residential ventilation

With rising insulation standards and air tightness in buildings, the use of mechanical ventilation becomes more relevant. In this context, energy recovery offers a significant contribution to the decarbonisation of building operations. Heat recovery systems are widely spread in residential ventilation. Moreover, enthalpy exchangers recovering sensible and latent heat have an increasing share of use in residential ventilation, especially in cold climates, as they not only reduce the energy demand but also increase the indoor air humidity in winter seasons.

Metal Oxide Semiconductor (MOS) sensors measuring Volatile Organic Compounds (VOC) seem to be an obvious step towards broadly available Demand Controlled Ventilation (DCV). The previous research shows that MOS VOC sensors can detect high pollution events such as cleaning, painting, or high occupation density. These abilities seem to make MOS VOC sensors suitable to complement ventilation control systems, especially concerning residential ventilation.

The Performance 2 project (2020-2024) is a French national research project that aims to evaluate the durability of Humidity-based Demand Controlled Ventilation (DCV) systems installed in two multi-family social housing buildings (Paris and Villeurbanne) over than 10 years ago. This evaluation includes the analysis of continuous measurements performed on the ventilation system (sensors located close to the air terminal devices) and two additional Indoor Air Quality (IAQ) campaigns including two other monitors placed in the “dry” rooms conducted in 13 dwellings.

We need to improve the indoor air quality for the health of the building users, and we need to optimize and reduce energy consumption for heating, cooling, and ventilation for the sake of the global climate. In both cases the interplay between buildings, HVAC (heating, cooling, and ventilations) technologies and the users are central. Research show that technical optimization without considering the interaction and behaviour of the users may end in sub-optimal technical solutions, neither resulting in reduced energy consumption nor improved indoor air quality.

The common demand control approach for MVHR systems using one CO2 sensor within the ventilation unit is assessed based on a typical residential apartment situation using CONTAM models. The simulation results confirm that air flow and therefore fan electricity and ventilation losses can be reduced compared to constant flow control, in particular for higher nominal air exchange rates. However, under certain boundary conditions, e.g. unevenly occupied dwellings indoor air quality in certain rooms may suffer with this DCV strategy.  

Ambitious goals regarding CO2 neutrality put the energy renovations of apartment buildings in the top places on the energy efficiency & sustainability agenda in Denmark. Improved airtightness and maximum primary energy requirements imply utilization of ventilation with heat recovery. The control of ventilation installed during renovations often considers a whole dwelling as one climate zone, which neglects differences among individual rooms. Increased insulation and tightness leads to higher sensitivity to solar and occupancy gains, moisture loads and pollutants.

Humidity-based DCV systems have been widely used in France for 35 years and are considered as a reference system, including for low-energy residential buildings. The on-going Performance 2 project delivers the new results of a thirteen-year monitoring in twenty-two social housing apartments. The involved consortium is composed of Cerema, Univ. Savoie Mont Blanc and two industrials partners: Aereco and Anjos. 

IEA-EBC Annex 86 “Energy Efficient IAQ Management in residential buildings” aims to propose an integrated rating method for the performance assessment and optimization of energy efficient strategies of managing the indoor air quality (IAQ) in new and existing residential buildings. Our goal is to work in an international collaboration so that the different approaches to design and operation of ventilation in different countries are accounted for.

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.