Nearly zero-energy buildings guidelines (nZEB)

Guidelines for nearly zero-energy buildings have been developed in order to ensure that both the general public and professional experts are informed about the design and construction of nearly zero-energy buildings. The guidelines are intended for investors who start building their buildings after 31 December 2019, but also for experts who will participate in the designing and construction process.
 
It is estimated that buildings account for approximately 40% of total energy consumption in the European Union and the aim is to reduce energy consumption in the buildings sector. Compliance with building requirements for nearly zero-energy buildings is prescribed under Directive 2010/31/EU of the European Parliament and of the Council of 19 May 2010 on the energy performance of buildings (recast), and the provisions of this Directive have been transposed into the legislative framework of the Republic of Croatia prescribed by Buiding Act (Official Gazette 153/13 - Provisional Translation, 20/17, 39/19, 125/19) and Technical regulation on energy economy and heat retention in buildings (Official Gazette 128/2015, 70/2018, 73/2018, 86/2018 and 102/2020).
 
Nearly zero-energy buildings (nZEB) have a very high energy performance and this nearly zero or very low amount of energy required should be covered to a very significant extent by energy from renewable sources, including energy from renewable sources produced on-site or nearby.

All new buildings for which the application for issuing the building permit is submitted after 31 December 2019 have to meet the requirements for nZEB, and public buildings owned by public authorities and used for performing their activities, were already supposed to be nearly zero-energy buildings, if the building permit application was submitted after 31 December 2017.
- Exemption: buildings for which an application for a location or building permit was submitted before 31 December 2019 do not need to meet nZEB requirements.
- Exemption: buildings used by public authorities as owners if the application for a location or building permit was submitted before 31 December 2017 do not need to meet the nZEB requirements.

According toTechnical Regulation in the Building's energy performance register, which is a separate document mandatorily attached to the main project (when the main project is drafted in the part relating to rational energy use and thermal protection), "nZEB" should be written if the energy performance of a building and the share of renewable energy sources meet the requirements for nearly zero energy buildings.

Since requirements for nearly zero energy buildings are prescribed in Technical Regulation only for new buildings, almost zero energy buildings (nZEB) in addition to the requirements of this technical Regulation must fulfil other basic requirements, i.e. regulations relating to new buildings.

It is advisable to design buildings in such a way that their amount of energy needed is as low as possible. There are no universal solutions to achieve the nZEB standard. A coordinated integrated approach of all professions involved in building design is required (the completeness and mutual alignment of designs of the building architecture, building physics, thermal and technical systems and electrical installations), from the concept and conceptual design of the building to the detailed design and professional and carefully controlled execution. A highly optimized energy concept enables low energy consumption and renewable energy use with lower investment costs and results in a cost-optimal solution that meets the nZEB standard.
 
For nearly zero-energy buildings it is mandatory to perform the blower door test, which is carried out according to the prescribed standard before the technical inspection of the building. For residential buildings that have more than one apartment, the air-tightness requirement shall be fulfilled for each apartment within the building.
 
Energy certificates of new buildings are issued on the basis of data from the main design in relation to energy economy and heat retention in buildings, a written statement of the contractor on the works completed and the requirements for the maintenance of the building, regular visual inspection of the building and the final report of the supervising engineer if there was an obligation for its preparation. The nZEB mark is entered in the energy performance certificate of a building or a particular part thereof. The energy certificate is produced by electronic means and printed exclusively through the Energy Certification Information System (IEC).
 
The guidelines can be downloaded at the links below (Croatian only):