The aircon cools a room by sucking the heat from the air. When the aircon is not running optimally, it is not able to pull in the heat from the air and emit it out at an efficient rate, thus taking a longer time to cool a room.
This may be due to several reasons:
The Aircon is Heavily Loaded A heavily loaded aircon necessitates a longer cooling time. Switching off the spot lighting and/or electrical appliances that general substantial amount of heat load may help to ameliorate this problem.
Refrigerant Leakage The aircon operate at a standard amount of refrigerant in the system. This refrigerant function is to absorb the internal hot temperature and reject to the outdoor. When there is refrigerant leakage, the ability of the aircon to cool a room efficiently is reduced.
Insufficient Airflow An inconsistent airflow coming through the condenser will lead to the aircon being unable to dispel heat out, leading to slower cooling. A low airflow can also lead to the evaporator being frozen, consequently damaging the compressor unit, and thus contributing to inefficient cooling.
An Inefficient Filter An aircon filter attracts particles from the air so as to keep the aircon clean. When an overloaded filter is not changed or clean, the airflow will be decreased due to blockage. This will then decrease the cooling effect. Further, the overloaded filter will also emit congested air through the system. To pre-empt the above problems, regular servicing of your air con is optimal. A trained air con professional will be able to detect problems early and carry out exacting measures.