The purpose of this study was to carry out a mathematical modelling analysis of the effect of indoor pollutant source strengths and ventilation rates on the concentration of pollutants. These concentrations are then compared to various human exposure limits and targets. The modelling was carried out for a variety of ages of residential detached housing for a range of Canadian climatic conditions. Although a literature search was performed, pollutant source strength data for housing was not generally available.

The occupant's behavior with respect to window opening may greatly affect the ventilation system, the energy consumption orland the indoor air quality. In order to quantify the magnitude of opening times, many surveys have focused on climatic parameters and concluded to the temporal correlation between the timelength of opening and the outside temperature or the solar irradiation. In this paper, we study the influence of sociological and technical parameters on the average time of opening during the winter.

This paper reports the results of humidity and ventilation measurements in occupied residential buildings to study the effect of airborne moisture movement on condensation risks. The dwellings have been fitted with a cooker hood and an extractor fan (both with variable speed control) in the kitchen and an extractor fan in the bathroom.

Ventilation systems in dwellings should not only maintain the quality of the air, in other words limit pollutant concentration whatever the origin, but protect the structure, that is, limit condensation and the storage of excessive humidity in existing materials. Domestic ventilation represents a significant element of energy loss. It is a function that should be provided at minimum cost in terms of energy and therefore be directly dependent on fresh air requirements. Hence the introduction on the market af socalled hygro-adjustable ventilation systems.

Modern one-family houses in Scandinavia built before 1980 are often naturally ventilated and heated by electric baseboard heaters. The overall supply of fresh air is often inadequate during the heating season in many of these houses. Long periods of time individual rooms might get too little fresh air. The performance of a natural ventilation system is very much dependant upon the overall airtightness and the distribution of the airtightness of the building and the weather.

A cross-flow polymer membrane enthalpy exchanger has been designed which provides both heat recovery and moisture dissipation in the ventilation of living spaces. The exchanger is of benefit in providing fresh air during both cooling and heating seasons with minimum loss of energy. A prototype of the enthalpy exchanger has been constructed and tested. The air leakage of the equipment has been found to be negligible; that is, the two air streams are indeed non-mixing.

This paper investigates quantitatively the energy conservation achieved by balanced ventilation with heat recovery and upstream ground heat exchanger. The investigations were conducted on an occupied single-family house equipped with such a balanced ventilation system. The heat recovery unit of this system consists of a plate-type heatexchanger with a downstream small air-to-air heat pump. In addition this house is equipped with a ground heat exchanger.

A prototype of a low cost, low energy office building was built using a new Finnish component system building technology. Thanks to the energy efficient windows, the thermal insulation of the building envelope and the demand-controlled variable outdoor air flow HVAC system with heat recovery and energy-storing structures, the need for heating and cooling energy has been reduced to such a level that a low energy office can be cooled with outdoor air and with the aid of a heat recovery device. The building is kept warm with the support of its own operations almost throughout the year.

A heat recovery system reclaims heat from outgoing stale air, supplying it to incoming fresh air. The energy benefit is greatest if it supplies all the fresh air to the house and none enters via uncontrolled openings, hence ventilation heat recovery (VWR). A sunspace (or conservatory) attached to a dwelling will almost always be at some temperature above ambient. Heat losses by conduction through the adjacent building fabric and ventilation losses via cracks will be reduced.

In well insulated buildings the ventilation heat is sometimes higher than the heat losses by transmission. For a air change rate of 0,8 per hour the specific heat flux must be calculated with 25 w/m², so heat recovery can save some energy. In all considerations the saving in the heating system must be compared with the additional energy for the fans, because this energy is of a higher quality. To optimize the heat recovery system, the different designs of the heat exchanger, the annual running hours and the annual hours for heat recovery must be taken into account.