The type of maintenance needed for attic exhaust fans includes lubricating the oil ports every few years, cleaning the fan shutters that release hot air and washing the blades of the fan every few years to take care of unwanted build up. Exhaust fans don't need yearly maintenance.
Attic exhaust fans are most often used to cool down a home when the exterior air is cooler than a home's interior air. The fan siphons cooler air in through doors and windows, while forcing out hot air through the vents of the attic. Some fans are automatically switched on with a specific temperature. There are also models with activation switches that can be programmed to operate for a specific period of time.
While an attic exhaust fan is being used, the windows on the lower levels should be opened to help improve overall ventilation. If windows aren't opened while the exhaust fan is on, there's a chance that the exhaust given off the home's combustion appliances can be sucked into fan.
If an attic has soffit vents or isn't sealed very well from the remainder of the home, there's a chance that the exhaust fan may pull conditioned air into the attic. If this happens, more energy than necessary is used, and energy bills can increase.