Popular types of window fans include manually and electrically reversible models that can exhaust or draw air into a room. Manually reversible fans are removed from window frames and turned around to reverse airflow. Electrically reversible fans, by contrast, change airflow direction through a switch.
Powerful window fans are capable of cooling spaces the size of the average house, and some are designed with equipment that allows fans to be installed in closed windows. Certain twin window fan models feature two fans operating side by side with panels that can be adjusted to accommodate various window sizes and are designed for more easy installation.