Last edited 25 Nov 2020


The term 'hygrothermal' refers to the movement of heat and moisture through buildings.

Repeated wetting, drying, freezing and thawing of the fabric of a building can cause problems such as damp, condensation, mould growth and loss of thermal performance, and may even result in premature failure.

Computer-based hygrothermal modelling simulates the movement of heat and moisture, generating information relating to temperature, water content and relative humidity within multi-layer building elements.

Buildings can be affected by water through a number of mechanisms, including:

By simulating the performance of building assemblies, the risks of problems associated with these mechanisms can be evaluated and minimised. By understanding risks such as condensation, moisture entrapment, fungal growth, material degradation, and so on, the correct balance between heat and moisture can be achieved.

Physical testing may also be used to test the performance of materials or assemblies under a range of hygrothermal conditions.

NB Energy Efficiency and Historic Buildings, How to Improve Energy Efficiency, Published by Historic England in 2018, defines hygrothermal behaviour as: ‘…the movement of heat and moisture through buildings. Permeable materials tend to be hygroscopic because of the reduction in vapour pressure in the pores that occurs as a result of condensation, capillarity and salt action.’

[edit] Related articles on Designing Buildings Wiki


Designing Buildings Anywhere

Get the Firefox add-on to access 20,000 definitions direct from any website

Find out more Accept cookies and
don't show me this again