Everybody loves passive solar design. Back in the 1970s, “passive solar” was the essential first step for cold-climate builders. It was considered an approach with obvious advantages over complicated “active solar” schemes that required pumps, fans, and electronic controls.
While the definition of a “passive solar house” was well established by the 1980s, Wolfgang Feist muddied the waters in the 1990s when he decided to call his new superinsulation guidelines “the Passivhaus standard.” Ever since that fateful day, journalists and owner/builders have confused passive solar design principles with Feist’s superinsulation standard from Germany.
Rather than focusing on the confusion between passive solar design principles and the Passivhaus standard, however, I’d like to travel back in time to the 1970s, the heyday of the passive solar movement, to identify the original principles espoused by passive solar designers. Once these principles are identified, we’ll examine how many of them have stood the test of time.
Here are the five bedrock principles of passive solar design for a cold climate:
Solar vs. superinsulation
In October 2009, the Passive House Institute U.S. invited me to give a presentation at the Fourth Annual North American Passive House Conference in Urbana, Illinois. In that presentation, “The History of Superinsulation in North America,” I discussed the debate between “solar house” advocates and superinsulation advocates during the late 1970s and early 1980s. After Joe Lstiburek and John Straube saw my presentation online, I was invited to present it again at the 14th Annual Westford Symposium on Building Science (August 3, 2010).
Some of the information from that presentation was incorporated into a 2010 GBA article, Solar Versus Superinsulation: A 30-Year-Old Debate.
Here’s a quick summary of the relevant history: during the late 1970s…