English

Wind pressure and thermal forces are driving forces for pressure difference on the building envelope. In European and German standards infiltration is calculated using wind speed, temperature difference and wind pressure coefficients resulting from upstream and downstream flow on the building envelope. This long term measurements shall present measured pressure differences on the building envelope in comparison to those calculations

With lower air leakage in modern homes, ventilation of homes has become more important than ever before. It seems however that we are getting it very wrong. A lack of ventilation can cause building sickness, with degradation of the physical building and also poor air quality which has a big impact on the occupants themselves. Our statistics show that designers and contractors are still not getting it right, leaving us with a generation of poorly ventilated housing stock.

The objective of present work was to develop the metric that assess the performance of solutions securing high indoor air quality in low-energy (modern) residential buildings. This was achieved by summarizing data on the levels and types of gaseous pollutants and particulate matter in low-energy buildings and comparing them with the existing exposure limits for pollutants.

Because buildings are responsible for 40% of energy use and 36% of Greenhouse Gas (GHG) emissions in the EU, energy efficiency in buildings has become a priority to drastically reduce the energy use in buildings. Consequently, a number of policy measures have been implemented in European Member States to drive the market towards Nearly Zero-Energy Buildings, including the Energy Performance of Buildings Certificates (EPCs), which are the most visible instrument of the Energy Performance of Buildings Directive (EPBD).

There have been many new sensors introduced on the market claiming that they can perform accurate measurements of Indoor Air Quality. Many of them are low-cost sensors that can be applied at the mass scale. The subsequent question is what is and should be considered to be the metric of Indoor Air Quality. No consesus on this matter has yet been achieved. Few metrics have been proposed in the past including most known CO2 and TVOC concentrations but actually only CO2 concentration has been widely used in the applications related to built environment and HVAC.

Building airtightness tests have become very common in several countries, either to comply with minimum requirements of regulations or programmes, or to justify input values in calculation methods. This raises increasing concerns for the reliability of those tests.

There are four key sources of uncertainty in airtightness testing:

The European market for residential ventilation is highly driven by energy performance regulations. In new buildings the share of balanced ventilation with heat recovery is increasing as a result of more severe energy performance requirements (NZEB). The energy labeling for residential ventilation units and the ecodesign requirements for ventilation units may be drivers for a more wide-spread application of heat recovery ventilation in new buildings.

The first ASHRAE IAQ conference in 1986 was held “to review the latest research in indoor air pollution and provide missing current data for Standard 62” with the understanding that, “the indoor environment should minimize any impact on health and should be free of any impact on comfort, and control should minimize the use of energy.”1 Implicit in this statement is the belief that the performance measures needed to realize this goal could be defined in practical terms.