Net Zero Buildings: The Key Principles in Design & Construction
We hear ‘Net Zero’ in the news often and frequently from the mouths of politicians. Yet how does the term specifically apply to building design?
Firstly, let’s quickly recap what problem Net Zero is trying to solve: Climate Change. The emission of greenhouse gases from human activity is the main driver of climate change on the planet. Greenhouse gases trap heat and make the planet warmer, leading to a slew of potentially catastrophic problems.
Carbon Dioxide (CO2) is only one of the greenhouse gases, which include methane and chlorofluorocarbons. However, it is the primary gas released by human activity and the one that causes the most harm.
In simple terms, Net Zero refers to an offset between the amount of greenhouse gas produced and the amount removed from the atmosphere. It means cutting climate pollution to as close to zero as possible and investing in renewable energy and Carbon Capture Technologies, as well as other strategies which remove greenhouse gases from the atmosphere.
As of 2022, the Australian Government has enshrined in law a commitment to cut greenhouse gas emissions by 43% by 2030, with a target of Net Zero by 2050.
The design and construction industry has a crucial role to play in achieving Net Zero. As we’ve recently discussed on our Thermotalk podcast, 38% of greenhouse gas emissions stem from the global building industry.
Let’s look at the techniques which can be implemented by architects, designers, and builders to achieve Net Zero Buildings.
What exactly is a ‘Net Zero Building’?
A Zero Energy Building (ZEB), also known as a Net Zero Building (NZB), is a building with Net Zero energy consumption, so:[Total Amount of Energy Used Onsite] = [Amount of Renewable Energy Created]
The goal is that less overall greenhouse gas is contributed to the atmosphere during operations than in similar buildings. A Net Zero Building may at times consume non-renewable energy and produce greenhouse gases. However, this is offset by reduced energy consumption and renewable energy.
The development of Net Zero Buildings is now being encouraged by tax breaks and savings on energy costs, making them more economically viable.
The design and construction of Net Zero Buildings.
To optimise efficient energy use, Net Zero Building design usually takes cost-effective steps during construction to reduce energy consumption.
Designers typically incorporate passive design features in the building envelope that will work in tandem with on-site renewable energy assets like solar energy.
Architects and designers now have access to sophisticated 3-D building energy simulation tools that model how a building will perform under a range of conditions, incorporating the planned design. These models consider windows and doors, insulation, air tightness and heating, cooling, and lighting efficiency. This allows them to perform a building life-cycle assessment before construction.
Incorporating high-efficiency, energy-saving features.
Energy-saving design features in the structure are a crucial component of Net Zero Buildings. For example, heating and cooling loads may be lowered by heat pumps, which are around four times as energy efficient as furnaces. Added insulation and high-efficiency windows (such as double or triple-glazed ones) are the key.
Another important area is energy-saving devices and appliances: e.g., skylights for natural light during the day, LED lighting for nighttime which uses 1/3 less power than incandescent lights, passive solar gain in winter and shading in summer and natural ventilation. The devices used will vary depending on the local climate and the position of the building.
Once the energy use has been minimised, it’s possible to generate energy onsite using techniques such as roof-mounted solar panels. Another way Net Zero Buildings harness and reuse energy is from appliances. For example, refrigerator exhausts can be used to heat water servers.
In short, Net Zero Buildings make use of heat energy that conventional buildings may exhaust outside.
What’s the difference between Net Zero Buildings and other terms such as Passive House, Green Building and NABERS?
There are many organisations operating within the sustainable design and construction space, with a lot of different terms in circulation.
Their common goal is decarbonisation, although they may take a different approach to achieve this.
These buildings focus on reducing three key kinds of greenhouse gas emissions:
1) Embodied Emissions. These are emissions during production, construction, maintenance, replacement, and end of life.
2) Operational Emissions: i.e., Impacts from heating/cooling, hot water supply, ventilation, and lighting.
3) Whole-life emissions: or a combined life-cycle approach. This takes into account both embodied and operational emissions.
As discussed on our podcast Thermotalk, different organisations [in the sustainable space approach] the process in various ways. Some only refer to one or the other. Some allow options. Some, like Passive House, focus on whole-life emissions, and complete environmental ownership.
In this design approach, the house is passive in that the building envelope does most of the work to maintain the temperature, without active input. It achieves thermal comfort with minimal heating and cooling by harnessing insulation, airtight sealing, optimised window and door design, ventilation and heat recovery.
The Green Building Council focuses on Embodied Carbon. This means measuring emissions during production, construction, maintenance, replacement, and end of life.
“All organisations are heading the same way. Sooner or later, they will take a combined life-cycle approach,” says Michael from Thermotalk.
In many ways, it’s an exciting time in Net Zero Building design. “Carbon Capture Technology or CCT is a whole new world. Machines are sucking out carbon from air. They are storing it deep underground or converting it into material. In the future, we will create building materials from Carbon Capture Technology.”
How do windows and doors assist in achieving a Net Zero Building?
Windows and doors form part of a building’s ‘envelope’. A building envelope is the exterior or shell of a building.
As outlined above, to achieve Net Zero Buildings, optimising the building envelope is a primary focus. For instance: lighting, the walls, roof, glazing, heating, ventilation, air conditioning, renewables, windows, and doors.
The building envelope achieves most of a building’s energy savings, by resisting heat flow and improving performance.
Windows and doors make up about 20% of the building envelope. As a window and door manufacturer, Thermotek can help decarbonise Australian buildings.
How Thermotek windows and doors help achieve Net Zero Buildings
Thermotek sustainable windows are engineered in Germany and manufactured in Australia, crafted for outstanding thermal performance and energy efficiency.
The uPVC used has high thermal insulation properties, while the IGUs (insulated glass units) use standard Low-E glazing with argon gas.
The window frames consist of various fusion welded air chambers. These give a superior seal which increases insulation, and the dual TPE (thermoplastic elastomer) seals further enhance thermal performance.
The gap between the two panes in Thermotek windows is the main source of insulation, which slows down thermal transfer by conduction. The systems slow down air circulation to reduce the amount of heat lost in winter and gained in summer.
In winter, when cold air hits the first windowpane, it doesn’t reach the inside environment. Instead, it reaches the gas or air between the panes. By the time it hits the second pane, it is no longer freezing cold.
Thermotek systems help achieve Net Zero Buildings by keeping the temperature stable and significantly reducing the amount of energy needed from heating and cooling systems.
Thermotek’s smart-slide doors also have outstanding capabilities for heat insulation, statics, and sealing.
They make a building airtight against air, wind, and rain, with an innovative locking mechanism and high-quality sealing with no brushes. The window-door systems also require reduced maintenance due to their stable, concealed hardware.
Thermotek windows and doors are a cost-effective strategy to produce a high-efficiency building envelope, thus helping you achieve Net Zero.
Net Zero Buildings are a combination of efficiencies and renewable energy
In addition to optimised thermal performance in the building envelope, the key to Net Zero Building design is also using alternative sources of energy. This might include solar, wind, geothermal, and biomass. Smart appliances and low-energy consumption technology are other methods.
Collecting, storing, and distributing energy from the sun is what passive solar design involves, which when combined with a high-performance building envelope will reduce heat transfer in both directions.
Net Zero is the future. Like to know more about how thermal optimisation can help you achieve a Net Zero Building design? Listen to ThermoTalk, our podcast about smart, sustainable living, hosted by Sasha and Michael.
Explore the Thermotek range of windows and doors today.