Thermal performance of the window frame material in residential Maltese buildings

Abstract

In buildings striving for energy efficiency, it is important to consider each element and component that makes up the building envelope. One such element is the window; this plays a significant role in the thermal performance of residential buildings, among others. One component of the window that is seldom given importance is the choice of the frame material. Even though the window frame constitutes of a small fraction of the area of the bare window opening, it is still a significant area regarding possible heat transmission. This is particularly important for residential buildings, given their small size of openings. The primary objective of this dissertation was to investigate three typically sized sample window frames that exist in the Maltese market. There are currently three window frame materials that are considered as rnn of the mill. Materials chosen were therefore: timber, Polyvinylchloride (PVC) and aluminium. The three window samples were tested both through an on-site experimental analysis as well as through computer simulation software. In the fieldwork surface frame temperatures were monitored to calculate the thermal transmission through such window frame profiles. Separately, THERM software was used for the simulations. Moreover, empirical theoretical calculations were used to establish the U-value of each window. The analysis provided a pattern that was present throughout all the logged temperature data during the fieldwork and calculated U-value from both the experimental analysis and the software simulations. Such pattern was that the aluminium frame window was the worst thermal performer material. While the timber window performed second best, with the PVC window performing the best regarding both the logged temperature readings and the calculated U-value.