People turn on their bathroom exhaust fans when it's hot outside for a specific reason: to remove excess heat and humidity from the bathroom. The primary purpose of a bathroom exhaust fan is to eliminate moisture and odors that accumulate during activities such as showering or bathing.
During hot weather, humidity levels tend to be higher due to increased perspiration and the warm outdoor air. When someone takes a hot shower or bath, the bathroom environment becomes even more humid, which can be uncomfortable and contribute to a feeling of stuffiness.
By turning on the exhaust fan, the humid air inside the bathroom is drawn out and expelled to the outside. This helps to reduce the overall humidity in the bathroom, making it feel cooler and more comfortable. Additionally, removing excess moisture can help prevent the growth of mold and mildew, which thrive in damp environments and can exacerbate indoor air quality issues.
The exhaust fan also helps to circulate the air, promoting better ventilation and aiding in the process of cooling down the room by allowing hot, stale air to escape and fresh, cooler air to enter from other parts of the house.
It's important to note that while bathroom exhaust fans can help reduce humidity and improve comfort during hot weather, they should not be used as a substitute for proper air conditioning or cooling methods in the rest of the home. An exhaust fan can only provide localized relief in the bathroom area, and for overall comfort, it's best to have a well-maintained and properly functioning cooling system that covers the entire living space.