Used as a whole-house, exhaust-only or supply-only ventilation, depending on the climate (exhaust-only is not recommended in hot or humid climates, supply-only is not recommended in cold climates). Exhaust-only ventilation is placed in bathrooms, laundry rooms or other areas and connected together through the in-line fan, typically placed in the attic. Supply-only ventilation must be strategically placed to keep your home comfortable from the incoming, unconditioned air (alternately, air can be supplied to the return of a central HVAC system in most climates).
An in-line fan placed in the attic will be quieter when compared a fan located in a bathroom ceiling.
Dryer Vent Boosting
In larger homes or multi-family units, dryers must often be installed far from exterior vent outlets, requiring duct lengths that exceed manufacturer's recommendations, lowering dryer efficiency and allowing hazardous heat build-up. Some in-line booster fans are specially designed to maintain safe and effective dryer operation.
Indoor Air Quality, Fresh Air Injection and Building Pressurization
Buildings that are highly insulated and tightly sealed may require mechanical introduction of fresh air for ventilation and pressurization. In-line fans can be used in conjunction with HVAC systems for air supply, air purification, dehumidification or heat recovery.