Heating: heat pumps in old buildings too: facts about electricity consumption and costs

The war in Ukraine and the one it triggered gas conflict with Russia has had a massive impact on energy prices in Germany. This is also reflected in inflation – the Federal Statistical Office (Destatis) once again put the inflation rate for November in double digits. “We are also increasingly observing price increases for many other goods in addition to energy,” says “Destatis” President Georg Thiel. However, the prices for heating oil or gas still make a large contribution to inflation above the ten percent mark – all the more interesting alternatives are becoming.

Heat pumps are also an option in old buildings: the “flow temperature” factor is decisive

With regard to the development of heating oil prices and the gas problem, these are about pellets or the heat pump. It should be noted that the price of pellets has also risen. Although both heating oil and pellet prices have fallen a little compared to the autumn, prices of around 200 euros per tonne like before the energy crisis are still a thing of the past. An alternative to the pellet heating system is the heat pump. In contrast to a pellet stove or pellet heating system, a heat pump requires less space.

The device can be placed inside or outside. “There are different models,” explains Sven Kersten from the German Heat Pump Association (BWP) in an interview with our editors. It doesn’t matter whether you live in an old or new building. Because the power consumption and costs of a heat pump can pay for themselves over time, even in older buildings – the decisive factor is the flow temperature. “That’s the temperature produced by a heat pump.” The higher the flow temperaturethe higher the energy expenditure required for this.

Electricity consumption of heat pumps in old buildings: expert gives concrete assessment

This means: In old buildings with poor insulation, the flow temperature can be higher than in well-insulated new buildings. When reference value calls Kersten 55 degrees. You can easily check this by turning on all the radiators in the house and checking whether the optimum temperature is being reached in all rooms. In the case of heat pumps, there is also the heating surface factor. The larger the heating surface, the better the heat can be distributed in the house. Larger radiators or wall or underfloor heating also play a role when it comes to efficiency.

But one thing is certain: “The statement that a heat pump is only worthwhile in new buildings is nonsense,” says Kersten. If a house is so poorly insulated, switching to a different heating system would also feel like a pellet heating don’t count. It is correct: The power consumption of a heat pump in old buildings can be higher – but this is also the case with other heating systems. The purchase of a heat pump therefore depends on individual factors. The question – where a heat pump makes sense – cannot be answered in general terms. In principle, the heating system can be a sensible solution in many types of buildings.

Heat pumps in old buildings: hybrid heating systems and subsidies – you should take that into account

Kersten: “Also hybrid systems are conceivable.” Anyone who has installed an oil heater in an old building, for example, can use it in parallel with a heat pump. “That can be an option in apartment buildings, for example.” In this context, however, you should take a closer look at the state subsidies for heat pumps. Because Anyone who replaces their old oil or gas heating system with a heat pump will receive a higher subsidy, which means that in individual cases it could even be more attractive to expand the oil heating system and receive the higher subsidy.

Kersten Bürger recommends that you take a close look at how often you actually need oil or gas heating in combination with a heat pump fuel heating still installed. Regardless of the age of the building, it always makes sense to hire a craftsman specializing in heat pumps. “You should pay attention to good references and experience – even if you have to wait a little longer for your heat pump in case of doubt.” According to Kersten, nationwide Internet offers should be treated with caution.

Calculating the power consumption of a heat pump: You should know these terms

If there are problems with the heat pump, having a local contact is very important, says Kersten. There is also no difference between old and new buildings when it comes to the question of which type of heat pump is the right one. “In most cases, a classic air heat pump pays off. Only in large buildings can a ground or groundwater heat pump be the better alternative.” The background: In the case of a ground or groundwater heat pump the water – or the heat in the earth – must be tapped. The devices are therefore more expensive to purchase and install.

If you want to know how high the power consumption a heat pump can calculate this using a simple formula: (heating capacity/AC) x heating hours = electricity consumption. the Annual performance factor (JAZ) stands for the efficiency of a heating system that is operated with a heat pump. It reflects the relationship between the energy supplied (electricity) and the heating heat actually generated over a period of one year. The power consumption can be calculated based on the increase in the heating output (in kWh) and the heating hours (operating time).

Heat pumps are also useful in old buildings – but there are a few things to consider

Kersten: “Under certain circumstances, in addition to the heat pump, the installation of a photovoltaic system This is usually always useful in new buildings. In old buildings, factors such as the size of the roof or the condition are important. Here, too, it is advisable to speak to a specialist advisor. Consumer advice centers, among others, often offer advice or seminars. Kersten also assumes that after the demand boom in autumn 2022, heat pumps will be easier to get again in the coming year.

The conclusion to heat pumps: The installation of the heating system can also pay off in old buildings. Factors such as the flow temperature, the size of the radiators or the structure of the building should be kept in mind. However, the general statement that heat pumps do not pay off in old buildings is wrong. Rather, it depends on individual factors. One is all the more important good advice. Kersten: “Ideally, it is a specialist company with several years of professional experience and good references.” The BWP also offers a matching one Specialist partner search via their own website.

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