An idea to build a demonstration house fitted with a hybrid ventilation system arose when Brno University of Technology joined the RESHYVENT project. There has not been much attention paid to the residential ventilation in the Czech Republic. Window airing and passive stack ventilation are still the most common ways of ventilation in residential buildings. In this context a decision was made to build a house equipped with a demand controlled hybrid ventilation system.

To get closer from comfort and energy levels of new buildings conciliating economical viability for the big retrofitting market : the challenge opens the way to the most innovative ventilation systems. In this context was born a new hybrid ventilation system mixing demand-controlled components and low pressure assistance fan. HR-VENT is an exceptional large-scale monitoring launched in France in the suburb of Paris in order to measure the effectiveness of this new system, as well as to improve the knowledge on the hybrid and standard natural ventilation.

The Dutch housing stock consists for about 70% of single family houses with an average N50 of about 7-9 ACH and for 30% of apartments with an average N50 of about 3-4 ACH.New single family houses are much more airtight. In the period 1970 to 2000 the air tightness increased to an N50 of about 3 - 4 ACH. Apartments have nowadays about the same or a slightly better air tightness then before 1970.Another trend is the downward tendency of occupant numbers per dwelling.

Hybrid ventilation is one promising approach to reduce energy consumption in office buildings. On the one hand, a minimum air change rate is supplied to the rooms, even if the windows are closed. On the other hand, the energy demand for ventilation can be reduced if natural forces (wind and buoyancy driven air flow) are used to ventilate the building. The user behaviour has an important but often unknown influence on the thermal building performance and the indoor climate. Thus, an accurate user model should be used in designing hybrid ventilation.

In this paper, the current situation of Portuguese residential buildings in terms of ventilation systems ispresented. The indoor air renewal is, normally, obtained by providing fresh air exclusively by air leakage of doors and windows and their occasional opening and exhausting the air through ducts placed in kitchens and bathrooms. A recent revision of the Portuguese standard NP 1037-1, concerning natural ventilation of dwellings, is studied and its influence upon heating energy consumption and indoor temperatures is reported.

COOLHOUSE demonstrates the use of passive cooling techniques in southern regions of Europe which are aimed at giving comfortable summer conditions in domestic scale buildings without using mechanical cooling systems. The project focussed on three sites, a private development of houses for sale in south west Portugal, an old peoples home in south France and a community centre in mid Italy. All are new buildings and were designed to provide cool internal conditions by passive means such as using solar shading and thermal mass, with the addition in all three cases of ground cooling pipes.

One of the major sources of problems in dwellings -if not the main source- is moisture, especially due to surface and interstitial condensation on walls and roofs. For this reason, it seems important to evaluate the current standardisation and reference documents dealing with moisture and eventually to develop new assessment methods. This is the goal of the Belgian project "Moisture problems in roofs", carried out by BBRI, KUL, RUG and W&K. The first step is to collect a large number of indoor climate measurements in recently built dwellings built.

This paper addresses the issue of the compliance of residential ventilation systems with building regulations. Because the French building code includes requirements on performance as well as on means, the approach adopted by the French government consists in checking both airflow rates and functional measures. This paper gives an overview of the methods used and analyses the results of tests performed on 260 building projects (multi-family buildings and grouped individual houses).

The paper presents the results of the analysis of the impact of various ventilation systems on indoor air quality and energy consumption, performed for a typical Polish elementary school that was built in 1970s. Simulations were made with the use of two computer codes: CONTAM W and ESP-r. A multizone model of the global capacity of 9464 m3 was performed. The model contained 17 classrooms and 10 additional rooms typical of such buildings.

A research project aimed at investigating IAQ and thermal, acoustic and visual comfort was carried out in Italian high school and university classrooms. The investigations were performed through field campaigns during regular lesson periods consisting of subjective surveys and measurements. This work focuses in analysing the results from the IAQ investigations at four high schools of Provincia di Torino during the heating period.