Capacity by square metres
As a rough guide, for a normally insulated room with standard ceiling height, you can expect approximately 100 W of cooling capacity per square metre. A 20 m² bedroom therefore requires a unit around 2 kW, while a living room with a kitchenette of 30-35 m² needs closer to 3.5 kW. This is only an initial estimate; the actual capacity required depends on window orientation towards the south or west, the number and size of windows, ceiling height, and how many people and appliances are typically in the room.
Flats on the top floor of a panel building, for example in Nová Ulice or Povel, tend to overheat during the day due to heat from the roof more than flats on middle floors, so it is advisable to estimate towards the higher end of the performance range. Similarly, attic rooms in detached houses in Lazce or Neředín, where the roof absorbs heat during the day, usually require a more powerful unit than a room of the same area on the ground floor.
We do not simply calculate the exact figure from a table at a distance. During the survey, we assess the apartment's orientation, shading and actual floor area to recommend an output that suits the specific room rather than an average.
Split or multisplit
A split system comprises one indoor and one outdoor unit for a single room. It is the simplest and most cost-effective solution if you are cooling only a bedroom or living room. In contrast, a multisplit connects multiple indoor units to a single outdoor unit; this is suitable when you want air conditioning in two or more rooms but do not wish to have several outdoor units side by side on the façade or balcony.
The disadvantage of a multisplit is that all connected rooms share one compressor, so when running at full capacity in all rooms simultaneously, the total output may drop slightly compared to each room having its own split. For standard living in a 3+1 apartment or a detached house, this is usually not noticeable; for larger layouts with high cooling demands in all rooms at once, it is addressed individually.
Wall-mounted or cassette unit
The wall-mounted unit is the standard for flats and detached houses. It is installed high on the wall where it does not obstruct and distributes air well throughout the room. The cassette unit is mounted into a suspended ceiling and is more suitable for offices, commercial premises or rooms with a suspended ceiling, where a wall-mounted unit would not fit visually or practically.
Cooling and mild heating in the shoulder season
Most split and multisplit units today can heat as well as cool, which is particularly useful during the transitional periods in spring or autumn when the heating season has not yet begun but the flat still needs warming up. This is not a substitute for main winter heating, but rather a practical bonus that ensures the unit is not left unused for ten months of the year.
Noise level of the outdoor and indoor units
In an apartment with a bedroom near the windows, or in a densely populated panel building, the noise level of the unit in night mode also matters. Indoor units of modern models are almost inaudible in quiet mode; for outdoor units, the difference between models is greater and is also affected by placement: a unit aimed directly at a bedroom window behaves differently than one on a less exposed side of the building. During the survey we also ask where you sleep and where you spend most of your time, so that the location suits noise considerations as well as technical ones.
Unsure whether your flat needs a split or multisplit system and what capacity? We will discuss this during a free survey and propose a specific solution.
What else helps keep an apartment cool
The unit's output is not the only lever. External shutters or fabric blinds on south- and west-facing windows can significantly reduce the heat entering the apartment during the day, meaning the air conditioner does not need to compensate for such a large difference. Similarly, it helps if the indoor unit is positioned so that the airflow is directed into the area of the room where you spend the most time, rather than just at the nearest wall.
Whether you live in an apartment block in Nová Ulice, a detached house in Lazce, or a flat in Hodolany, the selection principle is the same: first calculate the actual output based on the room, then choose between a split and a multisplit system, and finally fine-tune the placement to minimise noise. Specific prices for individual variants can be found in article on installation and price.