How to choose the capacity of your air conditioner: guide to BTUs
To choose the right air-conditioner for a room, you must consider several factors, including room size, heat insulation, sun exposure and energy efficiency, in order to make the most suitable choice for the situation and also avoid unnecessary waste.
How to calculate the BTUs of the air conditioner
The power of an air conditioner is measured in BTUs (British Thermal Units). The BTUs needed depend on the size of the room, the number of windows, and the sun exposure. But it is important to specify that these are not the only factors to consider.
We have thought of simplifying the basic calculation by creating a configurator that can give you a starting point and show you how many BTUs you need.
How to convert BTUs to kW
When choosing an aircon, it is essential to understand the relationship between BTUs and kW as they determine the cooling capacity of the device.
Here is a quick guide to conversion:
| BTUs | Capacity (kW) |
|---|---|
| 9.000 | 2,5 |
| 12.000 | 3,5 |
| 18.000 | 5 |
| 24.000 | 7 |
What does this mean? The higher the BTU value, the higher the cooling power of the air conditioner, making it suitable for larger rooms or more people. Choosing the right power helps save energy, ensuring maximum comfort without waste.
Aircons: what types exist and which to choose?
Once the BTUs needed have been identified, depending on the result, there may be different types of air-conditioners that can meet the same need, and choosing the right one also depends on the layout of the room and your needs. The main ones are:
- Monosplit Air conditioners: Consisting of an indoor and an outdoor unit.
- Multisplit Air conditioners: Which have one outdoor unit and several indoor units.
- Air conditioners without outdoor unit: They have an indoor unit only.
The best choice in general always falls on single-split air-conditioners for several reasons:
- They are cheaper than the other options.
- The power of the outdoor unit is limited to one indoor unit improving performance.
- In the event of a failure, the air-conditioning replacement will only affect that room.
Multisplit aircons and air conditioners without outdoor unit: when are they the best choice?
When balcony space is limited and it is not possible to install several outdoor units, the ideal solution is the multi-split air conditioner, which allows more than one indoor unit to be connected to one outdoor unit, optimising space. If, on the other hand, the installation of an outdoor unit on the facade of the building is not permitted for aesthetic or regulatory reasons, the best choice is the air conditioner without an outdoor unit, which offers a discreet and functional alternative.
How to choose the right aircon for each room
When choosing an air conditioner, it is essential to also consider the room in which it will be installed. Depending on the room, considerations will follow.
Living room: In larger rooms with a greater number of people, a more powerful air-conditioning unit with a higher number of BTUs is required to ensure effective cooling.
The reference room must clearly be understood as being well delimited by doors, in the case of open space it is important to consider the room as a whole and therefore including the kitchen.
The same logic should also be applied in the case of industrial or office use. Large spaces or spaces with heat sources require more BTUs.
Saving Energy Using Air Conditioners
A sure way to save energy and reduce operating costs is to choose an air conditioner with a high energy efficiency class (A++ or A++). The energy class is indicated on the product label. Furthermore, it is not secondary that the room is well insulated, in which case you can opt for a model with a lower capacity. Conversely, if the room is poorly insulated or very exposed to the sun, you will need an air conditioner with a higher capacity.
To save money, should I opt for a less powerful air-conditioner and keep it on for longer?
We feel we must dispel the myth: opting for a less powerful air-conditioner and keeping it on for longer will not save you money. Let's start with a basic concept, i.e. the air-conditioning system is designed to reach a certain preset temperature and, once reached, it will keep it constant by ‘shutting off’ and restarting when necessary. Opting for a less powerful air-conditioner will only result in more wasted energy, because the device, if the room is too large for those BTUs, will never reach the desired temperature and will always run at maximum. This will also put more strain on the air-conditioning system and thus cause it to break more easily.
Can I install one air-conditioner in the hallway and cool all the rooms?
Installing one air conditioner in the hallway to cool all rooms is not the ideal solution. The unit would cover too large an area, making it difficult to reach the desired temperature. This would result in excessive energy consumption without ensuring effective cooling.