Fan blades and propellers are replaced as they become old or damaged. Fan blades that are bent or pitted have an impact on system performance and can lead to motor wear and undesired noise. When motors are replaced, they are frequently replaced as well to ensure that the blades are balanced and functioning properly. Aluminum fan blades are light and durable, making them ideal for usage in hot and humid environments. In HVAC condensers, condenser fan blades are used to replace worn or damaged blades. The fan blade is connected to the motor driving shaft via condenser propeller hubs. For usage in hostile settings, plastic fan blades are lightweight and corrosion resistant. Tube axial fan blades move air via ducts with low pressure and low air flow.