There are some organizations to define the sustainability of buildings. For example, world green building council and leadership in energy and environmental design. I think the core values are approximately same, to reduce waste, cost and improve efficiency and sustainability. For each utility part (water, energy, material, etc.), a certain limit was set by those standards. In addition, from the definition of sustainability, we can see that “sustainability means meeting our own needs without compromising the ability of future generations to meet their own needs.” The green building is part of Earth's sustainability (shown in Figure below). After all, the building is nothing more than a habitat for the human being. We can think of the building as a plant, and the plant (a tree, since there are a lot of animals living on tree.) can exchange energy with ecosystems (absorb water, CO2, release heat, oxygen), and provide animal habitat and food. Nowadays, the use of effort, cost, and energy is significant and building construction contributes to a big part of global pollution. In 19 century, we want to build stable, strong, durable, and economical, but we realized that our ecosystems are burdened. From my understanding (think the building as a part of the ecosystem, which can contribute to energy, information, and environmental-friendly exchange).
- We need to consider the building materials, can we use alternative material with low imbedded energy, and pollution? At the same time, the “engineering” properties of the materials are not compromised significantly (losing strength). Like we can build the house with recyclable materials so that the building materials can be recycled at end of its life cycle. We also want to achieve the economical purposes, and we do not want some materials with good green and engineering properties but unaffordable.
- Environmentally-friendly, recyclable, economical, safe building material
- Building inside and outside layout to help building sustainability
- Controlling the energy input. After the building was constructed, we need to consider the daily energy usage (water, electricity, gas, heating, cooling etc.). We can apply sustainable appliances (energy saving appliances) if there are sustainable appliances. More importantly, the building layout design can significantly affect the sustainability and energy saving (zone space can affect the natural light utilization, heating or cooling efficiency). Some ancient building last hundred years but need to use materials to fix it. I believe some modern buildings are also required to maintain. Such a cost needs to be considered.
- Control building energy usage
- Solar, rainwater, sustainable energy to supply the needs.
- Building maintenance, needs to be durable.
- Adaptability
There are a lot of climate zone and geographic differences on Earth, and this is the reason why some ancient buildings are different and they are built for adapting the local climate. Designing the sustainable building also needs to consider the geographic issue.
Overall, I think sustainable buildings mean reducing the cost to build it (both economically and environmentally), and needs from the environment (reducing the utility cost). At the same time, try to meet the building council standard. Most importantly, we need to think out of the box, for example, new building systems, materials, and designs to adapt to the Earth environment.