Following calculations of potential energy savings, several types of earth-air heat exchangers have been coupled to buildings in novel concepts for passive heating and cooling of ventilation air. For the first time this technology was used in the Belgian climate. In a first case one short plastic tube is coupled to the HVAC system of an office building, to preheat/precool the fresh ventilation air. Measurements are presented on this system and it is shown that performance could have been improved by more concern during the design stage.

Air filters may be used to reduce indoor airborne concentration which is one of the main indoor air pollutants. Air filters performances have to be measured in order to be able to select the right product for a given application. But differences do exist between laboratory and field filter test results and HVAC installations have to be controlled regularly. EUROVENT 4/10 recommendation describes guidelines for the evaluation of the perpromances of HVAC air filters according to particle size in an installation.

This paper summarizes part of the work held at ENTPE within the framework of the IEA Annex 35 project. The aim of the work is to develop and experimentally evaluate control strategies for hybrid ventilation systems to provide comfortable indoor environment and good air quality by combining the best aspect of natural and mechanical ventilation. To reach this target and asses the physical model elaborated in this project, a test cell "HYBCELL" has been designed within the laboratory.

A potential conflict may exist between energy saving and good indoor climate. The present project is phase 2 of a 5-year research programme consisting of four phases, the objective of which was to develop energy efficient ventilation strategies that will provide both healthy and comfortable indoor climate and reduced energy consumption when compared to present standard.

DCV systems have proved to be energy saving with correct IAQ in previous studies. In order to achieve correct performance, these systems must be properly designed and tested. The purpose of this study is to identify the possibility of using presence sensors based on movement detection to evaluate the number of people present in a room, and also gather some more information about the real occupation rate of meeting rooms. For that, an experiment in several kinds of meeting rooms, located in different buildings and having different uses has been run.

The NEN 5128 "Energy performance of dwellings and residential buildings- Determination method" [1] describes a procedure to calculate the energy performance coefficient EPC. The requirements are given in the Dutch Building Decree [2]. The energy performance is expressed as an Energy Performance Characteristic (EPC). In this EPC procedure ventilation and air tightness play an important role. This paper describes the role of ventilation and air tightness in the Energy Performance Standard. Moreover it gives the alternative way of the so called equivalence principle.

The airtightness performances of buildings and ventilation systems can have a major impact on the indoor climate (IAQ, thermal comfort,...) and on the energy performance. Measurement results for Belgian buildings clearly show that the airtightness is often moderate to very poor. As part of the proposed energy performance legislation for the Flemish Region, it is envisaged to pay attention to the airtightness of buildings and ductwork. In the first part of the paper, results found for Belgian buildings and systems are briefly presented and discussed.

Ventilation plays an important role in the RT 2000 regulation. The ventilation system is of course taken into account, but also the building envelope airtigthness on which this paper focuses.

We investigate the airtightness of 12 French non-residential buildings, by means of experimental fan-depressurization tests. For this study, 12 recent large (volume > 500 m 3 ) buildings have been chosen according to the construction structure and the activity. Four categories of buildings have been selected : hotels, schools, offices and polyvalent halls. We assessed the air leakage rate of each building, with a fan-depressurization equipment, following the recommendations of the international norm project ISO 9972.

Most dwellings in the United States are ventilated primarily through leaks in the building shell (i.e., infiltration) rather than by whole-house mechanical ventilation systems. Consequently, quantification of envelope air-tightness is critical to determining how much energy is being lost through infiltration and how much infiltration is contributing toward ventilation requirements. Envelope air tightness and air leakage can be determined from fan pressurization measurements with a Blower Door. Tens of thousands of unique fan pressurization measurements have been made of U.S.