dust and dirt
Air conditioning always creates turbulence in the air. Warm air is sucked in, cold air is expelled. Dust is always sucked into the device. Air conditioners are equipped with filters to remove precisely these contaminants from the air. If the filter has not been changed for a long time, it will become clogged. The air can no longer circulate properly, so the cooling cycle no longer takes place properly. Therefore, clean the filter regularly. For split units, you should also clean the outdoor unit with a suitable spray to avoid dust and dirt.