The DIN V 18599 is the central standard for the Energy assessment of buildings in Germany. It is used to calculate the energy requirements of residential and non-residential buildings and, since January 1, 2024, has been the Mandatory basis for energy assessment in accordance with the Building Energy Act (GEG). This replaces previous calculation methods and ensures a uniform, holistic and detailed analysis of energy consumption.
The standard covers all relevant areas such as heating, cooling, ventilation, domestic hot water and lighting and also takes into account electricity-producing systems such as photovoltaics. This makes it an important tool for architects, engineers and energy consultants in the development of sustainable buildings, energy-efficient building concepts. DIN V 18599 was first published in 2005 and has since undergone several revisions in order to adapt it to technical progress and new legal requirements.
It serves as a reference for the Energy Saving Ordinance (EnEV), the GEG and contributes significantly to the implementation of the EU Buildings Directive to the overall energy efficiency. DIN V 18599 has fundamentally changed the way in which the energy performance of buildings is assessed and enables a detailed comparison of different building concepts. Despite its complexity, the standard is an essential tool for reducing energy consumption and achieving climate protection targets.
Structure and organization of DIN V 18599
DIN V 18599 is a comprehensive standard consisting of a total of 13 parts. Each part deals with specific aspects of the energy assessment of buildings and together form a complex but holistic system for calculating energy requirements. The individual parts are closely interlinked and build on each other.
Part 1 forms the basis by setting out general calculation methods, definitions of terms and the zoning of buildings. The following Parts 2 to 4 deal with the calculation of the useful energy demand for various applications such as heating, cooling, ventilation and lighting. Parts 5 to 8 deal with the conversion of useful energy into final energy for various technical systems and Part 9 "Electricity-producing installations". Part 10 deals with conditions of use, climate data and building automation.
Holistic approach of DIN V 18599
DIN V 18599 is characterized by an integrative approach that takes into account the interactions between the building envelope, use and system technology.
The building as an overall system
The standard considers buildings as a unit consisting of three main components:
- Building envelope: Influence of the thermal quality of walls, windows, roof and floor.
- Utilization: Occupancy times, internal heat loads and user behavior.
- Plant engineering: Heating, cooling, ventilation, lighting and hot water systems.
This approach enables a realistic assessment of energy requirements by, for example, taking into account the influence of insulation on heating and cooling requirements or the use of modern hall heating systems taken into account.
Interactions between energy flows
DIN V 18599 goes beyond the mere addition of consumption and integrates it:
- Heat gains/losses: Influence of internal and solar heat gains.
- Energy recovery: Utilization of waste heat and heat recovery systems.
- Temporal aspects: Consideration of fluctuations in energy demand and supply, particularly in the case of renewable energies.
- Building automation: Influence of control and regulation systems on efficiency.
Thanks to this comprehensive assessment approach, the standard enables a more precise analysis and supports planners in the development of optimized, energy-efficient building concepts.
Calculation methodology & areas of application
DIN V 18599 enables a holistic energy assessment of buildings using a multi-stage calculation method. It comprises the useful energy demand (energy actually required for heating, cooling or lighting), the final energy demand (including losses during conversion and distribution) and the primary energy demand (total energy including extraction and transportation).
A central concept is zoning, in which buildings are divided into areas with similar usage conditions. The calculations are usually carried out using a monthly balance method, but can also be carried out on an hourly basis if required.
The standard is used in the preparation of energy performance certificates, the planning of energy-efficient buildings and the assessment of existing buildings. It helps to analyze the current status, identify weak points and derive optimization measures.
Photovoltaic systems in DIN V 18599
DIN V 18599 considers photovoltaic systems (PV systems) as a central component of energy-efficient building design and systematically integrates them into the overall energy balance. The standard does not consider PV systems in isolation, but as part of the overall energy system. Accordingly, they significantly reduce the primary energy demand by:
- Own use of PV electricityThe proportion consumed directly in the building reduces the final energy demand from the grid and increases the energy efficiency. Photovoltaic self-consumption.
- Better energy efficiency classesBuildings with PV systems often achieve better energy performance certificates, which makes renting or selling them more attractive.
- Grid feed-inSurplus electricity is credited to the balance sheet and improves the building's primary energy balance.
- System interactionsThe standard covers how PV electricity supports other systems (e.g. heat pumps or ventilation systems) and thus creates synergies.
- Sustainability and CO₂ reductionThe use of renewable energies significantly improves a building's carbon footprint.
Calculation rules
The standard defines specific calculation rules that ensure that the contribution of PV systems to the building's energy supply is assessed in a realistic and standardized manner. For example, the monthly electricity yield is determined on the basis of the average global radiation of the Potsdam reference climate zone in order to obtain comparable results regardless of the specific location of the building. Standard values from DIN V 18599-9 are used to calculate the nominal output, which include the Efficiency of solar cells (monocrystalline, polycrystalline or thin-film).
Challenges
However, these rather rigid principles for planning and balancing also present challenges. For example, modern PV technologies with high efficiencies are not always accurately captured by the standard's blanket default values. Similarly, the defined reference climate zone Regional differences in yield potential, for example in particularly sunny areas. Another aspect is the Area-based calculation methodwhich requires an exact measurement of the module surface - a time-consuming process, especially for complex roof structures.
Despite these limitations, DIN V 18599 provides an initial basis for good planning of a PV system in order to fulfill legal requirements such as the GEG and Funding opportunities optimally. However, the latest module types, storage systems and building energy management systems must be taken into account in the further development of the standard.
Changes & continuous processes
For these reasons, DIN V 18599 is continuously revised, as technical progress and legal requirements are constantly changing. The latest version introduces important innovations, including a More precise calculation and accounting methods renewable energies, updated primary energy factors, an extended assessment of building automation and improved calculation methods for non-residential buildings.
Future developments are expected to include greater integration of storage technologies, better linking of the electricity, heating and mobility sectors and the inclusion of life cycle analyses. The focus will also be on adapting to dynamic energy systems and making the standard more user-friendly. These further developments are intended to further strengthen DIN V 18599 as a central instrument for energy-efficient building planning.
Application examples of DIN V 18599
The practical application of DIN V 18599 in the commercial and industrial sector offers particular challenges and opportunities that differ significantly from those in residential construction. A striking example of this is the energy assessment of a modern production hall of a medium-sized mechanical engineering company. In this project, the complex zoning posed a central challenge: The hall included areas for production with different temperature requirements, storage areas, offices and a showroom. Each of these zones had specific usage profiles and energy requirements that had to be taken into account individually in the calculation in accordance with DIN V 18599.
Another instructive case study is the refurbishment of a large logistics center. The focus here was on optimizing the lighting and air conditioning of the extensive warehouses. The application of DIN V 18599 enabled a detailed analysis of the energy requirements for various refurbishment scenarios and hall zones. It became clear how the use of LED lighting in combination with intelligent control systems and the installation of an efficient ventilation system with heat recovery could significantly reduce energy requirements.
In a third case, the standard was applied to the planning of a new technology center for an automotive supplier. Here, the integration of process heat from production into the building energy concept posed a particular challenge. DIN V 18599 provided a framework for quantifying the synergies between production processes and building energy requirements and taking them into account in the overall balance.
Early integration of DIN V 18599 as a success factor
The application of DIN V 18599 in the commercial and industrial sector poses particular challenges, as it has to take into account a variety of types of use, production processes and special technical systems. The recording of process energy in particular requires close cooperation between energy consultants, technicians and production planners. The integration of combined heat and power and large-scale PV systems also requires precise application of the standard.
A key success factor is the early involvement of all relevant stakeholders in order to optimally incorporate operational requirements into the energy assessment. Sensitivity analyses also help to identify optimization potential. Despite its complexity, the standard provides a valuable basis for energy-efficient and economical energy concepts.
Conclusion
DIN V 18599 is a central tool for the energy assessment of buildings. It enables precise calculation of energy requirements and promotes the integration of renewable energies into modern building concepts. It offers great opportunities, particularly in the commercial and industrial sector, but also places high demands on planners and consultants. Despite its complexity, the standard creates a reliable basis for future-oriented and economical energy solutions. As the standard continues to evolve, it will continue to play a key role in implementing the energy transition in the building sector.