Behind closed windows : an actor-centred analysis of barriers for the diffusion of energy efficient ventilation systems in residential buildings

Abstract

Reaching the climate goals for the building sector requires to improve insulation and to increase air tightness of buildings in order to minimize heat loss. To achieve these goals and to prevent risks to the health of occupants and damages to the building fabric due to insufficient removal of pollutants and humidity, broad implementation of Mechanical Ventilation and Heat Recovery (MVHR) systems is crucial. Comparable and up to date figures on the market penetration of MVHR systems across the EU are hardly available. However, figures point to only a small share of residential buildings being currently equipped with such systems (cf. Riviere et al. 2009). For the German building stock the figure is estimated to be below 5% (Händel 2011). The paper presents insights into the reasons for the slow diffusion of HRV technologies in the German building stock. It builds on the results of a recently completed research project whose central aim was to identify actor-specific and structural barriers for the diffusion of efficient ventilation systems in apartment buildings and to examine how these barriers can be addressed. The analysis is based on 40 semi-structured expert interviews with energy consultants, HVAC craftsmen, and housing companies, as well as guided in-depth interviews with private owners of apartment buildings or apartments that were evaluated by means of qualitative content analysis. Based on the collected data, seven barrier categories were identified, each containing a range of single barriers for the diffusion of efficient ventilation systems within the residential building stock. Results of the analysis were quantitatively validated by means of online surveys and a household survey among 1,008 households. The paper points out interdependencies within the chain of effects leading up to the investment decision of building owners. Furthermore, based on good practice examples identified within the data collection process, it proposes different measures to address these barriers