WOLF oil heating

Understanding oil heating

Everything you need to know about oil heating

You will still find them in many existing buildings: oil-fired boilers. We offer an overview of the advantages of this heating system, the possible uses and combination options as well as the associated costs.

Oil heating still popular in old buildings

Around a quarter of all buildings in Germany produce their heat with oil. In new buildings, however, oil heating systems are hardly found at all. Modern oil heating systems are also very efficient thanks to condensing technology.

They are an important option in old buildings where alternatives are unsuitable - if no gas connection is available for gas heating, for instance. If you wish to combine your oil heating with renewable energies to create a hybrid system, you will not receive a subsidy, but you will still benefit from a reliable heating system.

01. What speaks for oil heating?

The various advantages of oil heating explain why this type of heating system is still so popular in Germany.

House in a rural location

Independent of infrastructure

The biggest advantage: Homeowners who purchase an oil heating system are independent of the local infrastructure. They do not need a district heating line nearby. This makes heating with oil still practical for buildings in remote rural locations.
Money coins - save costs

Lower costs for heating oil

Heating with oil is also inexpensive. Despite larger fluctuations in the price of oil as compared to gas, homeowners have generally paid less in the past for heating oil than for natural gas. Especially if they cleverly took advantage of the low-price phases.

Simple storage of oil for heating

Thanks to the storage capacity of the oil tank, you can plan one to two years in advance and ensure a secure long-term supply.

02. WOLF oil heating systems

WOLF Oil boiler COB-2

Oil condensing boiler COB-2

The COB-2 from WOLF provides cozy warmth with its two-stage modulating mode of operation - discover our highlight product among the WOLF oil condensing boilers.

Oil hybrid

Oil hybrid

Oil hybrid heating is the perfect solution for heating modernization. In addition to the reliable oil heating, at the same time with the renewable energy you reduce heating costs and heat more climate friendly.

03. When does it make sense to install an oil heating system?

  • Existing buildings

    Another advantage of oil heating systems: they can theoretically work in any building. However, oil heating demonstrates its true strengths in the modernisation of old buildings, where it proves very flexible. As mentioned above, you don’t need a gas connection and can typically use the existing heating pipe system without impairing your old building’s period appearance.


    This assumes that you have sufficient space in the cellar for the oil tank. Modern technology also allows for an underground tank in the garden for storing your heating oil.

  • New buildings

    Heating systems based on renewable energy make perfect sense in new buildings to contribute to climate protection. In buildings with good insulation, heat pumps provide the necessary heat in an environmentally friendly manner, making them particularly popular. Hybrid gas heating or a combination of various renewable energy sources are also options here.

    According to the Buildings Energy Act (GEG), heating exclusively with oil is not permitted in new buildings. A combination of oil with renewable energies, such as solar thermal technology, is generally feasible. However, most builders today choose one of the other options listed.


    Whether it makes sense to replace an old oil boiler with a modern oil condensing boiler is a question best left to an expert. Contact a heating installer in your area to find out more.

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04. How does modern oil condensing technology work?

If you use a modern oil heating system, you don’t have to forgo efficiency. Modern condensing technology ensures that the heating system makes optimal use of the energy content of the heating oil.

However, the radiators in the building must be designed for a flow temperature in the heating circuit that does not exceed 60°C. Only then does the condensing technology have the desired effect.


Heating systems with a condensing boiler are so efficient because they are able to reduce the heating losses of the system that arise due to hot exhaust gases. Older low-temperature boilers release exhaust gases at temperatures from 140 to 200°C. This wastes valuable heat.

In contrast, condensing boilers can extract the heat from these exhaust gases, cooling them down to 50°C. Watch the video below to learn more about how condensing technology works.


05. Combining oil heating with other heat generators

Even though subsidies are no longer available for oil hybrid heating, this combination is still a worthwhile choice in many cases. The classic version of oil hybrid heating consists of an oil condensing boiler and a solar thermal system. The solar collectors in such a hybrid system can provide 20 to 50% of the heat needed by the house over the year. Solar energy is particularly environmentally friendly and can leave the heating boiler with nothing to do from March to October. Another option for a hybrid heating system is to combine a heat pump with an oil condensing boiler. This especially makes sense for an air-to-water heat pump, since this type of heat pump requires a great deal of electricity on very cold winter days. In moderately to poorly insulated buildings, the electricity bill will rise accordingly. This is when the oil condensing boiler kicks in. On warmer days, however, the heat pump shows its strengths and supplies the house with climate-friendly environmental heat. If you would like to combine an oil heating system with a heat pump, you should take a closer look at the WOLF CHA Monoblock. With its understated design and quiet operation, this air-to-water heat pump will blend in perfectly with the look of your home.

New building with heat pump

Flat-plate collectors 

The TopSon F3-1 and CFK-1 flat-plate collectors from WOLF provide you with free solar energy for many years!

New building with heat pump

Tube collectors

The CRK-12 vacuum tube collector from WOLF achieves a particularly high solar yield throughout the year. This is absolutely climate-friendly, because solar energy does not cause any carbon dioxide emissions.

Heat pump in the garden

CHA Monoblock

The WOLF CHA Monoblock heat pump is sure to fit in with the overall design of your home and is perfect in the garden, out on the patio or mounted on the wall.

06. Costs of an oil heating system

In addition to the expense of the initial purchase, the total costs of an oil heating system also include operating costs and fuel costs. These depend on the price of heating oil.

  • Operating costs

    The costs of operating an oil system are not much higher than those of gas heating. You must also plan for the annual maintenance of your oil heating system.

    Tip: With a maintenance contract, you don’t have to stress over this every year, and you may even save on costs. 


    Every five to seven years, you should have your oil tank cleaned by a specialised company, which you can expect to cost €500 or more, depending on the design of the tank.

  • The price of oil

    The biggest factor in the ongoing heating costs, however, is the price of the fuel. Everyone knows from the petrol pump that the oil price fluctuates widely. But despite all prophecies of doom, it has not skyrocketed to unprecedented highs in some time.

    Nevertheless, no one knows exactly what this means for the future. On one hand, the CO₂ pricing in Germany, which has been in effect since 2021, has moderately increased the price of heating oil. However, the efforts to fight climate change could cause oil demand to fall globally. One conceivable result could be a moderate oil price in the future.

07. Oil heating pays for itself quickly

With a new oil condensing system, you can heat very efficiently. The new system will save money by using much less fuel. As a result, it will hit breakeven within just a few years.

If you also use renewable energies in a hybrid system, you not only support climate protection, you are also investing in a heating technology that will result in low heating costs over the long term while making you less dependent on oil price fluctuations as well.

Frequently asked questions about oil heating

  • The installation of oil heating as the sole heating system is prohibited as of 2026. However, legislators have allowed certain exceptions. For example, an oil boiler combined with solar thermal or a heat pump is still permitted. Exceptions also apply if

    • there is neither a gas supply
    • nor district heating nearby
    • or if an environmentally friendly alternative would not be efficient in your house.
  • Oil heating systems are subject to mandatory replacement according to the Building Energy Act (GEG) if they are constant temperature boilers that are more than 30 years old. Exceptions to this replacement requirement apply to buildings with a maximum of two residential units where the homeowner has personally lived since 1 February 2002. It is still possible to install a new oil heating system until 2026. After this, it will only be allowed in exceptional cases.

  • The typical oil tank for a single-family home holds between 1,000 and 3,000 litres of fuel. Larger tanks are possible in principle, but are subject to stricter safety requirements starting at 5,000 litres and up.

  • The switch from an old heating system to an oil condensing boiler is generally not difficult. Renovation of the exhaust gas line is one important measure to remember. This is done by having a heating technician install a plastic pipe into the existing chimney.

  • As with petrol for your car, there are also various qualities of heating oil. For the sake of the environment, you should always used low-sulphur heating oil. Premium heating oil also contains certain additives that guarantee the quality of the fuel for longer storage. Bio-heating oil contains a portion of renewable energy derived from regenerative materials and can be used in all oil heating systems without problems as long as it does not contain more than 5% biofuel.

Oil heating COB-2

Our recommendation: The oil boiler COB-2

50 years of experience have gone into the development and design of our top seller in the oil heating sector.