Sustainable design has become one of the most commonly coined phrases in the design industry in recent years.
The discussion and implementation of sustainable design is a reaction to global environmental crises, rapid growth of economic activity and human population, depletion of natural resources, damage to ecosystems, and loss of biodiversity.
However, does the consumer really understand what constitutes sustainable design?
Many believe that achieving the mandatory energy efficiency provisions of the building code and installing solar panels on the roof, qualify as sustainable design. But it is so much more than this.
To truly embrace sustainability, we must begin by altering the occupant’s behaviour.
Designers continually battle with consumer requests, such as why large west facing windows are not a good idea and why a more efficient air conditioner does not negate the westerly window.
The objective of sustainable design in the past has been to simply improve the efficiency of the built environment. However, this approach does not solve the problem of global warming. The basic dilemmas include the increasing complexity of efficiency improvements, the difficulty of implementing new technologies in societies built around old ones, and that the scale of the use of resource is growing and not stabilising.
In today’s climate, the main objective of sustainable design is to reduce, or completely avoid, depletion of critical resources such as energy, water, and raw materials including coal, gases and the like. It also prevents environmental degradation caused by developments and infrastructure throughout their life cycle; and creates built environments that are liveable, comfortable, safe, and productive.
Buildings use resources (energy, water, raw materials), generate waste (occupant, construction and demolition), and emit potentially harmful atmospheric emissions. Building owners, designers, and builders face a unique challenge to meet demands for new and retrofitting existing buildings that are accessible, secure, healthy, and productive while minimising any negative impacts on society, the environment, and the economy. Ideally, building designs should result in net-positive benefits across all three areas.
In addition to including sustainability concepts in new construction, sustainable design advocates commonly encourage retrofitting existing buildings rather than building anew. Retrofitting an existing building can often be more cost-effective than starting from scratch. Designing major renovations and retrofits for existing buildings to include sustainable design attributes reduces operation costs and environmental impact, and can increase building resiliency while minimising land fill. This is referred to as adaptability, and allows multiple uses for multiple occupants, prolonging the life of the building.
The embodied energy of the existing building, a term expressing the cost of resources in both human labour and materials consumed during the building's construction and use, is squandered when the building is allowed to decay or be demolished.
Sustainable architecture attempts to reduce the collective environmental impacts during the production of building components, during the construction process, as well as during the life cycle of the building (through heating, electricity use, carpet cleaning and so on), decreasing the embodied energy in the building.
The common principles of sustainable design are:
Creating sustainable buildings starts with site selection, including consideration of the reuse or rehabilitation of existing buildings. Site selection should consider the location, orientation, and landscaping of a building, as well as how it impacts on local ecosystems, transportation methods, and energy use. It is important to incorporate smart growth principles into the project development process, regardless of the scale of the building or development.
Whether designing a new building or retrofitting an existing building, site design must integrate with sustainable design to achieve a successful outcome. The site of a sustainable building should reduce, control, and/or treat storm water runoff for reuse. Where possible, it should strive to support native vegetation of the region in the landscape design without any impact on local ecosystems.
Indoor environmental quality
The indoor environmental quality of a building has a significant impact on occupant health, comfort, and productivity. Among other attributes, a sustainable building maximises daylight, has appropriate ventilation and moisture control, optimises acoustic performance, and avoids the use of materials with high-VOC emissions. Principles of indoor environmental quality also emphasise occupant control over systems such as lighting and temperature.
As demand on the world's fossil fuel resources continues to increase and the impacts of global climate change become more evident, it is essential to find solutions to reduce energy load, increase efficiency, and maximise the use of renewable energy sources in development. Improving the energy performance of existing buildings is an important factor in increasing our energy independence. Design practice needs to emphasise efficiency of heating and cooling systems, alternative energy sources such as solar hot water, appropriate building siting, reused or recycled building materials, and on-site power generation such as solar technology, ground source heat pumps and wind power.
In many parts of the world, fresh water is an increasingly scarce resource. A sustainable building should use water efficiently, and reuse or recycle water for on-site use where possible. The effort to bring drinkable water to households consumes enormous energy resources in pumping, transport and treatment. Therefore, rainwater harvesting for gardening and washing, and on-site waste management such as green roofs that filter and control storm water runoff are excellent sustainability options.
Optimise building space and material use
While the world population continues to grow (to over 9 billion by 2050), natural resource use will continue to increase and the demand for additional goods and services will continue to stress available resources. It is critical to achieve an integrated and intelligent use of materials that maximises their value, prevents pollution, and conserves resources.
A sustainable building is designed and operated to use and reuse materials in the most productive and sustainable way across its entire life cycle, and materials are selected for their adaptability for for reuse. The materials used in a sustainable building minimise life cycle environmental impacts such as global warming, reduction in resources, and human toxicity. Environmentally preferable materials have a reduced effect on human health and the environment and contribute to improved worker safety and health, reduced liabilities, reduced disposal costs, and achievement of environmental goals.
Designing buildings to last
Building resiliency is the capacity of a building to continue to function and operate under extreme conditions, such as (but not limited to) extreme temperatures, sea level rise, and natural disasters. As the built environment faces the impending effects of global climate change, building owners, designers, and builders can design buildings to optimise building resiliency.
Buildings should also be designed and built with a lifespan to far exceed the expected life span of its occupants to minimise demolition and waste and avoiding rebuilding every 20 to 30 years to suit the needs of the new occupants.
Consideration should be given to building adaptability and is the capacity of a building to be used for multiple purposes over the life of the building. For example, designing a building with movable walls/partitions allows for different users to change the space. Additionally, using sustainable design allows for a building to adapt to different environments and conditions including flexibility over different occupants and their stages of life. This will in turn prolong the life of the building, decreasing the embodied energy over the multiple uses of the building.
The considerations listed above will prove ineffective unless the occupant’s lifestyle and habits are thoroughly evaluated. To truly embrace the ethos behind sustainable design, both designers and occupants need to consider the embodied energy in material used in the construction and throughout the life cycle of the building, renewable materials must be utilised, and the occupant’s habits and lifestyle practices must be examined and adjusted where required.
Sustainable design must create projects that shift the behaviour of the building’s occupants. This involves striking a dynamic balance between economy and society - to generate long-term relationships between user and the built environment, and to promote respect and mindful treatment of surrounding ecosystems.