Clever use of air conditioning systems
Whether at home or in the office: Midsummer temperatures in the house can quickly affect our well-being. The body increases the blood circulation of the skin to intensify sweating. Instead, the blood supply to the brain is reduced. The ability to concentrate decreases, headaches set in. Sun protection and air conditioning in the apartment can help. An air-conditioning system not only lowers the room temperature, but also regulates the humidity.
In general, the temperature difference between inside and outside should not exceed six degrees, as the body reacts to excessive temperature differences: Walking out of the heat into the cooled rooms feels just as unpleasant as walking out of the cool into the heat. Some people even react with a cold. This can also happen if an incorrectly set or positioned air conditioning system generates cold draughts.
Reducing energy consumption through good insulation
If an apartment or house is strongly cooled on hot days, HVAC air-conditioning systems can become real energy guzzlers, as they have to work continuously against the overwhelming heat. But you can effectively influence the temperature gradient:
Good insulation reduces the thermal permeability of the walls. They therefore have a double benefit: In winter the heating heat remains in the building, in summer the facade insulation – supported by thermal insulation windows – has a passive air-conditioning function.
You can control the penetration of heat: Reduce sunlight and warm outside air as far as possible during the day, and ensure adequate ventilation in the evenings and at night. The less sunlight and hot air heat up the bedroom, for example, the less work the air-conditioning system has to do. External blinds are much more efficient here than internal sun shading. Of course you can also ventilate on hot days, but you should do the same for heated rooms as in the cold season: Blow ventilation is better and more efficient than continuous ventilation.
Retrofitting an air conditioning system: Three types are available
Central air-conditioning systems can individually control the temperature of all rooms in the house from a common cooling unit. This cooling unit is usually located in the basement or in the attic. However, this requires a sophisticated system of air supply lines and air discharge ducts. This type of system is particularly suitable for new buildings. Equipped with a heat pump, it can also be used for heating. The costs depend on the size of the house and the individual air conditioning requirements.
Decentralised or split air-conditioning systems are installed separately for each room. They consist of two modules: The indoor unit cools, filters and dehumidifies the room air and transfers the heat absorbed in a coolant to the outdoor unit. There it is released to the outside air via a heat exchanger. The refrigerant thus cooled is returned to the indoor unit. The disadvantage of the system is that the outdoor unit can disturb the façade and cause noise with its fan. The unit prices are between 1,000 and 2,000 euros, depending on the version.
Mini air conditioners are devices that can be set up flexibly and that do not provide permanent air conditioning for larger rooms, but can nevertheless bring about a noticeable cooling effect. Hoses are required for the supply and exhaust air. Simple units are available from 300 to 350 euros.
How costly is retrofitting an air conditioning system?
All air conditioners produce noises in the interior that depend primarily on the design and setting of the fan. High-quality units operate almost noiselessly at a low level. In general, the air flow should be directed in such a way that it does not disturb.
Retrofitting an air conditioning system can be very labour-intensive, depending on the model. The easiest way to do this is with a split system for individual rooms. If indoor and outdoor units are installed, only the thin coolant lines have to be routed through the wall and the necessary power cables laid and connected. The necessary maintenance of air-conditioning systems includes, above all, changing the filter and checking the coolant, which only specialists are allowed to do.
However, homeowners can also cool their homes almost without using electricity: An air well ensures a reduction in the indoor temperature due to natural thermal dynamics. For this purpose, a 2.5 meter deep fountain-like pit is created in the garden, in which outside air transfers its heat to the surrounding soil in a gravel bed.
At the bottom of this pit, the cooled air is sucked in and transported into the building. After it has absorbed heat and cooled down the room, a small fan pushes it back into the open air. An underground air well can be created with relatively simple means and only requires the energy to operate the two small fans. If these are operated with regeneratively generated electricity, this type of air conditioning system is climate-neutral.