balanced ventilation

The measurement of particulate matter (PM) in rooms has gained interest in the last decade. However, the sensors that are currently used are intended for use in still standing air and cannot be applied to ventilation ducts with a typical velocity up to a couple of meters per second. Therefore, a prototype of a measurement module for particulate matter has been developed for use in ducts of ventilation systems. To the author’s knowledge, this has not been done before.

Measurements of the installed base of balanced ventilation systems in houses often show that optimal performance is not achieved. The installed base however, is a mix of various generations of units that have been developed over the years, starting in 1980. As a result, energy benefit and perceived comfort for residents is underestimated. Since 2015, improved knowledge has led to new technologies that have been implemented in the newest generation balanced ventilation units.

A balanced ventilation system can be combined with an air-to-air heat pump. Such system combines the refreshment of the air in a house with heating and cooling of the fresh air in order to influence the indoor conditions like temperature and humidity. Depending on the season in the year, various modes are used to deliver fresh air and condition the incoming air to the desired levels.  

The outdoor climate is changing and the airtightness and insulation levels of residential buildings are improving. During the warmer season this can lead to overheating problems, especially when the house is situated in urban areas. In order to reduce overheating problems, ventilative cooling can be used to keep the indoor conditions at a comfortable level. Natural ventilation is not always a feasible solution, for the risk of burglary, and when the outdoor temperatures are not suitable for cooling the house, for instance in urban heat islands. 

The differences between extract ventilation and balanced ventilation are subject of many discussions in sales markets where both solutions have their share. Often, the differences are marked in terms of energy, because balanced ventilation is normally accompanied by heat recovery. But there is another difference in terms of the ventilation effectiveness of the system.This document reports experiments in a scale model of a house showing the difference between extract ventilation and balanced ventilation in ventilation effectiveness, and therefore in achievable indoor air quality.

As a consequence of the energy and environmental issues, it is necessary to reduce the energy consumption of buildings. So, the air tightness of building envelopes is being improved and the air change rate due to infiltration is decreasing. It is then even more important than in the past that the buildings are equipped with well designed and working ventilation systems in order that the air renewal within buildings is ensured. In this context, the market of balanced ventilation systems with heat recovery for dwellings is growing. 

The efficiency of air-to-air heat recovery ventilation units is of great importance for EP calculations (energy performance of buildings) throughout Europe. Efficiencies compared on a reliable basis are also crucial for contractors and installers of such systems.

Discusses commercial Scandinavian balanced ventilation.