|EPA Indoor AirPLUS|
Prior to the advent of air-conditioning, occupants opened windows and doors for ventilation. Even after AC became a standard option, most homes were poorly insulated and "leaky". As energy costs have risen in recent years, increased insulation and tighter construction techniques have changed the rules as they apply to the building shell and mechanical systems. Modern homes need a controlled mechanical ventilation system and in many cases should also include an independent source of dehumidification. Standard air-conditioning systems will likely not be adequate.