1. A ventilation system for use in ventilating a building or structure, comprising: a ventilation unit; a controller configured to control the ventilation unit; and a controller interface configured to accept one or more input parameters corresponding to a direct physical parameter of the building or structure, wherein said one or more input parameters includes an area input parameter and/or a number of bedrooms input parameter; and wherein said one or more input parameters further includes one or more parameters selected from the group of a ventilation airflow rate input parameter, a ventilation per room input parameter, a type of room input parameter, an outgoing airflow rate input parameter, a type of rooms input parameter, a number of rooms input parameter, a number of zones input parameter, a number of occupants input parameter, a leakage input parameter, a type of windows input parameter, a floor type input parameter, an environmental input parameter, a location input parameter, an elevation input parameter, an HVAC equipment type input parameter, an HVAC equipment location input parameter, an installed IAQ components input parameter, a type of IAQ component input parameter, an IAQ component capacity input parameter, a filter input parameter, and a UV lamp input parameter.