The decision to use whole house ventilation is typically motivated by concerns that natural ventilation won’t provide adequate air quality, even with source control by spot ventilation.

Whole house ventilation systems provide controlled, uniform ventilation throughout a house. These systems use one or more fans and duct systems to exhaust stale air out of the house and/or to supply fresh air to the house.

There are four types of systems:

• Exhaust ventilation systems
  Force inside air out of a home.
• Supply ventilation systems
  Force outside air into the home.
• Balanced ventilation systems
  Force equal amounts quantities of air into and out of the home.
• Energy recovery ventilation systems
  Transfer heat from incoming or outgoing air to minimize energy loss.

Information courtesy of EERE