Assessing thermal performance: An experimental study on U-value variability in building fabric elements

Abstract

In order to achieve energy savings in existing buildings, there is an increasing need for energy audits and performance checks. In this regard, estimating a building's U-value is crucial, and there are a variety of methods available for achieving this. Heat flow meters can be used to measure U-value in situ. This research reports on an experimental campaign that evaluated the insulation and performance of the fabric elements of a building located in Dublin, Ireland. The experimental study conducted on the ''Block F'' building provided insights into the building's thermal performance by measuring the U-value of various windows and walls across different locations and floors. The average heat loss coefficient for windows was approximately 1.74 W/(m²K) before data cleaning and 1.99 W/(m²K) after cleaning, while walls had an average of 0.90 W/(m²K) before cleaning and 1.07 W/(m²K) after cleaning. The findings revealed that similar types of windows and wall components exhibited significantly different U-values. The study identified several challenges contributing to the variability in U-value readings within the same building.

Keywords

• U-value
• Energy audit
• Thermal performance
• Building efficiency
• Insulation