Bringing into line

Ruth MacEachern’s prize-winning dissertation looked at whether ventilation regulations go far enough to meet the requirements of the Future Homes and Buildings Standards across the UK, Channel Islands and Republic of Ireland, and asked whether there is scope for a standardised approach to ventilation.

Ventilation is often seen as the forgotten service within the building industry, appearing to lag behind while other services move forwards. This has sometimes been attributed to the fact that if, for example, there is an electrical or gas fault, either the lights go out or there is a strong smell of gas. If there are structural issues, these can often be seen with the naked eye.

For ventilation, calls to manufacturers and specialists are often made when mould is discovered, there is a musty smell or there is significant moisture on the walls in a building. After cooking, bathing and general living the presence of moisture on a window or bathroom mirror and in the air as steam becomes part of everyday living.

Looking back to the Future Homes Standard consultation announced by the government in England in 2019, the key driver was to look at future-proofing building practices that had significantly altered in line with increased thermal efficiencies, availability of materials and often the use of volumetric off-site production. This highlighted the need for changes to Approved Documents: Part L, which initially took place in 2020 and again in 2022; followed by an uplift to Part F for ventilation including the introduction of a non-residential document; and finally the new Approved Document O for overheating mitigation, again in 2022.

Following this action from the government in Westminster, there was also a review of regulations in Wales and the introduction of the New Build Heat Standard in Scotland. This essentially leads towards a significant reduction in carbon emissions moving towards 2025, with further uplifts in building performance, and ultimately a future Net Zero Standard. Interim uplifts followed in 2022 to both Approved Document F: Means of Ventilation in England and Wales and the Building Standards Technical Handbook in Scotland.

As a result of the previous consultation this has created more of a focus into ensuring good ventilation and indoor air quality in buildings.

Uplifts and improvements?

It was from these that I wondered how far-reaching these changes would be and whether this would force other areas to consider making some much-needed updates. I did have some concerns that what was initially released as part of the consultation documents and what actually came into fruition could take more time to both understand and implement than previously realised.

The uplifts have definitely resulted in some positive movements towards change within the industry, including with other standards such as technical guidance from the National House Building Council (NHBC) and the Passivhaus Standard. This has helped to continue to shape the future of ventilation in buildings, as well as providing safe, healthy and efficient homes not only for new builds but also change of use and retrofit works – something that hadn’t been considered in great detail when it came to previous versions of ventilation regulations.

From looking at the different sets of these regulations currently available, there seems to be an emerging trend – areas where the built environment or housing was a significant concern in terms of requirements and carbon emissions have made the leap and modernised their Approved Documents and thus their building standards.

I found this to be the case in England, Wales and Scotland. These updates were certainly welcomed when announced, if not before time – however, Scotland looked to take this one step further with MSP Alex Rowley proposing that “all new build housing” should “meet the Passivhaus standard or Scottish equivalent”.

Scotland’s Passivhaus plan

Originally devised in Germany by Dr Wolfgang Feist and Bo Adamson in the early 1990s, Passivhaus properties are often on the verge of being airtight with high levels of insulation. These properties also require mechanical ventilation with heat recovery (MVHR) as standard to ensure that both energy consumption is minimised and that the occupants of the property have ultimate comfort with continuous, filtered ventilation. The Scottish government determined that its own independent standard was needed as “without action at a UK level” steps must be taken “within the competence of Scotland’s fully devolved building regulations” – suggesting that the current proposals and standards elsewhere are not enough to be able to move forwards to meet net-zero targets.

In 2023, Edinburgh was chosen as the location to hold the UK Passivhaus Conference (at which I was in attendance). This event bolstered Scotland’s drive to implement the standard – a huge jump for ventilation and the standardised use of MVHR in new build properties. However, there were mixed reviews relating to the cost and output of a Passivhaus property, with reports from Midlothian Council that it had paused the policy of building Passivhaus homes “after it emerged that these cost £150,000 more per unit than regular homes”, with a single property “estimated at £341,456” with non-Passivhaus homes nearby “estimated to cost just £182,886 each”.

Following the conference and mixed reviews over the feasibility and costs of implementing an equivalent standard, the Scottish government announced a consultation towards the end of 2024, followed by another more detailed consultation in 2025. These concluded that the “current regulations and mandatory standard … already provided the means to deliver the [necessary] improvements”; however, more changes are required to “enable more effective reporting of evidence”. I have noted that it was then announced that the revised standards are set to be published in early 2026, but with no mandatory requirement until 2028 to allow for upskilling, resulting in further setbacks for improved ventilation provisions.

Old standards

Conversely, looking towards Northern Ireland, the Republic of Ireland, Jersey and Guernsey, I found that these areas are still working to regulations going back as far as 2013 – particularly when it came to ventilation and overheating, which has become a wider issue in recent years. The Climate Change Act in the UK, and ultimately the Paris Agreement that much of this initially stems from, covers all of the countries and crown dependencies listed. With this, and the legality behind it, in mind, it would seem that a unified effort could perhaps be the solution to ensuring a standardised level of acceptable building practices. These include the use of appropriate ventilation based upon increased levels of thermal efficiency and retrofit works to bring these older, draughty properties towards more modern and increasingly airtight solutions.

However, from reading further into the Building Bye-laws, Technical Booklets and Standards, it almost feels as if these increased uplifts and building practices are not a priority. On digging into this a little further and looking at the carbon reduction targets, I found that neither the built environment nor housing emissions concerns feature in the top emissions categories for any of these geographical areas. Therefore, it could be said that there is less pressure in relation to the built environment – instead, the priorities are transport, agriculture and alternative energy sources.

I also found that due to the age of these documents, they also assume the generalised housing stock is less airtight as per previous building practices, thus has more leakage and a lower thermal efficiency – which is exactly what is trying to be avoided or at least bettered with the Future Homes and Buildings Standards. The ventilation types that were therefore recommended were those seen in previous versions of technical guidance in line with increased air permeability levels such as the generalised use of intermittent fans, plus lower whole dwelling ventilation rates and background ventilation requirements.

To look into this further, a series of interviews were conducted with those working within the built environment across the countries and crown dependencies. It was universally accepted that not enough was being done to promote uplifts both to ventilation and in general, but that there had been the promise of improvements over the incoming 12-18 months (as of autumn 2023). When a combined effort was suggested, this was not seen as being an option due to both the Republic of Ireland remaining within the EU and the variance of these regulations in line with the local climate, general differences in housing stocks and government changes to policy.

It is well known that there is a significant skills shortage within the industry, as well as advances being made to ensure an increased level of competency. And with these incoming standards expected before the end of 2025 in England, and others set to follow, I feel that they must be fit for purpose to be able to carry forward the next generation of construction practices across all areas – not just those where the built environment comes ever so slightly further up the list of priorities.

This is also true for the changing strategies and targets implemented by the Climate Change Committee, such as the recent terming of a “balanced pathway” breaking down emissions by sectors to ensure that the targets are “achievable and cost-effective”, as well as differing net-zero targets.

Even though a unified approach isn’t an option, there still needs to be a collective vision as to how the built environment and regulation better uplifts our buildings and the health of the occupants. As the forgotten building service, the importance of the provision of ventilation needs to continue to increase in terms of being a priority for surveyors, housebuilders, architects and contractors. This also needs to feed out across the industry as part of a collective effort to become a true part of the building process. For both these standards and the importance of ventilation provisions within the industry, I still feel that there is a long way to go.

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