Conference Agenda

IAQ is an essential factor influencing health and comfort since occupants spend most of their time inside residential buildings. Indoor pollutants such as particulate matters, VOCs, Radon, high CO2 level, impact on the respiratory system heath and general well-being of occupants. Research on gaining a scientific understanding of its impact has gained momentum recently especially during Covid. However, the necessity for further study in said field remains in the UK context.

This research seeks to contribute to the database by monitoring temperature, CO2, particulate matter, relative humidity, Radon and VOCs of several houses in Nottinghamshire over a heating season in 2024. It aims to gain an improved understanding of the IAQ of typical houses in the UK and their impacting factors such as building airtightness, ventilation strategy and operational behaviour. It is anticipated that the conclusions will be useful in envisioning changes to building fabric, ventilation strategy and use of indoor spaces for increased occupant well-being and comfort.

Low-cost sensors are becoming ubiquitous for research involving indoor environmental quality (IEQ) monitoring, while Building Automation System (BAS)-grade sensors have been widely used for controlling HVAC systems. However, limited research has examined the usability and accuracy of BAS-grade sensors in place of traditional IEQ monitoring for research. This study investigates indoor air quality (IAQ) and thermal conditions in three large, mechanically ventilated university lecture halls. Low-cost sensors were placed at the front, middle and back of each hall to monitor carbon dioxide (CO2), temperature and relative humidity (RH), while the BAS provided data from return air (RA) ducts of the Air Handling Units (AHUs), collected at one-minute intervals. The coldest and warmest weeks of the monitoring period were identified using a rolling 7-day average of outdoor weather data. Time-series graphs and box plots with Wilcoxon rank-sum test were used to visualize trends and variations across these three weeks and spatial zones. Comparability between low-cost standalone sensors and BAS-grade sensors was assessed with scatter plots and Spearman rank correlation. HVAC system performance under varying occupancies and the reliability of sensors across seasons were analyzed. Findings indicate that BAS sensors can capture overall CO2 trends but may underestimate peak CO2 concentrations, likely due to the sensor placement in the return ducts and limited measurement range of the BAS sensors. Temperature discrepancies of up to 10°C between BAS and stand-alone sensors were detected, raising concerns about sensor signaling and calibration. A major issue was misconfiguration of SA and RA RH sensor data in BAS reports. These findings highlight the importance of validating BAS sensor location, calibration and configuration before relying on them for IEQ assessments. This study provides insights into whether BAS data can replace stand-alone sensors for pre-retrofit monitoring and emphasizes the need for careful sensor validation and cross-referencing with independent measurements.