Ventilation in low energy residences – a survey on code requirements, implementation barriers and operational challenges from seven European countries

Abstract

This paper reports the results of an interview survey conducted among different stakeholders involved in design, installation and operation of residential ventilation in seven European countries. In total 44 interviews were performed. The results provide a valuable snapshot of current practices and insights into potential barriers and challenges regarding installation of mechanical ventilation in low-energy residences to maintain high indoor air quality (IAQ). The results show that mechanical ventilation with heat recovery is becoming a common choice in new low energy residences in Europe. However, there are countries that apply airing or other types of ventilation such as mechanical exhaust or natural ventilation due to tradition, national legislation, climatic conditions and/or cost reasons. Demand-controlled ventilation (DCV) is often allowed or even recommended in standards, but rarely implemented in practice, except for exhaust-only humidity-based DCV in France and Belgium. The main barriers against mechanical ventilation seem to be high capital cost, space requirements and duct routing. The respondents commonly reported problems resulting from poor construction, lack of commissioning and/or maintenance. The main needs identified in the survey were: more legislative pushes including more flexibility in legislation, a coordinated approach to energy efficiency and IAQ, and control mechanisms to ensure good implementation and operation.

Bedroom ventilation: Review of existing evidence and current standards

“…In the literature, there is a limited number of reviews of some ventilation standards [20,21]. A broader review of international ventilation standards like ASHRAE and CEN and fifteen countryspecific standards in this paper showed that there is general guidance towards the provision of ventilation in the design of residential buildings.…”

Role of ventilation on the transmission of viruses in buildings, from a single zone to a multizone approach

“…In this context, more attention is given to the ventilation design and on-site implementation, [39][40][41][42][43] and ventilation systems are becoming more energy efficient with balanced systems including heat recovery or smart systems with variable airflows. [44][45][46] The current COVID-19 epidemic has highlighted another building ventilation issue: prevention of disease spread. The literature review analyzing air-transported viruses points out a lack of data to push work forward from theory to prevention practices, particularly regarding which ventilation conditions have a strong impact on the environmental contexts that favor (or hamper) the survival…”

“…The building energy performance perspective requires efforts to rethink ventilation airflows because of their impact on thermal losses. In this context, more attention is given to the ventilation design and on‐site implementation, 39–43 and ventilation systems are becoming more energy efficient with balanced systems including heat recovery or smart systems with variable airflows 44–46 …”

Design of residential ventilation systems using performance-based evaluation of Indoor Air Quality: application to a Danish study case

“…The two most important are: 1. Building regulations do not always allow decreasing airflows below certain minimum thresholds, for example a minimum background ventilation rate 0.3 l/s.m -2 in the Danish building code (Zukowska et al 2020); 2. The requirements are prescriptive, based on constant airflows or constant air change rates, while for strategies with varying airflows a performance-based approach expressing the consequence of the control strategy expressed as suitable IAQ indicators is needed to exploite their potential.…”