The time required to cool down a large room after an air conditioner stops working suddenly can vary depending on several factors, including the size of the room, insulation, ambient temperature, humidity levels, and the initial temperature inside the room. However, it's important to note that without an actively functioning air conditioner, the cooling process will be significantly slower or may not be possible in extreme cases.
If the AC unit has completely stopped working, the room will gradually start to warm up as the cooling effect diminishes. The time it takes for the room to reach its ambient temperature will depend on the factors mentioned above. In general, it can take anywhere from several hours to a day or more for a large room to return to its ambient temperature without an operational AC unit.
To help cool down the room during this period, you can employ alternative methods like opening windows to allow natural ventilation, using fans to circulate air, utilizing shades or curtains to block direct sunlight, and minimizing the use of heat-generating appliances.
It's important to address the cause of the AC unit malfunction and consider contacting a professional HVAC technician to diagnose and repair the issue as soon as possible to restore the cooling functionality and maintain a comfortable indoor environment.