QUB/e: A novel transient experimental method for in situ measurements of the thermal performance of building fabrics

Abstract

This paper presents a novel transient experimental method developed in order to perform in situ measurements of the thermal performance of building fabrics: the QUB/e method. In one night, a QUB/e test yields the whole house heat loss coefficient (HLC) and the local in situ U-values. A comprehensive set of in situ measurements were carried out in a circa 1900 solid wall end-terrace house located in an environmental chamber to evaluate the thermal performance of the building fabric and to validate the QUB/e method. The accuracy of the QUB/e method was assessed against steady-state measurements before and after a deep retrofit, both the HLC and U-values were used in the comparison. The measurement of the HLC using the QUB/e method for heating durations down to one hour yielded accurate results (i.e. the relative differences from the value estimated with the steady-state method were smaller than 10%) provided the a-criterion lay within the recommended range (i.e. between approximately 0.4 and 0.7). The U-values measured in situ with the QUB/e method were in good agreement with the steady-state (ISO 9869-1) values (i.e. the relative differences were within the uncertainty bound of the measurement methods). The QUB/e method was thus deemed validated by comparison with reference U-values measured in accordance with ISO 9869-1.