The Passive House Institute plans to introduce new building categories that rate a building's energy production in addition to its energy demand. Called "Passive House Plus" and "Passive House Premium", these new categories will evaluate buildings based on how much energy they produce from renewable sources like solar panels compared to how much energy they consume. The new categories aim to provide guidance for buildings that produce more energy than they use. Details on the new Passive House classes will be presented at the International Passive House Conference in April 2014. The categories calculate energy production relative to factors like the building type and area to provide a standardized evaluation.