Effects of retrofit insulation on space heating consumption : a case study of a high-rise social housing building in Newcastle upon Tyne, UK

Abstract

Different policy instruments have been applied to raise the energy efficiency in low-income and vulnerable households. However, previous studies suggested that, due to temperature take-back, occupants take part of the energy consumption saving after energy efficiency upgrades as increased internal air temperatures. The aim of this study was to investigate the effects of retrofit insulation on space heating consumption to deepen the understanding of the temperature take-back. This study used an integrated approach to take into account the complex interactions of physical and occupants’ behavioural factors; quasi-experimental and qualitative approaches. A quasi-experimental approach involved detailed internal air temperature monitoring of a sample in a high-rise building pre- and post-retrofit, and monthly space heating consumption for over a year of each flat dwelling at the retrofitted building, which was compared to a control building. A qualitative approach involved the collection of occupant responses pre- and post-retrofit. The main findings were: 1. Following retrofit the mean internal air temperature of the high-rise retrofitted building increased +0.46˚C (22.07˚C to 22.53˚C at 5˚C external temperature) and could attain a 27% space heating saving (34% relative to a control group); 2. The effect known as saturation was taking place due to internal temperatures’ reaching a maximum level of thermal comfort (~22.5°C); 3. No evidence was found that would suggest that occupants were using their homes more intensively or had changed the use of space. These empirical findings suggested that assumptions normally made about low-income dwellings ‘taking back’ energy savings as increased temperatures did not accurately reflect the reality of the energy efficiency upgrades in the case study – particularly, energy efficiency retrofit upgrades that achieve saturation. The study suggested that energy efficiency measures targeting low-income dwellings designed to achieve saturation might prevent temperature take-back, and achieve both thermal comfort and low-energy use. However, a possible risk of overheating was also suggested in the non-heating season.