Passive Ventilation: A Fresh Perspective on an Old Strategy

It’s well established the traditional workplace must change in the aftermath of COVID-19, but what does this mean beyond the interior layouts and flexible working schemes? 

A quick online search reveals the architectural spotlight which has recently been cast on air quality, from the impact of reduced industry and less road transport on outdoor air, to the role indoor systems can play in keeping people safe and thermally comfortable, post-Covid.

The growing awareness of poor indoor air quality’s negative effects has prompted holistic discussions around how a building’s design, layout and systems can deliver a healthier working environment.

Passive ventilation is one such strategy rapidly becoming a solution of choice for specifiers. Whether standalone or in a hybrid solution with mechanical systems, it has the potential to improve building occupants’ wellbeing, productivity and long-term health. Similar to other elements within the passive approach to design, it also benefits the environment, offering a lower-carbon option in comparison to pure-play mechanical HVAC. With an updated approach and cleverly designed smart controls, modern passive ventilation systems can be easier to design for and optimise than in the past.

Here I would like to take the opportunity not only to demonstrate why good air quality is important, but also to make the case for adoption of a passive design approach to ventilation. 

Bad air, bad news
The ongoing pandemic has emphasised that good air quality is beneficial for our health and well-being, and it’s put pressure on architects, specifiers and designers to step up to the plate. 

Symptoms of poor indoor air quality (IAQ) can range from increased allergies, asthma issues and light-headedness to headache and grogginess, called Sick Building Syndrome. At their worst, poor IAQ symptoms include stress, anxiety, poor mental health, serious pulmonary and respiratory disease and, in the extreme, death. The risks of inaction are closely linked to worker productivity and their company results. Reduced worker wellness, job satisfaction and stress and anxiety follow from these. No matter the place of work, blue or white.  

In April 2020, a Harvard survey of over 3,000 workers across 40 buildings found 57% of total sick leave could be attributed back to bad air. What’s more, the same study found better air quality could translate to an estimated £4,500-£5,400 of added annual productivity per employee. In large workforces, this amounts to a considerable amount of both money and, importantly, worker satisfaction.

It’s a serious issue, demanding better, more effective building ventilation solutions to encourage the flow of fresh, high quality air. 

Don’t pass on passive
Crucially, this better quality air also needs to be delivered in an eco-friendly way, in line with the UK Government’s drive towards Net Zero 2050. 

Along with protecting people, designing with better, more efficient ventilation is a key player in fighting climate change, reducing the impact buildings have on the environment. Operating emissions from energy used on lighting, heating and cooling account for 28% of all carbon emissions emitted by building and construction (which is 39%). 

Passive ventilation systems are one achievable solution to this ongoing issue and are gaining traction amongst specifiers and architects. 

Essentially, passive ventilation is the process of supplying and removing air from a space, with minimal or no mechanical aid. When appropriately designed and controlled, it harnesses the potential of natural elements, such as wind and thermal buoyancy, to regulate temperature and improve IAQ. 

Importantly, these strategies decrease reliance on carbon-intensive, purely mechanical systems, reducing a building’s operational emissions and, in turn, requiring less maintenance and lower utility bills. 

The greener picture
Passive ventilation is one piece of a much larger green construction puzzle. A key component in reducing operation emissions, its impact can be amplified when considered in tandem with other modern, eco-friendly design and building techniques, such as low-energy lighting and material-based approaches such as ‘fabric first’.

Smartly controlled passive ventilation can enhance material-based thermal performance, working with a structure’s thermal mass for efficient and effective cooling throughout the day. If it’s designed and precisely controlled according to fluctuating indoor and outdoor conditions, it works year-round whatever the weather or climate to reduce heat loads in the building from people, lights, and computers, among other equipment. 

Going a step further, organisations can consider eco-friendly power sources for their HVAC, passive or otherwise, such as the latest PV solar panels. These are reliable energy generators, capable of taking full advantage of the sun when it shines, potentially producing enough clean energy to power smart-controlled ventilation systems and deliver a comfortable interior with freely circulating, high quality air. 

Let’s go retro
We’re likely to see passive ventilation systems become the norm in new builds, as opposed to the exception. While many commercial buildings may require re-engineering, retrofitting passive ventilation is relatively low impact depending on the windows and vents already present. Even where new windows are needed, the impact is low compared to installing a whole mechanical system.

Facilities managers and end users need to understand the benefits of and feel empowered to engage with new ventilation strategies. While they may be carbon intensive, many of the most popular HVAC systems are what people know and are comfortable with. It’s now up to UK Government, working alongside architects and contractors, to step up and develop a strategy to instigate and deliver a green transformation of our work spaces. Research organisations dedicated to indoor climate and the built environment also have a key role to play, shedding light on the latest relevant data and findings to instigate change.

A business is its people. The real benefit of great air quality is a happier, healthier, more productive workforce and a better protected natural environment, making this process worthwhile. Organisations which take the necessary next steps will reap the rewards. 

Erik Boyter is CEO of WindowMaster