Even as our days get hotter, architect Wong Mun Summ, Co-Founder, WOHA Architects, believes we can still enjoy breezier and shadier environments and spaces with cooler designs for our buildings and districts. 

With Singapore getting hotter over time, how can our buildings be designed to create cooler environments?

Mun Summ: One of the key strategies in creating cooler environments is to allow wind to flow through our buildings and districts easily. So, we need to accentuate wind breezes, more than just harness them.  

We have designed the buildings in Punggol Digital District in a way where they are slightly lifted off the ground. This makes the ground more porous and allows a lot more wind to flow through without being blocked. This means that public spaces on the ground floor can also enjoy more natural ventilation. 

School of the Arts. Image: Patrick Bingham-Hall/WOHA.

We also designed the layout of the tower blocks and the in-between spaces at the School of the Arts carefully to not only allow breezes to flow through but to also accelerate the speed. This creates better cross-ventilation in classrooms and lower carbon dioxide level resulting in students being more alert. 

For high-rise buildings, are there effective ways to create good microclimates within? 

Mun Summ: An interesting element which I find effective for high-rise buildings is the vertical void or atrium. For the design of the 150-metre-tall public housing development in Singapore, SkyVille @ Dawson and another 200-metre-tall private housing complex in Bangkok, The Met, we created a vertical breezeway within the blocks.  

A cross section of Skyville@Dawson. Image: WOHA.

When there is no breeze, the difference in temperature between the ground level and a higher level causes the air to move up through the vertical breezeway. This draws air through the units and the air moves up as well, making the apartments feel cool and airy. 

The taller the buildings, the more effective the vertical breezeway is as you need significant height for temperature difference between the ground and the roof for the hot stack effect to work. This is something we should study further for high-rise, high-density cities like Singapore, to understand how to create better microclimates within our buildings. 

Naturally ventilated walkways and spaces in Skyville@Dawson. Image: WOHA.

In your research, “Designing for Biodiversity, the Value of Nature-Centric Design”, you highlighted the importance of quantifying cooling benefits. Why is collecting data important for your design process?

Mun Summ: We collect insights and data after our buildings are completed and occupied to assess the effectiveness of our designs. It allows us to fine-tune our design process and to keep learning and experimenting to find suitable building typologies and solutions to address emerging new challenges. The data and insights we have gathered, especially in the past five to 10 years, have given us greater confidence to develop more evidence-based designs.

It also allows us to deepen our knowledge-sharing and conversations with clients, stakeholders, peers and the larger community of engineers, planners and urban professionals on how to design more climate-sensitive buildings and what more we can do in future. 

With a greater emphasis on more climate-sensitive building designs, what kind of building forms should we have more of?

Mun Summ: I foresee that our buildings will need to provide a lot more shade and shelter. This is especially important because of climate change, with our weather becoming hotter, and it rains more too.

You will notice that the buildings we have designed, like Oasia Hotel Downtown, the School of the Arts and the Pan Pacific Orchard, are quite large and voluminous. This is because we have deliberately included a lot of internal atriums and semi-open atriums with shading within the buildings. 

The Pan Pacific Orchard hotel breaks from the usual tower-on-podium design with its four large sky terraces, which not only serve as sheltered outdoor spaces, but also help mitigate the heat and contribute towards supporting a richer biodiversity in the city. Image: Darren Soh/WOHA.

To provide sufficient shelter and shade from both the sun and rain, I believe at least 50 per cent of our buildings’ surfaces should be shaded in some way. For example, shading can be provided in the form of deep overhangs or having large urban verandas. 

At the district level, planners are safeguarding wind corridors and planning for nodes and areas with cooler environments. What else should we focus on?

Perhaps we can also think about the way we design our public spaces in creating more climate-sensitive community spaces. With our climate getting hotter, how can we design more conducive public spaces of different scales that are comfortable for people to use and relax in? 

Insights from WOHA’s research, “Designing for Biodiversity, the Value of Nature-Centric Design” on Kampung Admiralty, exploring the cooling benefits of buildings with greenery. Image: WOHA/BioSEA. (View high res image)

I am proud of the ground floor covered space that we designed for Kampung Admiralty, an integrated development with housing for seniors. Because it is an important public space, we deliberately designed it to be covered and shaded so that people can gather here, rain or shine.  

Mun Summ: Beyond just reducing our energy consumption, we have learnt that integrating greenery within our buildings has a much bigger impact in creating better microclimates within our buildings and reducing the overall urban heat island effect than we imagine. 

For example, the Oasia Hotel Downtown, because of its living facade with extensive planting, has a much lower surface temperature of about 25 to 30 degrees Celsius, in contrast to buildings made up of mainly glass and steel which can go up to 50 to 55 degrees Celsius. You can feel the cooler ambient temperature when you walk past the building. 

Insights from WOHA’s research, “Designing for Biodiversity, the Value of Nature-Centric Design”, on the simulated performance and benefits of ecosystem services for various key buildings designed by WOHA. Image: WOHA/BioSEA. 

Besides lowering the surface temperature of the façade, the plants help to regulate and filter pollutants from the air. They contribute a lot more oxygen to our environment. In a way, the building is almost performing like a rainforest. If we continue to create more of such green buildings, imagine what they can do for our city collectively in not just replicating nature but helping to regenerate it as well. 

I believe we are only beginning to appreciate the science and potential impact of green buildings on our environments as our understanding of nature’s ecosystem services³  is still new. There is much more for us to learn and discover.  

What more can we do to further encourage more climate-sensitive building designs amongst industry professionals?

Mun Summ: Even with many building advancements today, designing and constructing a building is still a very complex challenge. There are many different facets and details to prioritise. A first step is to actively engage and educate the industry regularly on climate-sensitive designs. 

Wind corridors safeguarded by URA to guide the future Lentor Hills residential development to enhance wind flow through the development. 

We need to facilitate more extensive dialogue on why it is important to have more climate-sensitive building designs, to share clearly the value and impact not just on our environments but on the quality of our lives and for future generations. We need to also build up the relevant knowledge and skill sets in schools and our younger professionals. 

In addition, more effort and resources should be invested in studying and piloting effective and responsible designs, complemented by suitable policies and guidelines to encourage this.

 ¹ The term “urban heat island” (UHI) refers to the degree to which our urban built environment is hotter than neighbouring rural areas. This happens due to the emitting of waste heat from sources such as cars and factories. Buildings also trap considerable heat during the day which then dissipates at night. A range of strategies are being implemented to address this from deploying an island-wide network of climate sensors to plan and design better mitigation measures, to increasing greenery provision in existing built-up areas, planning layouts of new buildings to maximise shade and wind flow and exploring the use of cool materials for buildings.

² Completed in 2019, SDE4 is Singapore’s first new-build net-zero energy building and is a first in Southeast Asia too. One of its key features is a large overhanging roof which hosts more than 1,200 photovoltaic panels to harness solar energy to meet the energy demands of the building. It also has a hybrid cooling system to manage the building’s energy consumption, supplying 100 per cent fresh pre-cooled air, albeit at higher temperatures and humidity levels than in a conventional system, and augments this with an elevated air speed by ceiling fans.

³ Nature’s ecosystem service is any benefit that we can get from nature. This can range from clean air, a reduction in extreme weather, enhancement of our mental and physical well-being, wood for construction, fresh water, tourism, science, education, recycling, flood protection and decomposition of wastes etc.

Thumbnail image: Pan Pacific Orchard; credit: Darren Soh/WOHA.