Why is my LG LWG07-Series air conditioner not cooling the room?

Several issues can cause poor cooling: the thermostat may not be set cold enough, the air filter may be dirty, airflow may be restricted by furniture or curtains, or cold air may be escaping through open gaps. Additionally, frost on the cooling coils can block airflow — if this occurs, set the fan to Medium or High and the thermostat to 1 or 2 until the frost melts. (Page 20)