Since the heatwave at the beginning of the century, air conditioning has become a must in our countries. Because, even if it can be expensive in terms of electricity consumption, the comfort it brings in (too) hot weather is undeniable. But you have to choose wisely...

The summer of 2003 is still fresh in everyone's mind, with a long period of particularly severe heatwave. Until then, air conditioning was rarely used in private homes in our regions, although it has been commonplace in other parts of the world since 1930. The heat wave of 2003 and the increasing global warming have since led to an explosion in sales of air conditioning systems. And many new houses and flat blocks are now designed with 'air conditioning'. In the warmer months, it provides undeniable comfort. This almost universal availability and the wide range of products on offer have also led to a fall in prices, bringing air conditioning within reach of all budgets. Especially since the systems on offer range from the simplest - even basic - to the most sophisticated, to the point where it is sometimes difficult to find your way around. Here is an overview and practical advice. But this does not replace the absolutely necessary advice of a professional. Only a "professional" will be able to guide you towards the best solution according to all your own parameters. And, last but not least, after-sales service.

But first, a quick reminder. The very principle of operation of an air conditioning system is very simple. And it is no different from our faithful fridge, which keeps what is inside cool, in this case the room to be cooled. Like the fridge, an air conditioner does nothing more than produce cold air and evacuate hot air, by sucking the ambient air into a hoover where it is cooled and filtered before being reinjected by a fan, while the calories are sent outside.

While the mechanism is simple, the choice of system is much less so. Both because two types of air conditioning prevail and because many parameters must be carefully taken into account before deciding. These include the insulation of the property and its exposure, the number of windows, the size and quantity of the rooms to be cooled, and the use to which the system will be put. The choice of equipment will depend on whether it is used intensively, moderately or occasionally. For fixed systems, the cost of installation and annual maintenance should also be taken into account.

And there are two main things to remember. Firstly, it is generally considered that 100 Watt/m2 is needed to air-condition a living room, and 80 Watt/m2 for a bedroom. The impact of electricity consumption will therefore also be one of the elements in the calculation, along with the energy class of the appliance. Secondly, the potential of air conditioning should not be abused, otherwise health problems (chills, headaches, etc.) may occur. An air-conditioning system can cause the room temperature to drop by 6° to 8° centigrade. But a difference of 7° between the outside and inside is a maximum, precisely to avoid health problems. Most manufacturers and installers advise that the room temperature should not fall below 18°.

And, of course, it is obvious, but it is often worth pointing out the obvious: nothing can obstruct the air conditioner, nor can it be directed towards so-called "parking" areas such as chairs, tables, beds, etc.

What are the two main systems mentioned above?

Packaged air conditioner

This is the ABC of air conditioning, the simplest and cheapest system. But it is also the most basic and therefore sometimes completely unsuitable. It is characterised by the flexible pipe for the evacuation of hot air stuck in a door or a half-open window, which you have no doubt already seen.

This single-package air conditioner is only suitable for one room, which should not exceed 30 m2 . It is therefore a one-off unit and is usually equipped with wheels, so that it can be used in any room as required. But it is generally rather noisy. And greedy, even very greedy, in energy.

Several models are equipped with self-cleaning filters. This is important to know when purchasing a model, as the filters must be cleaned regularly - otherwise bacteria will be released into the air - as well as the fan.

Some of them are reversible and can therefore be used as auxiliary heating in winter.

Split air conditioner

The characteristic of this air conditioner is that it consists of at least two units (if there are more, it is called a multi-split air conditioner). One is installed inside, where it diffuses cold air, the other outside where it rejects warm air, and they are connected by pipes through which refrigerants circulate.

The outdoor part is the loudest part of the installation, which is a significant advantage compared to the noise level in the room(s).

The "split" system, which is much more powerful (up to 4,500 Watt) than the monobloc, can air-condition rooms of up to 40 m2.

Again, some manufacturers offer castors for the indoor unit, allowing it to be moved from room to room, with the hoses connecting it to the outdoor system being flexible rather than rigid.

As soon as the "split" air-conditioning has more than one unit inside (there is always only one outside), it necessarily becomes fixed and the vents are almost always fixed on a wall, high up, which saves space. This is a clear advantage over the monobloc and the mobile split. In addition to the reduction of noise and the air conditioning of several rooms, the "split" is much more aesthetic - or less unattractive... - and efficient. It is also, therefore, much more expensive. If only because it has to be installed by an installer and annual maintenance is compulsory.

Several manufacturers also offer a reversible "split" which allows it to be used for heating in winter. This is much more efficient than the reversible monobloc. Because here, the mechanism gives off about three times more energy than it consumes. Depending on how it is used in the summer, this could reduce the extra cost of electricity consumption during the summer.