English

Airtight, highly insulated, and passively cooled buildings in the EU are designed under typical outdoor and indoor thermal conditions. With increasing risk and uncertainty with regards to climate change and associated heatwaves(HW), the design thermal performance of these buildings is not guaranteed. It is crucial to focus on improving thermal resilience to overheating and futureproof these buildings. “Thermal resilience to overheating” is the characteristic that describes the extent to which buildings and their cooling strategies can maintain habitable conditions during or post shocks.

This article provides a summary of a comprehensive examination of the current ISO 9972 standard, focusing on the enhancements needed to improve its reliability and validity for airtightness tests in buildings. A working group composed of international experts has identified a list of issues warranting a potential revision of the standard. New recommendations are proposed based on research and consultation, including detailed considerations of previous guidelines and existing scientific literature.

The content presented comes from the paper under review “Quantitative correlation between buildings air permeability indicators: statistical analyses of about 500,000 measurements” (Moujalled, 2023a).

Improving the knowledge on uncertainty for fan pressurization measurement is of first importance. It allows to assess the reliability of the measurement, which is essential when comparing the results with benchmarks or standards, but it also gives a better understanding, and thus a chance of improving, the measurement procedure. In this context, recent studies on alternative regression techniques highlights the importance of identifying and quantifying the sources of uncertainty.

Gas-phase air cleaners can be used to either reduce occupant dissatisfaction for the same outdoor air flow rate or to reduce the outdoor air flow rate for the same resulting occupant satisfaction based on its clean air delivery rate (CADR). The latter lowers the required ventilation rate for the same indoor air quality and can thus lead to a reduction in energy use for preheating/cooling and from transporting the outside air. However, there is no current method or metric for determining the energy benefit of installing a portable air cleaner.

This manuscript discusses the energy-saving benefits of gas-phase air cleaning in Nordic buildings. Ventilation systems are crucial in creating a healthy and comfortable indoor environment. These systems account for around 30% of building heat losses in cold climate regions. Indoor emissions from materials, occupants, and outdoor pollutants are key to ensuring acceptable indoor air quality levels. Therefore, this study focuses on using gas-phase air cleaning technologies in low-energy centralized air handling units.

Indoor air pollution is a significant concern due to its adverse effects on human health and productivity. With people spending most of their time indoors, exposure to indoor air contaminants can lead to various health issues, including respiratory problems, cardiovascular diseases, and even an increased risk of lung cancer and premature mortality. Additionally, poor indoor air quality can result in short-term symptoms like headaches, eye and throat irritation, fatigue, and asthma, impacting workplace productivity and absenteeism.

International Energy Agency (IEA) Annex 78 was launched in 2018.

Due to global warming, severe problems of buildings overheating during summer in temperate and hot climates arise. Thus, there is an increasing use of air conditioning. However, alternative passive and soft cooling systems exist to address comfort and energy savings issues, such as natural ventilation or ceiling fans, that consume less energy. Although they are well-known today, their use remains under-enhanced.

Over time with thermal and energy regulations, buildings are increasingly insulated and airtight to control better the heat exchanges between the indoor and outdoor environments. The primary function of the mechanical ventilation system is to ensure healthy air by diluting odours and humidity with fresh air. However, in many situations, windows opening can be much more effective in terms of thermal comfort, air quality, or release heat loads due to a higher air change rate than the mechanical ventilation system itself.