Tropical nights and hot days motivate many private individuals to buy their own air conditioning system. Proper planning and the right model are important to avoid high operating costs.
“I can’t stand the nights at home without air conditioning. The new device saves me in the summer,” says Christian Schäfer. The young man is standing heavily laden in the parking lot of a Cologne supermarket and wants to take his shopping to his apartment on the top floor. “The temperatures up there are getting higher and higher. I had to act and drove to the hardware store.”
Schäfer bought a mobile air conditioning unit for 400 euros, which now provides cooling. “Hopefully the electricity costs won’t be that high. But I’m taking the risk.” He opted for a so-called monoblock. These compact units are relatively inexpensive to buy: They are mobile and can be plugged into sockets anywhere.
Monoblock or split unit
The price ranges from 200 to 1,000 euros. At the desired location, the monoblock draws in the indoor air, cools it with a coolant and distributes it back into the room using a fan. The heat as a waste product is blown outside through a hose. Such models are flexible but not very efficient, says the consumer advice center. “Monoblock devices can have difficulty cooling sufficiently, especially in large rooms, rooms with direct sunlight or poorly insulated attic apartments,” says Hans Weinreuter from the consumer advice center.
Split units are an alternative. They are usually permanently installed by specialists and consist of two parts. There is the cooling unit in the room and an external unit that is mounted on the outside wall of the house. This is where the heat from the rooms is released to the outside. However, this requires drilling through the outside wall.
An air conditioning unit hangs on the outside of a residential building.
Different efficient, different expensive
“Split devices are more efficient and also dehumidify the indoor air. Many split devices also have an additional heating function,” says energy consultant Weinreuter. However, this performance comes at a price: a split air conditioning unit costs up to 2,500 euros, plus the cost of installation. In addition, split devices also have higher electricity costs.
Stiftung Warentest has calculated the electricity costs for the various options for a cooler home. In their example calculation, a fan costs around three euros per year in electricity costs, a split unit costs 39 euros and a mobile monoblock costs around 75 euros.
What is important when buying
When buying an air conditioning system, you should therefore pay attention to a few things. The cooling capacity is important and must be suitable for the room and the insulation. According to the consumer advice center, you should look closely at the energy label: the consumption in kilowatt hours per year and, of course, the noise level of the device are crucial here.
The energy label can be confusing: Classes A to D say nothing about the absolute power consumption, they only describe the efficiency of the air conditioning unit. If you just need a fresh breeze in your hot apartment, a fan might be a good choice, say consumer advocates. Fans cannot lower the temperature in the room like an air conditioning unit, but they do provide pleasant cooling. Moving air feels cooler than stagnant air.
What is important when operating
Consumer advisor Weinreuter also gives tips on how to use the devices correctly: “Only switch on the air conditioning when necessary, for example some time before going to bed. At night, it is advisable to switch the device off completely and cool with the windows open instead,” says the energy advisor. “Particularly with split devices, make sure to service them regularly, remove the condensate regularly and clean the evaporator and filter. This is the only way the device can work without problems.”
The Federal Environment Agency appeals to people to buy a device that is as climate-friendly as possible. “Many air conditioning units still use refrigerants that have a high greenhouse potential when they are released during assembly, malfunctions in operation or disposal,” says the Federal Environment Agency.
Criticism of air conditioning systems
The Federal Environment Agency is critical of a mobile device such as the one purchased by Christian Schäfer from Cologne. “They are inefficient and should only be used in exceptional cases, if at all.” Around 90,000 mobile air conditioning units are sold in Germany every year, according to the agency.
Instead of active air conditioning systems, which consume energy and cause greenhouse gas emissions, passive cooling measures should be used. Good protection against heat is provided by externally installed blinds, roller shutters or window shutters, as well as special window films that reflect the sunlight. Otherwise, as always in hot weather, keep windows and doors closed during the day and only ventilate at night.
Christian Schäfer is aware of the dilemma: “Of course, I won’t be using the system all the time. But sometimes my blinds are simply not enough. That’s when I’m happy about my new purchase at night.”