Zero Energy


The Energy performance of buildings directive recast (EPBD recast)
came into force on 9 July 2010. Member States had to adopt and publish,
by 9 July 2012 at the latest, the laws, regulations and administrative
provisions necessary to comply with most of the articles.

Member States shall ensure that by 31 December 2020, all new buildings are nearly zero- energy buildings; and after 31 December 2018, new buildings occupied and owned by public authorities are nearly zero-energy buildings.

EPBD recast requires nearly nZEB buildings, but since it does not give minimum or maximum harmonized requirements as well as details of energy performance calculation framework, it will be up to the Member States to define what these for them
exactly constitute.

About nZEB nZEB is typically a grid connected building with very high energy performance. nZEB balances its primary energy use so that the primary energy feed-in to the grid or other energy network equals to the primary energy delivered to nZEB from energy networks.

Annual balance of 0 kWh/(m² a) primary energy use typically leads to the situation where significant amount of the on-site energy generation will be exchanged with the grid. Therefore nZEB produces energy when conditions are suitable, and uses delivered energy during rest of the time.

When architects and clients are considering an nZEB project, the following 6 areas should be actively considered
in the design process:

  1. Design and objective - decide on which nZEB definition the project will be based around. For example, equivalent energy, equivalent money or equivalent emissions – and base the design around the appropriate criteria;
  2. Consider the local/regional climate and weather conditions and seasonal patterns - nZEB designs are particularly sensitive to such variables, and what makes sense in a northern European or Scandinavian country, wont in a Mediterranean country. This will also impact on the project design and objective;
  3. Passive strategies – these will vary from location to location and be influenced by local weather and climate. Projects in colder northern climates might focus on insulation and heat recovery, whilst projects in warmer more southern European climates may tend to focus on shading and natural ventilation;
  4. Energy efficiency – this will commence with the minimum performance standards required by local/regional/national legislation or regulations, and cover everything from insulation, airtightness, ventilation, air quality, conservation of energy etc.;
  5. Renewable Energy Systems (RES) – consideration must be given to integrating RES into the nZEB design from the first concept sketches, for example building orientation will help maximize sunlight for PV systems and solar hot water;
  6. Technology – by their very nature nZEB projects will require technology to maximize the benefits of any given design and objective, so it’s important to utilize the most effective technology available at the time of specification.

And finally, except the available technology, very important factor in sustainability of nZEB is user/customer behavior.