Many residential green certification programs require that a home or apartment meet the ASHRAE 62.2 ventilation standard. The easiest way to accomplish this is by installing a continuous bathroom fan for an exhaust-only set up, but this is discouraged in humid areas. A supply-only system relies upon an intake duct into the HVAC return plenum, but adjusting the motors is rarely addressed by installers. A balanced system can use an energy recovery ventilator, but does an ERV really increase the energy efficiency of a house 10 to 15 percent? There are conflicting opinions in the industry about how much ventilation is actually needed.
Read the full article here: What is the Deal with Ventilation Requirements?