Using an AC fan, with this speed control you have intermittent and continuous ventilation.
The sensor mounts into the fan with two pre-drilled holes in a standard receptacle.
 

• Accessible speed adjustment
• Simple plug fits into fan housing
• Can be installed with a new or existing fan
• Allows for continuous adjustable speed control as per Ashrae 62.2, with high speed override

Compatible Fans (sold separately):