the PHPP methodology
It is essential to realise that a passivhaus building is much more than the sum of it's parts: at the core of the design of any passivhaus is the Passive House Planning Package. The PHPP document is a complex set of inter-related Excel spreadsheets, into which key information about the construction of the building and it's geographical location are entered. This then enables calculations to be performed which indicate how the building will perform in reality from an energy balance perspective.
The PHPP has been developed over the last 15 years using data from monitored built examples in order to inform and improve the accuracy of the results. This ensures a level of accuracy in the energy balance that the PHI state is +/- 0.5kWh!
It can also be a very useful design tool and should be used from an early stage in the design process to help establish certain key decisions, from the orientation and position of the building on the site to requirements for shading from the sun, all of which significantly effect the final performance and energy consumption of the building.
PHPP versus SAP
SAP, or the Standard Assessment Procedure, is the methodology used in the Building Warrant / Building Control process to demonstrate compliance with the Technical Standards. There are several key differences between the two methodologies in terms of the data entered and the consequential accuracy of the results, with the PHPP being substantially more accurate in predicting performance.