Net-zero buildings are essential to averting the climate crisis. Given that the building sector is responsible for 40% of global emissions, it’s clear to see how much of a difference net-zero construction can really make. Under the targets of the Paris Agreement, billions of buildings globally will need to be net-zero by 2050 if the sector is going to achieve its targets. So, what does that actually mean and can a building really be net-zero?
Defining a net-zero building
When it comes to what constitutes a net-zero building this is generally defined as a building that makes its own energy through renewable sources that don’t generate emissions. The building will, effectively, create as much energy as it consumes, which renders it ‘net-zero.’ In order to achieve this, buildings can combine generating their own energy and using carbon offset. The percentage of carbon offset that is acceptable in order for a building to still count as net-zero will depend on local law.
How does a building become net-zero?
These are some of the key factors that need to be taken into account in the design of an energy-efficient building.
- Location and orientation. Location will include integrating the influence of factors such as climate, temperature, and rain patterns. Orientation is how the building can be positioned to take maximum advantage of the physical attributes of its situation. For example, south-facing buildings are a great place to optimise the use of solar panels while orienting a building to take into account natural light through window arrangement, skylights, etc can significantly reduce energy consumption.
- Design. The way a building is designed will have a big impact on how energy efficient it is capable of being. Passive strategies involve minimising energy consumption and maximising performance and can be vital here. They include high-efficiency appliances, low-energy HVAC systems, insulation, and air sealing.
- Integration of renewables. No building can be truly net-zero without integrating renewables. The design of any construction will need to take into account what is likely to be the best type of renewables to invest in. Active strategies can help to minimise energy consumption during the process of building, as well as afterwards. These include the use of wind power or photovoltaics, as well as hydroelectric or geothermal power, biomass energy or solar power. Which of these is going to be the most appropriate will depend on which renewable energy sources are likely to be the most relevant.
What about retrofitting existing buildings?
It is possible to add new technologies to existing structures to help reduce energy consumption and emissions. This process is less expensive than building new and also more environmentally sound. Two strategies that are particularly effective are building reskinning (effectively, insulating building exteriors) and packaged mechanics (grouping together mechanical components into a single unit for ease of installation and control).
Yes, it is possible for a building to be net-zero – or to be retrofitted in order to take it closer to this target. As we move towards key deadlines for climate change it’s going to become increasingly vital for all construction projects to be able to achieve this.
