Heating systems deploy various technologies and methods. In principle, for example, a distinction can be made between centralised systems, e. g. local and district heating systems, heat transfer, distribution and storage, and decentralised heating systems, which consist of a heat generating plant used for one building or even one residential unit (for more information on heating and air-conditioning systems see heat transfer, distribution and storage).

Both renewable energy and conventional heating systems can be used as local heating systems. These include, for example, micro and mini CHP units, condensing boilers or even heat pumps. Solar thermal systems can also be installed to supplement virtually all of these types of heating. These solar thermal systems can be used to heat drinking water or, if larger solar collector panels are installed, to support the heating system in combination with a gas condensing boiler. The most suitable heating system for a building is determined by the construction method and the resulting heat requirements of the building.

Heat pumps are an example of an efficient way to supply heat to well-insulated buildings. The integration of thermal storage systems, known as buffer tanks in the heating system, is another important component of an efficient heating system. The phase change of the heat potential at times of higher consumption means that peak loads can be sufficiently covered and “buffered”, which facilitates consistent and efficient heating.

Energy can also be saved when heat is distributed in the building through pump systems. By switching off the distribution of heat at times of low demand, e. g. at night, unnecessary energy losses are avoided. In order to do so, pumps with a standby mode are needed. The installation of modern thermostat valves, which can record and regulate the temperature precisely, can also be helpful in achieving the required room temperature.

Ventilation systems can ensure a high quality of indoor air and indoor hygiene by means of the automated, regular exchange of air in buildings. Such systems are especially
suitable for well-insulated buildings with a largely airtight building envelope, as a controlled exchange of air is particularly important here, thus establishing the conditions
for the efficient operation of the ventilation system.

Modern ventilation systems with installed heat recovery and filter technology can deliver potential energy savings of up to 20 percent.

Air-conditioning measures are needed to obtain a room temperature below the outdoor temperature. The most energy can be saved through external sun protection,
which reduces the absorption of heat through radiation and prevents the generation of thermal loads in the first place (these must be otherwise regulated with the use of
energy). If it is not possible to use sun protection or if it is not sufficient to meet cooling requirements, the use of electrically operated air-conditioning systems may be necessary.

The energy consumed by lighting in buildings can be reduced in two ways: energy-efficient lighting systems and needs-based lighting control. Total energy savings of up to 80 percent in the area of lighting can be obtained in this way.

The use of incandescent lamps should be avoided. Halogen lamps are a particular type of incandescent lamp that can achieve energy savings of around 30 percent compared to
conventional incandescent light bulbs. Compact fluorescent lamps, commonly known as energy-saving lamps, can achieve electricity savings of up to 80 percent. However,
the technology used in these lamps means that they have a longer warm-up time before they reach full brightness. This does not happen with light-emitting diode (LED) technology. Due to significant improvements in their brightness in recent years, LED lighting is now widely used. As a result, the compact fluorescent lamp is being phased out.

In addition to the use of energy-efficient lighting systems, needs-based lighting control can help to make considerable energy savings, for example by aligning window facades to
face south when designing and constructing buildings. Automated lighting control using sensors is another technical solution that can be implemented in building stock undergoing modernisation.

Energy saving, needs-based lighting control can also be achieved through the deflection of light. With a light deflection system, mirrors, for example, are used to direct daylight from the window surfaces into areas where there is less natural light inside the building. The use of demand-driven lighting control, combined with energy-efficient lamps, is particularly beneficial in business and industry. In Germany, lighting accounts for up to 20 percent of electricity consumption in business.

Building automation technology is based on the use of sensors and actuators, which measure movement, light, temperature and room humidity, and on the measurements obtained to regulate the shading of window facades, the lighting, heating, air-conditioning and ventilation systems in a building. Options like motion sensors, video intercoms and control technology for blinds also increase comfort for residents and users. The actual values of the sensors are displayed and visualised via a user interface and the desired target values are set.