working in Wales should reference the Welsh publications.

What is Part O in Wales?

Part O is a building regulation covering overheating in new residential buildings, introduced in Wales alongside the 2022 changes, as in England. It requires new homes to be designed to limit overheating, which interacts with ventilation because ventilation is one of the ways a home sheds heat. It is separate from Part F but related.

Overheating and ventilation are linked, because purge ventilation and a summer bypass on an MVHR system are among the ways a home stays comfortable in hot weather. Part O sets the overheating requirement, and the ventilation strategy has to work with it. A new Welsh home is assessed against both.

What ventilation does a Welsh home need?

A Welsh home needs ventilation to the Welsh Approved Document F: minimum extract rates for kitchens, bathrooms and other wet rooms, and a whole-dwelling supply of fresh air, provided by natural or mechanical means including MVHR. For the exact rates that apply to your project, refer to the Welsh Approved Document F, as it is maintained separately from England.

Because the Welsh document is closely based on the same approach as England, MVHR, continuous extract and natural systems are all recognised routes to compliance. The safest step for a Welsh project is to use the Welsh Approved Document F for the specific figures rather than assuming the English ones apply unchanged.

Sources: GOV.WALES