Whole Building Heat, Air and Moisture Response (MOIST-EN)

Completed (2003 - 2007)


The project aimed to acquire a better knowledge of whole-building heat, air and moisture balance and its effects on the indoor environment, on energy consumption for heating, cooling, air humidification and air drying, and on the envelope's durability. The research follows on from 'Condensation and Energy' (Annex 14), 'Heat, Air and Moisture Transport in Insulated Envelope Parts' (Annex 24) and 'Integral Building Envelope Performance Assessment' (Annex 32).

The project had two main objectives:

A detailed exploration of the complex physics involved in whole building heat, air and moisture response (HAM-response). This included basic research, a further development of existing and new models, measurement of the moisture storage function of materials, measurement of the air permeance of envelope parts as built, mock up testing, field testing and validation by inter-comparison of models through common exercises and confrontation with measured data.
This first objective aimed to foster a basic understanding of transient moisture storage in different finishing materials and moisture exchange with the indoor air. For this purpose material storage properties were measured. This should help develop numerical models and backup experiments that link the heat and moisture storage and HAM-transfer in enclosures to the performance of the building and the HVAC system. Mock-up and field measurements have to prove the effectiveness of moisture storage under different weather conditions (cold, warm and dry, warm and humid and maritime).

An analysis of the effects of the whole building HAM-response on comfort, enclosure durability and energy consumption. A literature review should increase the awareness for these effects. Simultaneously, measures will be studied to moderate possible negative impacts on comfort, enclosure durability and energy consumption, with air-tightness, moisture management, thermal insulation and humidity storage as some of the measures projected.

The research work was divided into four sections:

  • Modelling principles and common exercises
  • Experimental investigations
  • Boundary conditions
  • Long term performance and technology transfer

Operating Agent

Prof Hugo Hens
K.U. Leuven
Department of Civil Engineering
Laboratory of Building Physics
Kasteelpark Arenberg, 51
B-3001 Leuven
Tel: +32 16 32 13 44


Austria, Canada, Belgium, Brazil, Denmark, Estonia, Finland, France, Germany, Israel, Japan, Netherlands, Norway, Portugal, Sweden, Slovakia, Spain, Switzerland, UK, USA


  • Project Summary Report - Annex 41 (PDF 2.54MB) Edit Publication
    Author: Hugo S.L.C. Hens
  • Volume 4: Applications: Indoor Environment, Energy, Durability Edit Publication
    Author: Andreas Holm
  • Volume 3: Boundary Conditions and Whole Building HAM Analysis Edit Publication
    Author: Kumar Kumaran, Chris Sanders
  • Volume 2: Experimental Analysis of Moisture Buffering Edit Publication
    Author: Staf Roels
  • Volume 1: Modelling Principles and Common Exercises Edit Publication
    Author: Monika Woloszyn and Carsten Rode