Measurements of air change rates, carbon dioxide concentrations, room air temperatures and relative room air humidities in bedrooms of five well tightened dwellings were carried out in October 1989. With the results of the measurements and also based on simulation calculations, recommendations for an optimal window opening behaviour in bedrooms with the intention of saving energy and of providing sufficient indoor air quality were made.

This paper presents measuring results from experiments with integrated air heating and ventilation system in airtight well-insulated buildings in Stockholm (The Stockholm Project) .

The paper presents results of ventilation characteristics of a lecture/seminar room obtained by various door-window opening combinations and positions, and the level of comfort and air quality resulted by the given window-ventilating modes. Applying statistical methods, formulae of air change rate for the test room under it's normal operating condition i.e. when all window and external door are shut and when particular windows are opened is also presented and graphs in relation to dominancy factors such as wind and buoyancy effects, are given.

As part of the IEA Research Program Annex 18 "Demand Controlled Ventilating Systems" were tested in a one-family testhouse in relating to energy and ventilating specific aspects. The investigation should show whether demand controlled systems are useful in dwellings or not. Following items were checked: * Infiltration characteristics of the testhouse * Ventilation characteristics of different systems like temperature distribution, air movement, ventilating efficiency, air exchange and air quality.

The controllability of room air temperature in different heating systems connected to demand controlled ventilation systems was studied. Studied ventilation systems were exhaust, supply and exhaust and a system with exhaust and an individual supply to each apartment. Studies were made using PIPNET-simulation program package. It is designed to allow detailed simulation of entire building systems: the building shell, heating and ventilating plant and the dynamic thermal interactions among the subsystems. First single zone calculations were performed.

In this paper the required ventilation air flow rates in residences with different pollutant loads are considered. The calculative study was carried out by using the load data presented in the literature. The results of the study were applied in the development and dimensioning of demand controlled ventilation systems. The first stage of calculations was to determined the required ventilation air flow rates (range) with different loads for each type of rooms separately. In the analysis of required ventilation air flow rates due to material emissions, the Monte Carlo-method was applied.

The ventilation system described here combines a central air shaft in the hall area with a mechanical waste air extraction system in the bathroom and in the kitchen. If there is a large amount of moisture in the dwelling, the volumetric flow of thewaste air fans is increased, the increase being controlled by means of hygrostats. This ventilation system ensures adequate ventilation of the dwelling. In dwellings without a supply air shaft, this hardly applies any more with the installation of windows with very low joint permeability.

Turbulent flow fields of velocity and diffusion in several types of mechanically ventilated rooms are precisely analyzed both by model experiment and by numerical simulation based on the k-s two-equation turbulence model. The detailed analyses of contaminant diffusion by simulation make it possible to comprehend clearly the structures of velocity and diffusion fields in rooms. The flow fields in such rooms, as analyzed here, are mainly characterized by the inflow jet and the rising streams around it.

On basis of several case studies into the ventilation behaviour in dwellings in the Netherlands, it is possible to answer the question whether the type of ventilation device influences the behaviour of the occupants during mild winter periods (5 Deg C).The dwellings are discerned in three types: * those with natural ventilation through passive stacks only; * those with mechanical exhaust ventilation provisions; * those with balanced mechanical ventilation provisions.

The paper summarises the IEA, Executive Committee on Energy Conservation in Buildings and Community Systems, Annex 14 work on Condensation and Energy, a joint research effort of the Federal Republic of Germany, Italy, the United Kingdom, the Netherlands and Belgium, finished end of march 1990. First the complex relations between mould+ surface condensation, the outside climate, the building fabric, inhabitants behaviour and energy conservation are discussed. Then follows a short overview of the Annex achievements with mayor emphasis on the guidelines and practice results.