Well, I really stirred things up with my last article on insulation and global warming. My intention was to explain why Alex Wilson’s results could be doing a disservice to the green building community. In the end, I was rightly accused of have done a disservice myself.
So, here goes with Part Three of my take on the global warming impact of insulation. Let’s see if I can get closer to the truth this time.
A public apology to Alex Wilson
First, I need to apologize to Alex Wilson. I apologized privately at the time of my last article. Now I do so publicly. I wrote things that went too far, saying his results were bogus and he was engaging in pseudoscience. I regret those comments and have removed them from that article.
As I’ve said before, Alex Wilson has done great work in his career. He’s taken green building further than just about any other person in the field. His Environmental Building News has set the standard for green building news and analysis for decades. He also has a background in science and takes science seriously.
Wilson’s insulation and global warming study
Since that last article, I’ve done more reading of Wilson’s 2010 article, Avoiding the Global Warming Impact of Insulation, and related works, as well as discussing it with others. Briefly, what he did was to calculate the amount of time a highly-insulated wall assembly would have to be in service to “pay back” in reduced carbon emissions the amount of global warming created by the insulation itself. That insulation impact, he stated, comes from two things: the embodied global warming potential (GWP) and the GWP of the blowing agents used in foam insulation. His conclusion was that extruded polystyrene (XPS) and…