Building envelop energy efficient retrofitting options for domestic buildings in the UK

Abstract

Retrofitting options to improve the thermal efficiency of external walls of domestic buildings are presented for three types of properties built in the UK. Case study one is a semi-detached, two-storey building, built ca. 60 years ago, with a brick outer skin, a hollow cavity and a block work inner skin; case study two is a mid-terraced, two-storey building built ca. 120 years ago, with a solid stone wall and render; and case study three is a semi-detached, two-storey building, built ca. 60 years ago, with a reinforced pre-cast concrete outer skin, a cavity and a block work inner skin. The most appropriate retrofitting options considered were: (i) installing cavity insulation; (ii) attaching internal wall insulation; and (iii) mounting external wall insulation, respectively. In each case study the retrofitting options demonstrate notable improvements can be made in the thermal performance of the buildings. Moreover, all retrofit approaches provide sizeable energy cost savings per annum, with case study three providing the largest savings and case study one proffering the shortest payback period. Cavity wall insulation emerged as most beneficial retrofit option, in regards to capital cost, quickest payback period and minimal disruption in the installation process. However, homeowner motivation to instigate retrofit options is acknowledged as a significant barrier and, when married with the associated disruption and inconvenience of implementing home improvements, it is viewed