Window Energy Efficiency: Thermal Transmittance

By | 2017-11-07T15:14:36+00:00 March 30th, 2016|Mechanical Engineering, Thermal Management|

Figure 1: Windows catching sunlight By Magda S [ Content License] In our last blog post, I wrote about the thermal resistance (R-value) and transmittance (U-factor) of insulation and windows.  The R-value represents how well a material prevents heat transfer through its thickness, and U-factor is its inverse, representing how much heat a material will conduct through.  These values are fairly simple to calculate for most building materials materials like the bricks and panels in Figure 1, as they primarily experience only conductive heat transfer.  Windows are a more challenging proposition, however, since the heat transfer through them [...]

Energy Efficiency in Building Materials, Insulation and Windows

By | 2017-11-07T15:05:13+00:00 March 24th, 2016|Mechanical Engineering, Thermal Management|

Figure 1: FLIR image of two houses showing energy loss. Colors towards red on the scale indicate warmer surfaces and more energy loss. The basic principle behind thermal insulation is simple to understand.  The harder it is for heat to travel through a material, the better insulator that material will make.  In this blog, I’m going to take a look at how that effectiveness is quantified, after a brief review of the three methods of heat transfer.  The building and construction industry use a ratio called the R-factor to indicate how well a building material can insulate a space.  [...]