The predecessor to this Applications Manual, Building energy and environment modelling was published in 1998. Much has happened over the last two decades in the modelling fields, including computer power and software advances but, more significantly, those in the optimisation of building and system performance for energy reductions and the application of renewable energy technologies in building design and operation. The latter is compounded by rapidly evolving building regulations and strict compliance requirements towards the goal for zero carbon buildings (ZCB) in order to meet the CO2 reduction obligations of some countries. 
In that publication the task group aimed ‘to furnish guidance on the appropriate application of BEEM software, to promote good practice and offer reference material to support practicing engineers’. This aim is still evident in this new Applications Manual, although the present edition has been completely re-written and extends the application of building modelling to many areas that currently need to be properly addressed in building and system design.
With the emphasis on the energy performance of buildings and their systems in order to meet ever stricter building regulations, it has become a necessity to apply sophisticated, state-of-the art simulation tools to predict the performance of buildings as closely as possible to reality. As buildings are known to be complex engineering systems, the performance of which are influenced by a variety of internal mechanical and electrical systems in addition to occupants’ intervention and the external environment, recent advances in simulation tools have attempted to address this complex interaction to provide more comprehensive and detailed performance simulations.
This new AM11, Building performance modelling (BPM), has taken into consideration many of the real issues of simulating buildings and their systems whilst still focusing on compliance with building regulations and quality assurance issues. BPM covers the general concepts of energy and environmental modelling and in particular focuses on: quality assurance procedures, compliance with UK and some international building energy efficiency codes, thermal environment and energy, ventilation, lighting and plant modelling.
This Manual has been written by experts in a variety of building design and modelling software, from academia and engineering practices, providing their expert knowledge in the application of these tools to building and system designs. Many of those involved were also committee members of the CIBSE Building Simulation Group. The dedication and enthusiasm of these and other contributors has produced this very comprehensive manual that is hoped to provide the building design professionals with the knowledge and confidence for effectively applying different types of modelling software in their designs.