Mechanical ventilators are extremely important for exhausting stale indoor air.

The two categories of ventilators include:

Local ventilators
Local ventilators exhaust locally produced humid air, odours, gases, and particles. Kitchen range hoods and bathroom exhaust fans are local ventilators. If you operate a workshop inside your home or garage and work with chemicals, you should install a local ventilator to remove harmful contaminants.

Whole-house ventilators
Whole-house ventilators continuously exhaust a home’s entire volume of stale indoor air. They also bring in an equal volume of fresh outside air. These ventilators can help to control humidity and dilute harmful gases (off-gases from insulation and press-wood furniture, carbon monoxide and other gases from cigarette smoke, etc.). Whole-house ventilators are generally sold as heat-recovery ventilators (HRVs) or energy-recovery ventilators (ERVs). Both types recover some of the energy you’ve put in to the air before it is exhausted outside.