Net-zero-energy building

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.

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.

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.

Learn how society can benefit from the renovation of buildings