Radon is the largest source of risk to human health caused by an indoor pollutant, at least in the industrial countries. Subslab Ventilation (SSV) is one of the most effective and common methods of reducing indoor Rn concentrations in houses with a basement. In this paper, we first quantify the impact of this technique on the air exchange rate, through numerical modeling of a prototype house with basement for a range of permeabilities of soil and subslab aggregate and various sizes of the cracks in the basement floor.

Due to the complexity in describing the simultaneous effects of a number of factors that influence the climate of an attic space it has proven to be difficult to make simulations of it. This report deals with the problem of using different computer programs for ventilation, heat andmoisture balance in an integrated way so that a proper description of the expected attic climate can be achieved. A general overview of attic space climate and the factors affecting it will be given and it will be described how the simulation packet works.

Besides the hygienic aspect, also the aspect of energy saving of heating residential buildings is very important. This is only possible by mechanical ventilation with heat recovery. This paper describes a part of the large variety of systems, which are nowadays available on themarket. The main difference of these systems are: * single room unit/decentral unit and * central unit for one dwelling or a single family building.

By means of parametric analyses, the paper describes how the "constantness" of a Constant Air Volume system is affected by temperature differences resulting from heat load variations or otherwise. Several design related parameters are considered. The paper starts with the background, then an outline of the (simulation based) approach, and how calculations were performed. Results are shown with respect to consequences for volume flow rates and for energy consumption.

The ventilation rate in a building depends on many things, one of which is the air temperature. The air temperature in turn depends in part on the ventilation rate. The effects of this relationship are generally overlooked in both thermal and ventilation models. To study this effect a model has been developed which integrates the models GAINE and SILONA developed at CSTB. This allows the prediction of the natural ventilation rates caused by the actual temperatures in the building.

This report presents the results from the registration throughout a month of relative humidity, temperature and outdoor air exchange as well as the concentration of carbon dioxide in each room of an inhabited single family house, in which all rooms are ventilated by a mechanical balanced ventilation system with variable air volume. The outdoor air rate is controlled by the relative humidity, which is kept on a value adequate to reduce the living conditions for house dust mites and prevent condensation on the indoor surfaces of the building.

Draughts due to air inlets are one of the problems to be solved for improving the global performance of mechanical ventilation systems. The CSTB full scale test cell "EREDIS" has been used to quantify draughts risks due to air inlets by measuring air temperatures and velocities with known boundaries of wall temperatures and fresh air. The results allow to improve the design of these inlets and to give advices for a better use in residential buildings. Works are now going on for comparing the experimental results to the ones calculated with a CFD code.

For more than 20 years, energy recovery systems have been operated successfully in European countries in comfort and industrial ventilation systems in order to reduce the heating and cooling capacity as well as to reduce the annual energy consumption for the treatment of supply air. By 1991 the total heating capacity of all installed energy recovery systems in Europe was about 60.000 MW and the equivalent of the annual energy savings was about 10 million tons of oil.

The new building and HVAC technology was used when an EBES multistorey residential building was built in Helsinki. In the EBES system the building structures are used as an installation space for the heating, piping, ventilation and electrical systems. Building structures are also used as a storage for heating and cooling energy. The main objectives of the overall EBES system are to improve the indoor air quality and energy economy and at the same time to improve the quality of the construction process and reduce costs.

Air extraction in the kitchen is an essential element in all ventilation strategies for dwellings. This can be done by natural ventilation or mechanical extraction. In practice, the use of mechanical kitchen hoods is very common in Belgium. As part of a research carried out for the Belgian IWONL/JRSIA, the laboratory for Hygrothermics and Indoor Climate of BBRI carried out measurements to evaluate the efficiency of kitchen hoods. The test procedure applied at BBRI is a mix-up of two existing standards.