Water heaters for on-demand supply in residential buildings

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The picture shows a close-up of the indirect coil in a DHW cylinder.

Depending on the number of occupants and their consumption habits, the hot water demand in residential buildings can vary greatly. But this is not the only factor to consider when planning the hot water supply. If DHW is to be provided centrally, the heat generator also has a role to play. In addition to the heating water, it then also heats the drinking water. However, central DHW heating is not always an option. If, for example, only a little hot water is needed, or only occasionally, decentralised water heaters are a good alternative. To meet the various needs and circumstances, Viessmann offers a wide range of DHW cylinders and water heaters. The variety of capacities and designs ensures a reliable and energy saving supply in every residential building.     

Combination with solar thermal in the central heating system

If connection to the heating system is planned, Viessmann Vitocell DHW cylinders and heating water buffer cylinders offer you a wide range of options. They can be combined with both classic condensing boilers and heat generators based on renewables. In addition to heat pumps and solid fuel boilers, the combination with a solar thermal system is also possible. This allows you to make use of the freely available energy of the sun to heat water for your daily needs, as well as heating the living space. By integrating solar thermal into the heating system, you can cover around 60 percent of the annual heat demand for DHW heating and 20 to 30 percent of the heat demand. This saves energy and reduces heating costs at the same time.

How do you find the right water heater for your needs?

How large should the capacity of your DHW cylinder or heating water buffer cylinder be and what should you look out for when combining it with a solar thermal system? Our partners can help you with questions like this. If you would like to find out more about the Viessmann product range before having a no-obligation consultation, the product catalogue will help. Use the filter functions to narrow down the selection, for example according to application area. For detailed product suggestions, we recommend the product finder.

DHW cylinders as all-rounders

The picture shows a Vitocell 100-W DHW cylinder with a Vitodens 100-W wall mounted gas boiler in a bathroom, opposite a tumble dryer on top of a washing machine.
Vitocell 100-W DHW cylinder with a Vitodens 100-W wall mounted gas boiler

DHW cylinders store the drinking water and heating water that has been heated by the connected heating system and make it available when required. The effective thermal insulation ensures energy saving operation and a high level of comfort for the occupants of the house. Different designs and sizes make the Viessmann Vitocell DHW cylinders versatile. If there is only limited space available, cylinders installed below the boiler are an option. They offer sufficient space for a condensing boiler to be installed on top. For a greater demand, on the other hand, Viessmann's floorstanding DHW cylinders are ideal.

Benefits of DHW cylinders at a glance

  • Reliable provision of heating water and DHW
  • Effective thermal insulation for high energy efficiency 
  • Variety of sizes and designs available
  • Can be combined with all heating systems
  • Can be extended to form a cylinder loading system

Heating water buffer cylinders for the heating system

Viessmann heating water buffer cylinders ensure that the heating system works efficiently. They store surplus heat and make it available at a later time. If a solar thermal system is integrated into the heating system, this kind of cylinder is indispensable. It allows the thermal energy to be used even when the sun is not shining. With a multi mode Viessmann buffer cylinder, not only heat from the solar thermal system can be stored, but also heat from other heat generators. In combination with a freshwater module, DHW heating is also possible.

Benefits of heating water buffer cylinders at a glance

  • Storage of heat for later use
  • Increased efficiency of solar thermal and heating systems
  • Multi mode systems for several heat generators
  • Addition of freshwater modules possible
  • Can be combined with all heating systems  

Freshwater modules for hygienic DHW heating

If a freshwater module is added, a heating water buffer cylinder can also provide domestic hot water. The combination of these two components is therefore an alternative to the classic DHW cylinder. As the water is only heated when required using the instantaneous water heating principle, it is particularly hygienic. The Viessmann Vitotrans freshwater modules are pre-assembled, compact units that can be easily wall mounted or installed directly on the buffer cylinder. Optimally coordinated components ensure a constant water temperature even with different draw-off rates.

Benefits of freshwater modules at a glance

  • Heating of drinking water with a buffer cylinder
  • Particularly hygienic thanks to the instantaneous water heating principle
  • Easy installation on the wall or cylinder  
  • Constant water temperature
  • Can be used in low temperature heating systems

Electric DHW systems for decentralised supply

The picture shows a Vitotherm E15 mini instantaneous water heater in a modern guest bathroom.
Vitotherm E15 mini instantaneous water heater

Decentralised electric DHW systems provide hot water on demand. This ensures a high level of convenience, is hygienic and keeps electricity costs low. Moreover, since the systems are connected very close to the draw-off points, heat loss from the pipework can be prevented. This makes electric DHW heating energy efficient. Viessmann Vitotherm instantaneous water heaters and electric hot water storage heaters are low-maintenance and easy to retrofit. While instantaneous water heaters heat small quantities of water to the exact degree, small and wall mounted storage water heaters hold somewhat larger volumes.

Benefits of electric water heaters at a glance

  • Fast and hygienic supply of DHW
  • Prevention of heat loss
  • Straightforward installation and maintenance
  • Water heated to the exact degree
  • Available in many output stages, sizes and colours