Design Guide: 7 Essential Features of a Net Zero Building

Kiribati is home to around 110,000 people. Its economy is based on agriculture and fishing. It is made up of 33 islands located in the Central Pacific. The highest point at the island’s highest point is only 81% above the sea level. This makes Kiribati the most vulnerable country to disappear due to global warming. In recent years, the climate crisis has been hotly debated. Terms such as carbon footprint and greenhouse effect, atmospheric aerosols and many other terms are now commonplace in our vocabulary. Net zero, or net zero emission is another term that is widely used. It can be used to describe buildings in different industries or countries. It basically means that there is no energy balance.

Frick Environmental Center / Bohlin Cywinski Jackson. Image © Alexander Denmarsh

The 2015 Paris Agreement, which was signed by many countries at COP 21, states that the world must reduce its net emissions by the middle century. The World Green Building Council estimates that the sector accounts for 36% global energy consumption, 38% energy-related carbon emissions and 50% resource consumption. This footprint will double by 2060.

Little House Big Shed / David Van Galen Architecture. Image © Lara Swimmer

The definition of net zero energy for buildings is to produce as much energy as possible in one year. If we add carbon, it’s the same. The goal is to absorb or consume all carbon that was produced during construction and operation. This will also cover the energy used. According to WGBC, a net zero-carbon building is one that uses minimal energy and is powered by renewable energy sources.

It’s a simple idea, but it is not easy to implement. This goal can be achieved with concrete actions in the design process, as well as the selection of materials and products. It is possible to reach this goal or even get close to it in new constructions and renovations. Here are 7 things you should consider to help this global goal.

1. Use the concepts of Bioclimatic architecture

New Comédie de Genève Theatre / FRES Architectes. Image © Yves André

It may seem redundant, but using passive and bioclimatic architecture is key to achieving a net zero building. Energy can be saved by designing projects that are sensitive to the climate and context of each location. This allows for the maximum amount of natural light to be used, and a balanced reduction in thermal energy loss. The building can passively benefit from natural resources by using the correct orientation and well-calculated sun protectors.

2. When possible, provide renewable energy on-site

New Munch Museum / Estudio Herreros. Image © Einar Aslaksen

The idea that buildings can get all their energy from renewable sources, both locally available and low-cost, is at the core of this concept. This could be done by using photovoltaic or water heating solar panels. You can also use local wind systems and other renewable energy sources, if you are able. The building can export excess energy to the network, as long as it is calculated annually. This can be offset by the time the building is not producing energy. However, not all buildings have to be power plants. This is where energy efficiency comes into play.

3. Make sure you use efficient lighting and equipment

Goatbarn Lane / Renée del Gaudio. Image © David Lauer Photography

It is difficult to discuss power generation without mentioning energy efficiency of lighting and appliances. It is essential to find a balance between consumption and generation. This means reducing losses and increasing the efficiency of equipment in buildings. This means that you can generate the same amount of energy using fewer natural resources, or get the same service with less energy. High-efficiency equipment like lighting, refrigeration, HVAC and other equipment will help to save electricity.

4. Attention to the building envelope

SoLo House / Perkins&Will. Image © Andrew Latreille

It is important that the building is efficient, not only in terms of generating energy and avoiding harmful sources. It is essential that the envelope be designed to maximize the use of the environment in which it is situated. A house with good thermal insulation will lose less heat to the surrounding environment in cold regions, which can reduce the need for heating. Thermal inertia is a good option for places with high thermal amplitudes. Walls and ceilings can store heat, and then release it as needed. The envelope can be used to cool and ventilate hot areas. It can also reduce the need for artificial cooling. Thermal insulation can prevent the interior from being too hot due to heat entering the envelope. This means that an envelope’s energy efficiency will increase, which in turn will reduce the amount of operational carbon that is released during its use.

5. Invest in doors and windows

SoLo House / Perkins&Will. Image © Andrew Latreille

This is an important component of efficiency and often accounts for a large portion of the building’s cost. Because it provides daylight and connection to the outside, the main purpose of the window is for building occupants’ well-being. This illustrates the trend towards large dimensions and/or high transparency. The window can be used to maximize energy savings and provide comfort in winter and summer. The ideal window will depend on the climate. Combining high insulation (i.e. low Ug value) with increased sun heat gain (high solar value; g value), in cold climates will help to reduce heating energy consumption and reduce cold surface perception. Warm climates, on the other hand, need to manage sunlight heat incomes (lower g value) and have efficient ventilation to reduce indoor temperatures. The combination of modern coated glasses and efficient window frames allows for a compromise between the two.

6. Eliminate fossil fuels

Bohicket House / Habitable Form. Image © Form Photography & Design

A key concept is to reduce fossil fuel use in buildings. RMI states that gas flaring, along with small amounts oil and propane, is responsible for 10% of all US emissions. Only 10 states account for 56%. They are used primarily for heating water, cooking and water. Instead of using oil or gas, choose renewable energy such as wood and biogas. Heat pumps and geothermal power can be used depending on the situation.

7. Take into account embedded carbon

It is important to consider the impact of every element in a project in order to achieve the net-zero goal. Each material’s carbon content refers to the total greenhouse gas emissions from extraction, transport, fabrication, and installation. Concrete, for instance, is a material that releases a lot of carbon during manufacturing, especially cement. However, the addition of wood to a project can reduce the carbon in the building because the material absorbs carbon as the tree grows. Glass, however, is a material that can be recycled very easily, even though it uses large quantities of carbon in manufacturing. To assess the carbon embodied in a building, it is necessary to have access to data on carbon emissions for all materials and processes throughout its lifecycle.

ENET House / Gole GmbH. Image © Damian Poffet

The Environmental Life Cycle Assessment (LCA) is a standard method to assess the environmental impact of buildings. It covers material extraction, product manufacturing, use, and disposal. This analysis can be used to calculate the total environmental impact of a product’s entire supply chain. These results are presented as Environmental Product Declarations (EPD) which manufacturers are required to consider for their products in order to satisfy a growing market demand to have quantified environmental information.

Even though global discussions such as this may seem far from our everyday lives, we can see how small gestures can make an impact. Latent, all involved in the construction industry and even those who are not in it are aware of the impact they have and the power they have to make real changes. Skepticism has given way to despair about a more hostile future. High initial investment in either construction or remodeling can be required to build net-zero buildings. These can be seen as investments in the future of the world, and in its ability to thrive.