Magnitude and extent of building fabric thermal performance gap in UK low energy housing

Gupta, Rajat, Kotopouleas, Alkis (2018) Magnitude and extent of building fabric thermal performance gap in UK low energy housing. Aplied Energy, 222 . pp. 673-686. ISSN 0306-2619. (doi:10.1016/j.apenergy.2018.03.096)

Abstract

This paper presents new evidence from a nationwide cross-project meta-study investigating the magnitude and extent of the di?erence between designed and measured thermal performance of the building fabric of 188 low energy dwellings in the UK. The dataset was drawn from the UK Government’s national Building Performance Evaluation programme, and comprises 50 Passivhaus (PH) and 138 non-Passivhaus (NPH) dwellings, covering di?erent built forms and construction systems. The di?erence between designed and measured values of air permeability (AP), external wall/roof thermal transmittance (U-value) and whole house heat loss were statis- tically analysed, along with a review of thermal imaging data to explain any discrepancies. The results showed that fabric thermal performance gap was widespread especially in terms of AP, although the magnitude of underperformance was much less in PH dwellings. While measured AP had good correlation with measured space heating energy for PH dwellings, there was no relationship between the two for NPH dwellings. The regression analysis indicated that for every 1 m3/h/m2 reduction in designed air permeability, the gap increased by 0.8 m3/h/m2@50 Pa. Monte Carlo analysis showed that likelihood of AP gap was 78% in NPH dwellings designed to 5 m3/h/m2@50 Pa or lower. The study provides useful evidence for improving the fabric thermal performance of new housing through in-situ testing.

Item Type:	Article
DOI/Identification number:	10.1016/j.apenergy.2018.03.096
Uncontrolled keywords:	Building fabric Low energy dwellings Passivhaus Airtightness Heat loss Thermal transmittance Co-heating test
Subjects:	N Fine Arts > NA Architecture T Technology > TH Building construction
Divisions:	Faculties > Humanities > Architecture
Depositing User:	Alkis Kotopouleas
Date Deposited:	07 Sep 2018 14:21 UTC
Last Modified:	29 May 2019 21:06 UTC
Resource URI:	https://kar.kent.ac.uk/id/eprint/68987 (The current URI for this page, for reference purposes)