First the most obvious, but easily solvable cause of the warm air from the air conditioner switch is in the wrong position. This refers to the reversible models, which can operate either on the production of cold and warm air. Make sure the switch is in the desired position. Or the temperature that you set on the remote, above the temperature that prevails in the room. The second major reason is the malfunction of the compressor or condenser or else - the most common cause of disorders of the condenser - from the system leaked freon. It is inert, safe gas that fills the air conditioning system. Periodically (1 time in 2-3 years, the air conditioning system should be refilled with freon, which gradually escapes through small fissures or defects in the system. When the pressure of the freon in the system the air has nothing to cool off and as a result, at the output it will maintain its temperature. The third reason for the lack of cooling air may be too low voltage in the grid that does not trigger the compressor to work. Usually this applies to those houses where periodically there are problems with electricity. The problem may lie in defects in wiring that connects the outer and inner part of the air conditioner. Also, the cause of the defect may be contamination of the heat exchanger, air filter, indoor unit. So, if, for example, do not carry out regular cleansing of the filters in just two months formed a layer of dust reduces the efficiency of the device in 2-2,5 times: as a result activity proper refrigeration of the device is broken, the compressor receives the freon in the gaseous not, as expected, and in the liquid state, which gradually leads to breakage of the compressor, and in this process, the air conditioning stops efficiently to cool the air to the desired temperature. In any case, the solution of such problems need to trust the specialists of service centre on servicing the air conditioner, which are qualitatively carry out the necessary diagnosis and repairs that led to such anomalies in the operation of the air conditioner.