The motivating idea behind Passive House is centred on optimising all the energy relevant components such as the building carapace, the windows and doors, the ventilation, heating and hot water, and electricity supply. To facilitate this enhanced energy efficiency, these different areas of building need to be coordinated to achieve a high level of improved energy saving. The Passive House Planning Package (PHPP) is a tool used in this process, to dimension the components in a building design, and to verify these values. It’s a decisive procedure which can take a project from initial design concepts right through the project planning stages to implementation. PHPP can also be used to monitor and gauge a building’s actual fuel usage.