Many of the large cities around the world have committed to becoming carbon-neutral by 2050. To achieve this ambitious goal, city governments, property investors, and homeowners will need to make smarter decisions when building new or renovating existing buildings. Net-zero buildings use less energy, provide comfortable indoor climates, and helps the world’s cities become more sustainable for future generations.

Net zero energy buildings is often connected to building new, but did you know that renovating is also a feasible and cost-efficient way to achieve sustainable and energy efficient buildings? In this article we’ll cover the basic of net zero energy buildings and how it can be achieved by renovating or building new.

What is a net-zero-energy building?

A net-zero-energy building (or NZE building for short) has a very high energy performance rating. By reducing the total amount of energy consumed to near zero and offsetting remaining energy consumption with renewable sources, a building can be a net-zero-energy consumer. To reduce the energy demand in buildings, highly efficient insulation materials like stone wool can help improve the thermal performance and provide a healthier indoor climate. Getting a building to net-zero-energy is possible with new builds or deep-energy renovation projects.

The ultimate focus needs to be on reducing energy usage significantly, as saving a unit of energy (kWh) is 14 times less carbon-intensive than producing a unit of energy (kWh) using wind and 25 times less carbon-intensive than solar cells. But once you have maximised the building’s thermal performance, by adding renewable sources for energy supply, it is possible to offset the structure’s electricity requirements and become a net-zero-energy user. A net-zero energy building may use more electricity in some periods but feed back into the grid in other months. That’s what is meant by ‘net’ zero; the net sum of energy is zero or below.

How to achieve net-zero-energy buildings today

Making a building net-zero should start with exploiting the immediate environment to understand where energy gains are available. Considering the building orientation, optimising the shading features, or using bio-climatic and biophilic design principles are all aspects that can help improve energy efficiency.

However, achieving the highest level of energy efficiency will depend on using passive barriers in the walls, ceilings, floors, and roofs that maximise the thermal performance of the building. This is especially true when dealing with a renovation project, where changing the buildings orientation is unlikely to be feasible. Instead, renovating for net-zero-energy involves making the most of what you have and that requires the right solutions. Stone wool insulation uses the strengths of stone to increase the energy efficiency of buildings while also improving the indoor comfort and limiting the effects of noise.

ROCKWOOL building insulation comes in a variety of products that can help reduce the energy demand in buildings. With façade panels, insulation slabs, and other solutions suitable for any type of building, improving the thermal performance of any building is possible using ROCKWOOL products.

Making buildings highly-energy efficient to achieve net-zero-energy consumption

Minimising energy use starts with effective thermal insulation. By improving insulation in buildings, owners can ensure they reduce the operating costs while also making their buildings more sustainable and comfortable.

To achieve this, designs should focus on:

  • Insulating from outside climates – The greater the transfer of the outside climate to the indoor environment, the more energy will be required to harmonise the interior space. With superior insulation on the outer walls, roofs, and in the basement, less energy will be required to maintain the indoor temperature.
  • Eliminating thermal bridges – Thermal bridging is when heat moves from one area to another following the easiest path. Stone wool insulation creates a passive barrier that retains heat or cool air and prevents the air from outside affecting the indoor climate.
  • Eliminate air gaps in windows and doors – Anywhere air can escape or enter the building will reduce the overall thermal efficiency. Upgrading the windows and doors while identifying and sealing any air gaps in the construction will reduce the energy demand of the property.

Benefits of net-zero-energy homes and buildings

For design teams or homeowners focusing on energy performance, net-zero design and construction principles provide additional benefits to both the occupants and the environment. Renovating or building for improved energy-efficiency will increase the property value, raise the energy class and provide cost savings. Adding a layer of high-quality insulation to your building will also make it easier to maintain a stable temperature and humidity, making for a healthier and comfier living or working environment.

With energy renovation providing both energy savings and an increase in property value, renovating for energy efficiency makes for quite a good business case. Additionally, the benefits to productivity, learning environment and living spaces are drastic. By using stone wool insulation to achieve energy neutrality, the indoor environment is significantly enhanced as well. In fact, it is estimated that optimising the indoor environment can increase productivity and learning by more than 12 percent. If you want to learn all the benefits of renovation, why not check out our article on this topic.

Learn more about the benefits of renovation

Why we need net-zero-energy buildings

Across the globe, there is a need for more zero-energy building design and construction methods. These buildings use the same principles of conserving energy by any means possible and using renewable energy sources for their own consumption.

With more net-zero-energy buildings, society benefits by:

  • Reducing the carbon emissions required to power homes, residential buildings, or commercial properties.
  • Creating healthy and comfortable buildings that helps reduce health care costs and improves quality of life
  • Making our building stock more resilient through the use of sustainable, passive systems
  • Using energy efficiently making a reliance on renewable energy sources more feasible

Renovating buildings to be carbon or energy neutral has the most significant potential to achieve carbon and energy neutrality in accordance with the goal in the UN Paris agreement. By 2019, there were roughly 57,000 net-zero-energy homes added to the global building stock, but that number will increase exponentially over the next few years. Europe is expected to lead the way, expected to add 223,000 Zero Net Energy (ZNE) homes each year by 2028. Cumulatively, this would increase the NZE building stock to 2.4 million homes across the region due to the EU’s ambitious regulations.

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