At architectural studio Apxe, we use the PHPP — Passive House Planning Package as our main tool for energy modelling and Passive House design. The Passivhaus Institut developed PHPP to support the design of energy-efficient new buildings and retrofits. It helps us assess energy performance during the design process and understand how each decision affects the building as a whole.
What we calculate with PHPP
We enter data on the building’s geometry and orientation, the areas and properties of its walls, roof and floor, its windows and external doors, shading, thermal bridges and building services. We also account for the local climate and other factors that influence the energy balance.
PHPP allows us to calculate and assess:
- annual heating demand and peak heating load;
- cooling demand and the risk of summer overheating;
- the building’s primary energy demand;
- the expected energy generation from renewable sources.
These results let us compare design options and assess how changes to the building’s shape, orientation, glazing, insulation, shading and building services affect its energy performance. We can identify issues such as overheating risk during the design stage and work towards a balanced solution for comfort, energy efficiency and investment cost.
PHPP informs the design from the start
We begin energy modelling with the first design options and update the calculations as the project develops. When we change a key element—for example, the size and position of windows, insulation thickness or ventilation performance—we check how that change affects the overall energy balance. PHPP therefore informs specific design decisions throughout the project rather than serving only as a final check.
The model treats the building as a system. We coordinate information from the architectural, structural and building services designs instead of assessing each component in isolation. We develop the energy model alongside the detailed design, thermal bridge analysis and construction details.
PHPP supports design decisions and the assessment of energy performance, but it does not replace construction quality control or on-site testing. For example, we verify airtightness with a Blower Door test, not with a PHPP calculation.
Practical experience and professional qualification
Architect Georgi Nikolov holds the Certified European Passive House Designer qualification. The training and examinations place strong emphasis on practical PHPP work and on applying energy modelling to real projects.
At architectural studio APXE, we combine PHPP with our experience in the design and construction of Passive House buildings. This allows us to connect the calculations with specific architectural, structural and building services solutions, and to track the energy balance from the early concept through to project completion.
Passive House Planning Package (PHPP 2007) – verification sheet of Plus energy house in Kladnica