In order to choose the exact power required for our air conditioner, we must take into account not only the surface area and height of the room, but also various factors: exposure, thermal insulation, whether the room has heat sources such as a hob, oven or other.
We can quickly and reliably multiply the metric cubic metres by 35 W/m3 to obtain the power requirement in watts.

Example:

25 m2 ( surface ) X 2.70 m ( height ) = 67.5 m3

67.5 m3 X 35 W/m3 = 2362.50 watts

1 W corresponds to 3.41 BTU/h

Therefore 2362.50 watts X 3.41 = 8056.12 BTUs (a 9000 BTU is the ideal size).

The BTU (BRITISH THERMAL UNIT) is the unit of energy used in the USA and the UK, used in defining the cooling power of air conditioning systems as well as the heating value of fuels.
To convert W to BTU/h, it is sufficient to know that 1 W corresponds to 3.41 BTU/h. So to convert BTU/h to Watt you divide by 3.41; to convert Watt to BTU/h you multiply by 3.41.

The inverter is an electronic device placed inside the motor of the air conditioner, which makes it possible to adjust the power supplied by the device automatically according to the temperature of the environment.
Unlike the old ON-OFF systems that cool or heat equally and statically from switch-on to switch-off, inverter systems optimise energy consumption with an initial power increase that is then gradually modulated. This allows a lower absorption of electrical energy for the benefit of a clear cut in consumption as well as perfect environmental comfort.

A mono-split air conditioner consists of two units: an outdoor unit that is always installed outside the building on special wall or floor brackets; an indoor unit that can be of the split wall, floor console, built-in cassette or ducted type. Single-split systems are used for air-conditioning a single room, unlike multi-split systems (dual, trial, quadri or penta) which can air-condition several rooms at the same time using a single external unit.

The air conditioners without outdoor unit are of the monobloc type, consisting of a single component that acts as a terminal and generator.
To use this type of air conditioners, one or two pass-through holes on the external wall are required, in order to dissipate the heat produced by the work of the compressor.
They are decisive in contexts where it is not possible to install the outdoor unit due to urban planning or condominium constraints. Consequently they are a valid solution for buildings of historical prestige as they have zero architectural impact.

Before being disassembled and disposed of, an air conditioner must be deprived of the gas contained within the piping and the appliance through special containers to prevent the refrigerant gas from being dispersed into the environment. The recovery and disposal of refrigerant gases is mandatory by law, and the fluids that have reached the end of their life, being classified as special hazardous waste, must be treated as required by Legislative Decree 152/06 and disposed of correctly in authorized collection centers.
On the other hand, since the appliance is an electrical device, it is classified as WEEE waste which must be disposed of at municipal ecological islands or specialized collection centers.

Cleaning the filters of an air conditioner is an ordinary maintenance operation that can be carried out independently. To be able to operate safely, we recommend that you first turn off the power supply to the machine.
The filters are usually accessed by opening the front door of the indoor unit (depending on the models); once reached, they must be removed and taken to a comfortable position to be able to suck up the dust present. Subsequently it is possible to wash them (if of the washable type) with running water at low temperature without the use of solvents. To disinfect the battery, specific spray-type sanitizers are required, capable of eliminating mold, germs and bacteria.
To keep the air conditioner efficient it is necessary to keep the filters clean constantly, sanitizing them at each change of season.

The monosplit systems are composed of an internal and an external unit, while the multisplit systems are systems with several internal units and a single external unit: dualsplit, trialsplit, quadrisplit and pentasplit.
Multi-split systems are very popular, as a single outdoor unit is used to air-condition different environments, taking up less space on the facade to be dedicated to the external motor.

The expenses for the purchase of an air conditioner are deductible from the IRPEF paid, at 50% or 65% in 10 annual instalments; this is done by means of the 730 tax return or the Unico Form.
Deductible expenses are: total cost of products, labour, materials and consultancy.
- Building renovation: Art. 16 bis of Presidential Decree 917/86 BONUS CASA 50% deductions.
- Energy requalification: ex law 296/2006 ECOBONUS 50% and 65% deductions.
Deductions cannot be combined with any other incentive.

Clarification regarding Ecobonus 110% - If the intention is to replace the old air conditioner with a new one and take advantage of the 110% deduction, this must be combined with one of the driving works provided for by Law Decree no. 34 (Relaunch Decree). In order to benefit from the bonus it is not possible to simply purchase the air conditioner as the work must guarantee and demonstrate the improvement of at least 2 energy classes of the building. It will therefore be necessary to include the purchase in a larger project involving one of the main interventions and to present the APE, the certificate demonstrating the energy performance of the house, issued by a qualified technician.

For all energy efficiency measures not associated with one of the main measures, it is possible to continue to benefit from the 50% and 65% ecobonus.