2 ms·Every rental I've had had one. That was eight units in total. We didn't get fancy rentals.by tomrod 3y agoEvery rental I've had had one. That was eight units in total. We didn't get fancy rentals.dangus 3y agoAre you sure it wasn’t a recirculating fan? How new was this building? Every rental I’ve lived in was built at least 50 years ago because I can’t afford a new luxury rental.tomrod 3y ago100%, as I would check for external venting. Ranged from 1890 to 2005.