When the heating system is switched on, the following should ideally happen:

• The boiler heats the water.
• The pump transports the heated water through the pipes to the radiators.
• The radiators release the heat into the rooms.
• The cooled water flows back to the boiler and is reheated.

Unfortunately, many systems are not optimally adjusted. This means that less warm water flows through the radiators that are further away from the boiler, and these rooms do not get properly warm. Rooms close to the heating system are often too warm, even though the thermostats in both rooms are set to the same temperature.

To ensure that it is warm everywhere, an improvement can be achieved by increasing the pump output and/or the flow temperature of the heating water. However, this significantly increases heating costs, as the pump requires more electricity and the heating system consumes more fuel. In addition, flow noises often occur in the heating system, i.e., there is an unpleasant hissing sound.

Hydraulic balancing can be carried out by a heating engineer. First, the heat required for each room is calculated. The size of the room and radiators as well as the insulation are taken into account. Preset thermostats are then used to regulate the flow of hot water in the radiators and adjust it to the requirements of the room. This may require the installation of new thermostats. After hydraulic balancing, all rooms will be evenly warm and the flow noises will stop. In addition, heating costs will be reduced because the pump and boiler will be working optimally.

To keep living spaces warm and reduce energy consumption, heating should be continuous. Constantly turning the thermostats up and down consumes a lot of heating energy. It is not important that the radiator is always warm, but that the room reaches the desired temperature. A well-adjusted thermostat ensures this.

In rental properties with gas central heating and more than 10 residential units (or 6 residential units with a deadline of September 2024), hydraulic balancing is even mandatory. Since October 1, 2022, the "Ordinance on Securing Energy Supply through Medium-Term Measures" (EnSimiMaV for short) has been in force. This concerns measures that cannot be implemented in the short term and whose results are expected over the course of the next two heating periods. The regulation is initially valid for 24 months and also covers hydraulic balancing. Hydraulic balancing should have been carried out by September 30, 2023. In addition, according to the regulation, the owner bears the costs; they may not be passed on to the tenants. Hydraulic balancing can also help to reduce heating costs in rental properties that are heated with oil.