The UK Government is planning large-scale deployment of domestic heat pumps, yet there is limited data on the indoor air quality (IAQ) implications of moving to low carbon heating. This paper undertakes empirical measurement of IAQ before and after smart heat pump retrofit in five naturally-ventilated social housing flats in Oxford. Plug-in Airthinx sensors monitored IAQ parameters including CO₂, Particulate Matters (PM2.5, PM10), formaldehyde (CH₂O) and Volatile Organic Compounds (VOCs: ethanol and Isobutylene), temperature and relative humidity (RH) in the living rooms of all flats during the heating season, for one week before and one week after heat pump installation. While indoor temperatures were more stable post-retrofit, indoor pollutants including CO₂ levels fell below 900 ppm over 90% of the monitored hours in majority of flats, mainly due to change in residents’ window opening behaviour driven by constant heating provided by the heat pump. Across four flats, post-retrofit, formaldehyde levels were found to be less than WHO recommendation, while mean daily levels of PMs continued to be higher than recommended levels in three flats due to occupant smoking habit. The levels of ethanol and isobutylene showed reductions post-retrofit. It is vital that upgrades to heating system consider IAQ parameters beyond temperature and RH.
Gupta, RajatZahiri, Sahar
School of Architecture
Year of publication: 2022Date of RADAR deposit: 2023-09-15