Significant R&D work has been on going in the development of integrated software environments that support building energy simulation. Software interfaces have been developed in both academic and industrial settings that support an integrated approach to the development of building energy simulation models. However, software interfaces developed to date lack in the depth with regard to HVAC systems information and the ability to offer simplified generic models for a range of known building types, activities, HVAC systems etc. This paper describes an integrated software environment that supports the seamless integration of all aspects of a building required to develop and perform black box dynamic building energy simulation with a particular emphasis on the Heating Ventilation and Air Conditioning (HVAC) components and systems to support proposed EU Directive 2002/91/EC and its associated the asset rating process.