Table of contents
- Obligation to refurbish in accordance with the Building Energy Act
- Requirements for existing buildings
- Requirements for technical building systems
- Building optimization
- Savings potential in buildings
- Thermal insulation
- Efficient building technology
- Building digitization
- Digitization in existing buildings
- Advantages of energy optimization of buildings
- State support
Obligation to refurbish in accordance with the Building Energy Act
Energy consumption in German buildings is too high! The German government has therefore set itself the goal of reducing heating requirements in buildings by 80% by 2050. If this goal is to be achieved, there is no way around the mass refurbishment of existing buildings. Therefore, the Building Energy Act (GEG) has been in force since November 1, 2020. This leads requirements for the energy quality of buildings. It also obligates the declaration of the building-specificCO2 footprint in the energy certificate and prescribes the purchase of renewable energies for public buildings. The requirements of the GEG for buildings are regularly renewed and tightened. Here it is worthwhile to introduce efficiency measures at an early stage. Compliance is verified by the chimney sweep and the local building department.
Requirements for existing buildings
Minimum standards must be met
When renovating the exterior of a building, minimum thermal insulation standards apply, which are defined in Annex 7 of the GEG. Alternatively, the requirements are also considered to be met if both the annual primary energy demand and the heat transfer coefficient of a reference building defined in the GEG are not exceeded by more than 40%.
Minimum thermal protection
The GEG prescribes a minimum thermal insulation according to DIN 4108-2:2013-02. If this is not met, the floor slabs or roof must be subsequently insulated so that a maximum heat transfer coefficient of 0.24 W/m2Kis ensured.
Energy certificate
When selling or renting the building, an energy certificate must be given to the buyer or tenant. In highly frequented buildings, the energy certificate must also be displayed in a clearly visible manner. This applies to official buildings with a usable floor area of 250m2 or more and to other buildings with a usable floor area of 500 m².
Renewable energies
Public buildings should act as role models for climate protection. Therefore, it is true that the energy demand after renovation must be partially covered by renewable energy. Alternatively, the requirement can be met through the use of waste heat, a CHP plant, the purchase of district heating or cooling, or through measures to save energy.
Requirements for technical building systems
Replacement of oil and gas heating systems
Old oil or gas heating systems with an output of 4 to 400 kW must be replaced if they were installed before 1991.
Automatic controls for central heating systems
Since October 2021, central heating systems must be able to automatically control heat supply and the switching on and off of electric drives depending on the outside temperature and time.
Automatic controls of room temperatures
Heating systems must have automated control of individual room temperatures. Group regulations are permissible for rooms of the same type and use.
Insulation on pipes
Freely accessible heating and hot water pipes and their fittings must be insulated in unheated rooms.
Controls for air conditioning and ventilation systems
In newly installed air conditioning systems with a cooling demand of more than 12 kW and in room air conditioning systems with a supply air volume flow of more than 4000m3/h applies:
- the specific power of fans is limited according to DIN EN 16798-3.
- automatic control of humidification and dehumidification of the air as well as separately adjustable setpoints become mandatory
- If the supply air volume flow of the system to be installed is greater than 9m3/h per square meter, automatic control of the volume flows must be possible.
- In addition, a heat recovery device is mandatory where feasible.
Circulating pumps
Newly installed circulation pumps with a rated output of more than 25 kW in the heating circuit of a central heating system must be automatically adaptable to the delivery requirement in 3 performance levels
Building optimization
The basic principle in the energy optimization of existing buildings is to reduce energy consumption through efficiency measures. In times of rising energy prices, energy savings are clearly reflected in operating costs. Investments in energy optimization in buildings therefore usually pay off after a very short time. In addition to energy cost savings, optimizing energy consumption also improves their company’scarbon footprint, making a valuable contribution to climate protection. There are many approaches to reducing energy consumption.
Savings potential in buildings
Energy consumption in German buildings is too high! The German government has therefore set itself the goal of reducing heating requirements in buildings by 80% by 2050. If this goal is to be achieved, there is no way around the mass refurbishment of existing buildings. Therefore, the Building Energy Act (GEG) has been in force since November 1, 2020. This leads requirements for the energy quality of buildings. It also obligates the declaration of the building-specificCO2 footprint in the energy certificate and prescribes the purchase of renewable energies for public buildings. The requirements of the GEG for buildings are regularly renewed and tightened. Here it is worthwhile to introduce efficiency measures at an early stage. Compliance is verified by the chimney sweep and the local building department.
Thermal insulation
Retrofitting buildings with insulation reduces energy losses caused by heating heat or air-conditioning cold being lost to the environment through the building envelope. Especially in older buildings, large amounts of energy are lost through the exterior walls and roof. Thermal insulation can significantly reduce heat transfer and thus energy consumption. Worthwhile is the insulation of the facade (from the outside or inside) and the insulation of the top floor ceilings or the roof. One way of identifying weak points in the building envelope is thermography, for example with the aid of a thermal imaging camera. Insulation of plant components and pipes carrying hot water can also help to reduce energy consumption and increase the energy efficiency of building services.
Efficient building technology
The installation of more efficient technical systems or the replacement of individual components in building technology can in some cases result in major efficiency improvements. The following points can be worthwhile.
Building digitization
The simplest form of implementing energy optimization in existing buildings is usually digitization. This enables demand-driven control of energy flows and helps identify inefficiencies and further savings potential. For this purpose, sensors are installed that collect valuable data about the building, environmental influences and the building technology. Automation technology controls the building technology according to demand and reduces energy consumption. Energy monitoring also enables the identification of inefficiencies and potential for improvement.
Digitization in existing buildings
Digitization is the future! And not just for new buildings. Especially in existing buildings, the realizable savings through intelligent building automation are enormous. But what does digitization of buildings mean? Digitized buildings are also referred to as smart buildings. This refers to the collection of a wide range of information from all areas of the building and the automated control of actuators such as ventilation or heating systems that this enables. This makes it possible to use energy in a targeted manner and only where it is needed. Another advantage of building digitization is energy monitoring. Information about the building and the technology installed in it can be read out in software and displayed in a visualized form, giving the person in charge good transparency about the building data and the use of the technology. This enables holistic energy management.
In the past, retrofitting existing buildings involved a great deal of effort, as the installed technology had to be wired in a very complex manner. Thanks to the radio-based LoRaWAN technology, the connection of sensors and actuators to the building technology can be implemented quickly and cost-effectively even in existing buildings – without drilling holes and pulling cables.
Advantages of energy optimization of buildings
State support
When optimizing the energy efficiency of buildings, you will receive financial support from the state for many measures, so that the investment pays off even faster. Subsidies are granted by the Federal Office of Economics and Export (BAFA), and the Kreditanstalt für Wiederaufbau (KFW) grants loans with a repayment subsidy. The following measures are eligible.
Heating optimization
- Hydraulic balancing incl. Setting the heating curve
- Replacing heating pumps and adjusting the flow temperature and pump capacity
- Measures for lowering the return temperature in building networks
- Heat pump optimization
- Insulation of pipelines
- Installation of panel heaters, low-temperature radiators and heat accumulators
- Measurement and control technology
Plant engineering
- Ventilation systems with heat/cold recovery
- Building automation with measurement and control technology
- Plants for room cooling
- Efficient lighting systems
- Plants for heat generation from renewable energies or CHP plants
- Measures for heating optimization
Thermal insulation
- Insulation of the building envelope and renewal or preparation of curtain walls
- Replacement of windows, external doors and gates
- Installation and replacement of shading devices
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