Passive Design Assistant

A software tool that demonstrates the principles of the passive thermal design of buildings.

Passive Design Assistant (PDA) is a software tool that demonstrates the principles of “passive” (non-mechanical) thermal design. This includes factors such as: insulation, solar gain, thermal mass, ventilation and climate.

PDA enables an assessment to be made of temperatures within a building operating in ‘free running’ (non-mechanical) mode or the demand for heating and cooling when the building is being operated in a mechanical mode.

PDA has a simple and intuitive user interface that enables the user to understand the influence of key parameters in a quick and easily accessible way. The software models a single room or space and uses an industry-standard calculation method (the CIBSE Simple dynamic model). Results are displayed clearly and respond to parameter changes instantly. The user can construct material build ups from a library of material types and input site-specific climate data.

The PDA software was developed by Arup working with the Mineral Products Association and AHMM architects with financial support from the UK Government’s Technology Strategy Board.

It is intended that the software is simple enough to be used by all those involved with or interested in the design of buildings. It can be used either for educative purposes or to inform early-stage design. It is recommended that more complex calculation methods be used for detailed design development.


Please return to this page periodically to check for the latest version of PDA. We are unable to offer support, however please report bugs or feedback to the developers by email


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Screenshot showing how the Passive Design Assistant software works