This project aims to demonstrate via a refurbishing operation, how a mechanical ventilation system can both provide a good indoor air quality and limit the energy consumption due to air renewal. The field of this operation concerns the improvement of indoor air quality for sensitive people as young children in classrooms, associated to a rational use of energy by the ventilation systems.

The present paper presents the results of the energy and environmental evaluation of ten school buildings in the Greater Athens Area. The research included measurements of the indoor air quality, evaluation of the situation of the building envelope, recording of energy and ventilation systems and generally all the systems that influence the energy output of the school buildings. Experimental investigations were performed in ten different schools and the concentration levels of CO2, CO and VOCs were measured.

Ventilation in buildings is necessary first for hygienic reasons and also to preserve the building structure. This is more essential, today, because the buildings are more and more airtight, mainly due to energy regulations. It is also evident that air renewal energy losses and fan consumption become more and more important in relation with the total energy consumption of buildings. Nevertheless, many defaults are encountered on installed ventilation systems. It seems necessary to check the installations, at the starting up and regularly in time, and not only when the problems occur.

Industry-wide methods of assessing duct leakage are based on duct pressurization tests, and focus on highpressure ducts. Even though low pressure ducts can be a large fraction of the system and tend to be leaky, few guidelines or construction specifications require testing these ducts. We report here on the measured leakage flows from ten large commercial duct systems at operating conditions: three had low leakage (less than 5% of duct inlet flow), and seven had substantial leakage (9 to 26%).

The increasing concern on energy conservation in buildings and the increasing insulation level of buildings, lead to the introduction of limits for building airtightness, to minimize building heat losses. In some countries the recommended limits are very strict and could be difficult achieved with standard construction practices. Usually the limits are established according construction (best) practices and in some countries it takes in account the building type, ventilation system and weather. Usually those limits dont take in account the air flow rate for background ventilation.

Studies on buildings’ airtightness have shown that several issues can arise from uncontrolled airflow leakages in buildings (e.g., higher energy cost, thermal comfort and health of occupants, building components and equipment preservation). The new French

In 1998, Persily published a review of commercial and institutional building airtightness data that found significant levels of air leakage and debunked the myth of the airtight commercial building. This paper updates the earlier analysis for the United States by including data from over 100 additional buildings. The average airtightness of 28.4 m3/hm2 at 75 Pa is essentially the same as reported by Persily in 1998. This average airtightness is in the same range as that reported for typical U.S.

This article describes five blower door measurements – each made with a different objective – carried out on large buildings. Proof of air tightness is required to guarantee the operational capability of ventilation systems or to enable fire protection by

This study investigates numerically the occurrence and duration of higher relative humidities in a cold attic space, which are a consequence of excessive moisture supply from ventilating the attic and from air infiltration from inside the dwelling. Hygrothermal states of the attic air zone and the adjacent construction elements are calculated by a whole building heat, air and moisture simulation tool. Airflows to the attic are determined by taking into account the total distribution of pressure around and inside a building.

Building materials and furnishing used in contact with indoor air have some effect to moderate the variations of indoor humidity in occupied buildings. Very low humidity can be alleviated in winter, as well as can high indoor humidity in summer and during high occupancy loads. Thus, materials can possibly be used as a passive means of establishing indoor climatic conditions, which are comfortable for human occupancy. But so far there has been a lack of a standardized figure to characterize the moisture buffering ability of materials.