The Powerform Controls range of Current Sensors are designed to go inline with a load and switch relay contacts when the current goes over a threshold. The relay contacts can be used for anything - as an input to a run-on timer, driving a booster fan or interfacing with a BMS (Building Management System).
The Current Sensors are commonly used with Dryers and Rangehoods. They allow an automatic non-invasive way to switch on a ventilation/booster fan when the device is being used.
For apartment laundries this means the hot air can be automatically extracted from a laundry cupboard/room when the dryer is used - reducing the chances that the room will go mouldy from all the hot/moist air. Automatically extracting the hot moist air also improves the dryer performance. And because it is automatic the resident doesn't have to remember to turn it on or off - no more leaving the light on all day because the dryer was running when they left for work!
For rangehoods the Current Sensors can detect* the difference between the canopy lights & fan, only switching on when the fan is used. This can then turn on a booster fan or open a damper into a central riser, without modifying the rangehood or requiring the user to remember to turn something on or off.
* This does depend on the relative current draw of the lights & fan but with all rangehoods we've seen so far it has been possible