Volume 39, Issue 3 (May 2011)
Interior Metal Components and the Thermal Performance of Window Frames
In an effort to reduce the likelihood of condensation at metal window frames and glazing, methods to improve the thermal performance are now readily available, such as thermal breaks and warm edge technology. Despite technological improvements, metal window frames may still exhibit interior surface condensation if the installation details or interior environmental conditions create circumstances that compromise or breach thermal breaks. The U-factor, condensation resistance (CR) factor, and CR are often utilized to compare the thermal performance of fenestration products. However, these performance parameters do not necessarily result in adequate CR of windows in service. As a result, remedial measures are commonly required to alter or modify the window details after installation. Computer software programs can be used to evaluate the thermal performance of window components and various installation details under steady-state conditions are available, as well as approaches to correcting condensation/frost formation issues. Computer simulated repair approaches indicated that the application of additional metal components on the interior may effectively raise the interior surface temperatures of the window frame. Our study will evaluate the feasibility of the “metal fin” in practice, the impact of installation techniques, as well as relate the findings of simulations to mockups. In summary, this paper explores the affect of in situ repair efforts to raise the interior surface temperatures of metal window frames and indirectly on the likelihood of surface condensation on the frame.