Performance by square metres
The basic rule is simple, for room cooling, allow approximately 60-100 W of capacity per square metre, depending on the number of windows, their orientation and whether the room is under a roof or on an intermediate floor. An apartment with large glazed areas facing south requires the higher end of this range, whereas a shaded room facing a courtyard will suffice with lower capacity.
| Room area | Approximate output | Typical example |
|---|---|---|
| up to 20 m² | 2.0-2.5 kW | bedroom, smaller room |
| 20-30 m² | 2.5-3.5 kW | living room in a flat |
| 30-45 m² | 3.5-5.0 kW | living area with kitchen |
| 45-60 m² | 5.0-7.0 kW | apartment with an open-plan layout |
An undersized unit runs practically non-stop at full capacity and still fails to cool the room adequately. An oversized unit cools the room quickly but frequently cycles, switching on and off in short intervals, which is less comfortable and unnecessarily wears out the unit. We therefore leave the exact output to a survey; the table serves only for initial guidance.
Split or multisplit
For a single room, a classic split system makes sense, one outdoor unit and one indoor unit. However, once you want to air-condition more rooms, the question arises whether to install several independent splits or one multisplit with a shared outdoor unit.
- Multisplits are cost-effectivewhen the apartment has limited space on the façade or balcony for multiple outdoor units: typically in a panel building, where installing a second unit would require further negotiations with the housing cooperative or the building's owners' association.
- Standalone split systems make sense, when rooms are far apart or on different floors of the building: a single outdoor unit would require excessively long pipe runs.
- A multisplit system typically has a slightly lower total output per unit area than two separate splits, as the outdoor unit is shared, making it more suitable for moderate operation in several rooms rather than continuous cooling of all rooms simultaneously.
Noise level
In rooms where people spend a lot of time: bedrooms, children's rooms, noise levels are more critical than in living rooms. Indoor units of modern models have noise levels in quiet night mode close to the background hum of a quiet household, but they vary from model to model. If you plan to install a unit in a bedroom, it is advisable to check the noise level specifically in night mode for the selected model, not just in normal operation: both values are usually listed separately in the catalogues.
The outdoor unit is noisier than the indoor one, and its placement (facade vs. Balcony) as well as distance from neighbours' bedrooms are mainly addressed in panel buildings. We cover this in detail in the article. Air conditioning for apartment blocks in Ostrava.
Indoor or outdoor temperature also determines performance.
The unit's capacity is not assessed solely based on the room area, but also on how large a difference between outdoor and indoor temperatures the unit must handle. In summer, when the outdoor temperature in Ostrava regularly exceeds thirty degrees, the unit must operate with a greater differential than during milder weather, therefore, for rooms with large glazed areas or without shading, it is usually better not to opt for the lowest recommended capacity from the table.
Unit brand
We install units from proven brands such as Daikin, LG, Samsung or Mitsubishi: the differences between them lie more in design, noise levels and controls than in the cooling principle itself. We therefore leave the choice of brand mainly to the customer's budget and preferences, while we recommend the capacity and placement of the unit based on the specific room.
Once you have clarified the performance and type, the next step is to arrange an appointment. An overview of how the installation proceeds and what affects the price can be found in the article. Air conditioning installation in Ostrava: price and process.
Air conditioning for supplementary heating too
Most modern units operate as air-to-air heat pumps and can provide heating in addition to cooling, during the transitional spring and autumn periods they can cheaply top up room warmth without switching on the main heating system. If you are considering this, let us know when selecting the unit: not every model delivers the same heating output at low outdoor temperatures.
Apartment orientation and room usage type
Apart from the room's floor area, how you actually live in the flat also matters. A kitchen with cooking and appliances requires slightly more capacity than a room of the same size without additional heat sources. An attic flat or one on the top floor of a panel building that overheats through the roof in summer usually needs higher capacity than an equally sized room in the middle of the building. We take these details into account during the survey; the capacity table serves only as an initial estimate.
Are you unsure about the performance required for your flat?
We will advise over the phone based on the apartment's dimensions and orientation.