Dusseldorf As the temperature rises in summer, so does the desire for air conditioning. In a recent survey by the comparison portal Verivox, 13 percent of those surveyed said they already had an air conditioner at home – a further 16 percent were planning to buy one.
The NRW consumer advice center is also noticing a growing interest in the devices – because of the warm days, but also with a view to next winter. Permanently installed air conditioning systems are usually also air-to-air heat pumps – i.e. heaters that provide warm air directly without first having to fill a radiator.
Consumer advocate Reinhard Loch says: “A market will increasingly develop for air-to-air heat pumps because they can be used to cool rooms and, under certain circumstances, to comply with the requirements of the heating law at the same time.“
What is a split air conditioner?
High-quality, permanently installed air conditioning systems are often so-called split air conditioners or split heat pumps. This means that they consist of an indoor and an outdoor unit. A coolant line runs through the wall and connects both units together. So basically, an air-to-air heat pump is the same as an air conditioner.
Claus Handel, Technical Manager of the Building Climate Association, says: “In 95 percent of cases, split air conditioning systems can also be used as heat pumps. Virtually all fixed split air conditioners on the market today are also heat pumps.”
There are also air conditioners that consist of only one unit, so-called monoblocks. They are often mobile, i.e. not permanently installed. And partly not suitable for heating.
What are the advantages of a split heat pump?
Because split air conditioners work like heat pumps, they have an energetic lever. This means that they are not power guzzlers, but produce several kilowatt hours of heat from one kilowatt hour of electricity, for example.
There are also additional functions. The Central Association for Sanitary, Heating and Air Conditioning (ZVSHK) states: “Air-to-air heat pumps can not only be used for heating and cooling, but also supply the home with fresh air.”
This ensures a more pleasant indoor climate and can also prevent or prevent the formation of mold. In addition, air-to-air heat pumps could also clean the air of dust and pollen.
What is the disadvantage compared to conventional heat pumps?
At the same time, air-to-air heat pumps are less comfortable than air-to-water heat pumps. Consumer advocate Loch says: “If you want to heat the entire apartment with an air-to-air heat pump, you need large airflows.” You may feel and hear these airflows – even if there are high-quality devices whose sensors detect people in the room and direct the airflow past them.
When does a split air conditioner make sense?
In certain cases, split air conditioners can completely heat the apartment or house in winter – and are cheaper than gas heating. Handel says: “In efficient buildings, air-to-air heat pumps can be used solely for heating.” And: “If you are in the process of renovating a house, it makes sense to also install an air-to-air heat pump at the same time.”
According to Handel, air-to-air heat pumps can be a sensible alternative to air-to-water heat pumps, especially in offices or high-efficiency houses – also because they are more efficient. This is because heat is lost during the additional heat transfer from air to water.
However, this solution is less suitable in poorly insulated houses. In addition, according to Handel, you need an extra solution for hot water with an air-to-air heat pump.
Consumer advocate Loch therefore says: “In Germany, air-to-air heat pumps are mostly used for cooling or as additional heating.” Air-to-air heat pumps can also be installed in individual rooms that are to be cooled in summer.
How complex is the installation of a split air conditioning system?
Christoph Brauneis, spokesman for the Association of German Refrigeration and Air Conditioning Specialists, says: “It takes a craftsman about a day to install an air-to-air heat pump. If an entire apartment is equipped with air conditioning units, maybe a little longer.”
The refrigerant lines leading into the building are about the thickness of a finger. All you need to do is drill a few holes, and then the lines can be laid relatively easily.
Consumers in Germany recently waited half a year or longer for the delivery and installation of an air-to-water heat pump. According to experts, there is a chance that air-to-air heat pumps will be faster.
Brauneis says: “Our workshops currently have enough orders on average for the next 15 weeks. But one or the other may still find time in between for the relatively simple installation of an air-to-air heat pump.”
How much does a split air conditioner cost?
The bottom line is that split air conditioners are cheaper to buy than air-to-water heat pumps. The ZVSHK says: “Compared to other heat pumps, air-to-air heat pumps are a little cheaper to buy and a little easier to install because they don’t need heating pipes or radiators. However, this requires air ducts, air pipes, air filters and air outlets.”
Depending on the size of the apartment, the purchase and installation costs for an air-to-air heat pump are between 12,000 and 25,000 euros according to the ZVSHK – the costs for air outlets in the ceiling, pollen filters or air humidifiers may also have to be added.
If you only want to buy a single split air conditioner and don’t want to supply the whole apartment with it, you can do it much cheaper. Handel says: “You can estimate around 2000 euros per room.”
Which split air conditioners are supported?
The federal government financially supports the installation of heat pumps – and thus also of heatable air conditioning systems. Depending on the case, the state covers 25 percent of the costs, or even more.
Exactly which devices are funded is on a list from the Federal Office of Economics and Export Control (Bafa), which can be found on the authority’s website. It can be viewed at this link.
Can you also use an air-to-water heat pump as an air conditioner?
That is possible. Cold water is then fed into the radiators instead of warm water. Handel says: “Basically, from a purely technological point of view, heat pumps can always cool, and air conditioners can always heat as well.” However, both properties are not technically implemented in every device: “If you use an air-water heat pump for cooling, it also needs a controller that prevents condensation on the surfaces.”
This means that when cold water flows through pipes and radiators, condensation can form there and mold can develop. Not every heat pump is designed to prevent this.
Consumer advocate Loch says: “If you use an air-water heat pump for cooling, the heating surfaces have to be very large so that the surface doesn’t have to be very cold and stays above the dew point.”
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