Heating system – which is the right one for you?

Gas heating provides heat in over 40  percent of German households. The benefits include technology that has been tried and tested over decades, which uses gas particularly efficiently thanks to condensing technology and the small footprint. Wall mounted gas boilers are particularly compact. This makes the heating system ideal for detached houses without a cellar or boiler room, but also for individual flats in apartment buildings. It is also important to know when making your decision: despite finite gas reserves, gas condensing technology has a future thanks to biogas and the possible admixture of hydrogen. In addition, Viessmann heating systems can be combined with heat generators based on renewable energies to create hybrid systems.        

Heating with gas –– a sensible decision when…

• You want a heating system with proven condensing technology for fossil fuels
• You only have limited space available for the technology
• You already have a gas connection or a liquid gas tank
• You want a modern heating system with a good price-performance ratio
• You want to have the option of being able to combine with renewable energies

Condensing technology makes heating with fossil fuel oil promising for the future. Just as with gas heating, the energy stored in it is utilised efficiently. Unlike the latter, however, space for the heating oil tank must be taken into account. How much that is, or how big the tank needs to be, depends on the size and energy status of the building and individual heating behaviour. In completely modernised existing buildings, the heating demand is significantly lower than in unmodernised buildings. As a general rule: An oil fired Viessmann heating system can be operated with bio-oil and combined with renewable heat generators.          

Heating with oil –– a sensible decision when…

• You want a heating system with proven condensing technology for fossil fuels
• You already heat with oil
• You have an oil tank or a corresponding room
• You want a reliable heat generator with a good price-performance ratio
• You want to have the option of being able to combine with renewable energies

Hybrid heating systems use several energy sources. This enables fossil and regenerative energy sources to be combined, for example, a gas or oil condensing boiler with an electricity-driven heat pump. This offers a lot of flexibility because innovative Viessmann controls ensure that the most efficient and economical operating mode is always selected automatically. As an alternative to the economical mode, there is an ecological equivalent. In this, the system works with a focus on minimising CO₂ emissions. Provided that requirements are satisfied, the integration of a photovoltaic system is also an option. This means that the power needed to operate the heating system can be produced immediately. An additional plus: gas hybrid heating systems are subsidised by the [German] state [local conditions apply].           

Hybrid system –– a sensible decision when…

• You already heat with oil or gas
• You want to rely on sustainable heat generation with a second heating system
• You always want to use the cheapest or most ecological heat supply automatically
• You would like to become more independent of the electricity supplier with a photovoltaic system
• You want to reduce the acquisition costs through subsidies (gas hybrid)  

A heat pump uses energy stored in the air, ground or water for heating. This is efficient and climate-friendly. And since the heat sources can be accessed in different ways, this type of heating is suitable for almost every type of building. If operating a ground source heat pump is out of the question due to the geographical location or a lack of space, an air source heat pump is a viable alternative. A very interesting point: Viessmann heating systems can also be used for cooling in summer. But it is important to know that, for technical reasons, heat pumps work efficiently primarily in combination with area heating systems. This should be considered especially when modernising existing heating systems. Your plans must also include sufficient space for the buffer cylinder required for storing heat. Subsides can help lower the higher costs for heating and installation.

Heating with the heat pump –– a sensible decision when…

• You want to use the freely available energy of the environment for heating
• You have a property with possibilities for geothermal collectors, probes or installation areas for an air source heat pump
• You also want to use your heating for cooling in summer
• You have underfloor heating or generously sized heating surfaces
• You have enough space in the house for a buffer cylinder with a capacity of up to 1000  litres
• You would like to reduce the higher costs for a regenerative heat generator with state subsidies

Solar thermal energy uses freely available solar energy as a heat source. In Central Europe, solar thermal systems are suitable for domestic hot water or as heating backup. It is not possible to cover the entire heat supply here. The savings potential is nevertheless impressive: annual savings of 60  percent are possible for DHW heating, and around 35  percent for the combined central heating backup. By reducing the utilisation of heating systems for fossil fuels, both energy costs and CO₂ emissions can be reduced. However, for the investment to be worthwhile, the roof must be unshaded and face south, west or east. And once again, this technology is state-subsidised too [subject to local conditions].

Solar thermal energy –– a sensible decision when…

• You want to use solar energy to heat water or as backup for the heating system
• You own a house with an unshaded roof surface facing south, west or east
• You want to supplement an existing heating system with renewable energies
• You would like to benefit from government subsidies for sustainable heat generators

A photovoltaic system converts solar energy into power. This can be fed into the public grid for remuneration or used by the owner –– for example to operate an electricity-powered heating system such as a heat pump. Due to the falling feed-in remuneration and rising electricity prices, the second option is currently much more interesting. To make the investment in such a system worthwhile, your roof should face south, west or east. In addition, make sure that it is not shaded by trees or mountains, etc. A state subsidy for photovoltaics and a storage unit will help to lower purchase costs.    

Photovoltaics –– a sensible decision when…

• You own a house with an unshaded roof area facing south, west or east
• You want more independence from the electricity supplier through power from the roof
• You want to produce your own power to run a heating system
• You want to export electricity to the public grid
• You would like to reduce the investment with subsidies for photovoltaics and power storage units

In addition to the heating, the indoor environment is also influenced by mechanical ventilation. This helps to remove moisture and thus prevents mould and possible damage to the building fabric. Systems with heat recovery can also relieve the heating system. This is because the heat stored in the extract air is not simply expelled to the outside. Integrated filters trap fine dust and pollen. The latter providing relief especially for allergy sufferers. Basically, a distinction can be made between centralised and decentralised ventilation systems. While centralised systems are more suitable for new buildings due to the installation complexity, decentralised systems are also a good solution for existing buildings and for ventilating individual rooms.

Mechanical ventilation –– a sensible decision when…

• You want to recover valuable heating energy from the extract air through heat recovery
• You want a constantly good and healthy indoor environment
• You want to prevent mould infestation
• You, as an allergy sufferer, want to filter particles from the air
• You want to eliminate fine dust and noise
• You wish to avoid draughts

Electric DHW systems only heat drinking water when it is really needed. This is particularly hygienic as the water does not stand in the pipework for a long time. In addition, DHW can be supplied independently of a central heating system. However, the comparatively high electricity costs make these systems mainly worthwhile for rarely used rooms such as the guest bathroom. Electric area heating systems are particularly suitable for newly built low-rise and passive houses. The energy demand for heating there is particularly low and so are the electricity costs. The benefit: rapid heating of the tiled floors in the bathroom and kitchen. Electronic Viessmann instantaneous water heaters and electric area heating systems combined with heat pumps provide a sustainable boost to system efficiency.

Electronic DHW systems – a sensible decision when…

• You only need hot water occasionally in some rooms
• You want to heat water independently of the central heating
• You want to heat a newly built passive or low energy house
• You attach importance to heating rooms quickly