Curtain Wall Efficiency

Kyle Olugbode
December 14, 2014

Submitted as coursework for PH240, Stanford University, Fall 2014


Fig. 1: Google Campus. (Source: Wikimedia Commons)

The Silicon Valley is home to many the world's most successful tech headquarters. Google, Apple, Facebook, and Yahoo are just a few of the most formidable names in the tech industry and they each have their campuses located in the area. Upon examining each of these companies' headquarters, it is interesting to see how much glass they incorporate on their exteriors. I was interested into looking into their use of curtain walls and some features used with curtain walls today that help keep buildings energy efficient.

Curtain Walls

Curtain walls are a very aesthetically pleasing feature for buildings. They allow buildings to take advantage of natural daylighting. They make buildings appear "light" without having the typical enclosures of concrete or heavy walls. And they also give the building a sense of transparency for visitors viewing the building from afar. With all of the benefits extensive glass use and curtain walls can provide aesthetically, they can negatively affect a building's energy efficiently if not installed carefully.

Fig. 2: Insulation System. [2]

Curtain walls essentially serve as floor to ceiling windows, so while allowing daylight in heat can also enter and leave the building quite freely due to its "potential for large heat gains and losses." [1] In the winter, the large amount of glass can potentially hurt you heating bill by letting heat out; and in the summer, energy costs can rise due to the heat of the daylight entering causing occupants to want air conditioning.

Possible Solutions

Asking for wholesale changes to the average American diet can be too ambitious, but I do think it is important to be aware that a large amount of energy goes into the production of the food we eat. Some suggestions to think about the next time you're purchasing meat include whether or not the livestock was grass-fed. Grass-fed livestock is less energy intensive since it eliminates the corn feeding the process. We can also look to support local economies more in determining food choices. [2] When we eat locally grown food or meat less transportation is required which decreases energy cost. Maybe try taking one day out of the week without meat.


Features such as glazing and insulation can help limit the ease in which heat flows into and out of a building. "Low-E" glass, low emissivity, is a glazing that takes advantage of the Sun's visible light while limiting the amount of heat that typically travels with it, especially in the summer. Creating the glazing is achieved by coating the glass with a variety of metals and chemicals including silver and silicon. This coating gives the glass the ability to deflect the infrared quality of light which carries heat. [3] Another way you limit heat transfer in curtain walls is with insulation. Systems can be installed between the connections of each glass panel (Fig.2). Focusing on the connections can eliminate any possibility for air leakage as well. [2]

© Kyle Olugbode. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.


[1] A. I. Rubin, B. L. Collins, and R. L. Tibbott, Window Blinds as a Potential Energy Saver: A Case Study (U.S. National Bureau of Standards, 1978).

[2] E. Hubbard, "System for Improving Heat Insulating Characteristics of Existing Curtain Walls and the Like," US Patent 4207717, 17 Jun 80.

[3] K. W. Hartig and P. J. Lingle, "For Architectural Use, High Visible Transmittance and Infrared Reflection, Sputter Coated," US Patent 5344718," 6 Sep 94.