x-change heat pumps

Heating and cooling with a heat pump

When talking about comfort and cosiness, heating with a heat pump is no different than a conventional heating system based on oil, gas, or wood as the energy source. The only difference you will notice: At the end of the year, you will have significantly more money left in your wallet. Heat pumps are not only environmentally friendly, their operating costs are also low.

When you decide in favour of a heat pump, you are deciding on a cost-effective, sustainable and future-proof heating system. The market in this area is huge and not always easy for the amateur to find their way around. In the following we would like to shed some light on the heat pump jungle.

Heat pump compact - the most important bit in just 5 minutes

How does a heat pump work?

A heat pump basically works in the same way as a refrigerator. Just in the other direction. While a refrigerator takes heat away from its contents and emits it externally, the heat pump takes energy from the ambient air, the ground or ground water for example and transfers it to the heating system. In detail, this happens in 3 important steps:

1.) Heat generation

Depending on the type of heat pump, energy is generated from the ambient air, the ground or the ground water. This is done either using a ventilator (air heat pumps), which draws in ambient air, or in the case of a brine pump, suing probes or collectors which the so-called brine circulates in and withdraws heat from the environment.

2.) Condensing energy

The energy generated is then transferred in the heat pump via a heat exchanger to a second, independent circuit in which - the same as a refrigerator - an environmentally friendly coolant is circulating. The coolant vaporises through being heated. By being compressed in a compressor, the temperature of the coolant increases significantly. This heat is then withdrawn from the coolant again using another heat exchanger and is transferred to the heating system. The coolant condenses which means it is back in the circuit.

3.) Distributing & storing heat

The energy that the coolant transmits to the (central) heating system via the second heat exchanger is transferred from there to radiators, underfloor heating & co. in the shape of heated water or is stored temporarily in a storage system such as a buffer storage or hot water storage unit.

Heat sources for a heat pump

Ground / earth

The earth as a heat source. Might sound strange at first. But makes even greater sense when you look further into it. Energy can be extracted from the ground in two different ways. A distinction is made between probes and collectors which are used depending on the environment and the ground conditions.

Geothermal probes

Geothermal probes are inserted into a drill hole. For a normal detached house, this drill hole is around 100 metres deep. From a depth of 10 metres downwards, the ground temperature remains constant throughout the year. Providing ideal conditions for a heat pump. A frost-proof liquid circulates in the heat pump, the so-called brine. This brine takes energy out of the ground around the probe and feeds this energy in a closed circuit into the heat pump.

Geothermal collectors

Geothermal collectors work in a similar way to geothermal probes, only that the collectors are not inserted downwards but horizontally. At a depth of approx. 1.5 metres, geothermal collectors are laid out in serpentines. The brine circulates in these pipes - the same as with the geothermal probe - and collects energy from the ground which the ground has absorbed from either sun irradiation or from rain water for example.

Outside air / ground water

Apart from the earth, the outside air or also the ground water - where ever available - are also suitable as an energy source for a heat pump.

Outside air

The principle is simple: energy is extracted from the outside air with an air heat pump. This even works in the winter when the temperatures are below 0° degrees as long as the boiling point of the coolant used is lower than the outside temperature (which is the case as a general rule).

This principle is what for example the x-change air/water heat pumps by Kermi make use of.

Ground water

Apart from the earth, a heat pump can also extract heat from the ground water. The average temperature of the ground water is also easily enough to operate a heat pump even on cold days. Ground water heat pumps are always suitable where it is easy to access the ground water and of course, ground water is available in sufficient quantities.

What are the benefits of a heat pump?

Low space requirements

An oil or gas tank, a pellet or wood chip bunker - they all needs plenty of space - which comes at a premium in old and new buildings. Apart from the space requirements however, the smells coming from oil & co. also play a role - we are all familiar with the typical smell of a boiler room. With a heat pump, none of this is necessary.

Heating and cooling with a single device

We have already mentioned it: in principle, a heat pump when heating works the same way as a refrigerator, only in reverse. In the summer of course, this can be reversed and on hot days, the heat pump can also be used to cool, for example in association with x-net panel heating and cooling.

Virtually no maintenance costs

Heat pumps are very easy to maintain and are extremely low maintenance. Due to their matured technology, heat pumps are real long distance runners and are leap years ahead of many other heating systems when it comes to durability and maintainability. Gradual loss of performance does not happen with heat pump, regardless of whether being used on the first day or after 25 years: the output of a heat pump always remains the same.

No emissions, no chimney sweep

You do not need a chimney if there are no emissions. And without an chimney, you don't need your annual visit from the chimney sweep. That is not just a good thing for the environment - your wallet will be pleased too.

Controlling your heat pump intelligently and comfortably

The technology in a heat pump can be controlled precisely. Perfect conditions for intelligent control with Smart Home applications and apps. That not only provides greater comfort, but provides additional savings potential.

Completely independent with solar power

If you operate your heat pump with electricity you have generated yourself (e.g. with a solar panel system) and you use intelligent control, then you are completely independent of oil, gas, electricity, and wood prices and will generate electricity virtually at zero cost.

When is it economical to have a heat pump?

The answer to this question is actually quite simple: Always. Fossil fuels such as oil, gas or coal do not have a future in private households, particularly with regard to the high CO2 emissions. With a heat pump, you are investing in sustainable and a future-proof type of heat source which your wallet will thank you for - apart from low maintenance costs, you will also benefit from attractive financial incentives.

Financial incentives and finance

The Federal Office of Economics and Export Control (BAFA) provides financial incentives for investments in heat pumps covered by a range of different financial incentive programmes. It does not matter here whether you are working on a new-build or refurbishing an old building.

Did you know: To generate four kilowatt hours of heat energy, a heat pump only needs approx. one kilowatt hour of electricity. And then if the electricity is also sourced from regenerative energy sources , then the energy saving duo is perfect.

What should I pay attention to when selecting a heat pump?

Ultimately the selection of suitable heat pump technology depends on a wide range of factors, such as the size of the property, the local conditions, the location and also the available budget.

Once the question on the right technology has been decided, then you need to select the most suitable heat pump model for your project. Here, factors such as floor space, the type of heat transfer in the house (e.g. radiators / panel heating) or also the insulation in the property all play a role.

These questions can only be answered in detail on location by an expert. If you are still looking for an experience expert, then you can use our Specialist partner search to find a competent Kermi specialist partner near you. They would be glad to be at your disposal to answer any questions and provide assistance in all matters concerning the procurement and installation of a heat pump.

Specialist terminology to do with heat pumps explained simply

bivalent operation

A second heat source exists which work in parallel (bivalent parallel) or alternatively (bivalent alternative) to the heat pump.

In bivalent parallel operation, both heat sources work in parallel at a pre-defined outside temperature. If the heat sources run bivalent-alternatively, then they operate alternately.

monoenergetic operation

The heat pump works up to a predefined outside temperature, if the outside temperature is lower than this, an electric screw-in heater switches on as well which - like the heat pump - is operated using electricity.

monovalent operation

The heat pump is the only heat source in the building.

Coefficient of performance (COP)

The coefficient of performance (COP) of a heat pump is a parameter determined under standardised test conditions for the output of a heat pump. The COP is suitable for an initial comparison of different models and provides insight into their output and the heat source used.

The sequence of numbers and letters that initially looks quite cryptic is quite easy to decipher.

The letters A, B and W stand for the terms air, brine and water respectively. Assuming that the COP of our heat pump was B2W35, then that would mean that a brine heat pump at 2 degrees brine temperature would generate hot water at a temperature of 35 degrees under normal conditions.

Annual performance factor (APF)

The annual performance factor compares the energy generated with the energy required to do so providing an efficiency factor. That means, the higher the annual performance factor, the more efficient the heat pump is.

Depending on the heat source, the Annual performance factor is usually between 3.5 and approx. 4.5, i.e. that one Kilowatt hour of electricity is converted into between 3.5 and 4.5 Kilowatt hours of heating output.