Innovation Profile: How the Heat Dome Reaffirmed Mike Fowler’s Passive House Path

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Profile in Innovation: This article is one in a series that will highlight new and innovative technologies and profile people making a mark in support of the passive house community’s efforts to decarbonize buildings.

By Lia Grainger

When architect Mike Fowler sees an opportunity, he raises his hand. He says yes. Particularly if it’s an opportunity to make something — a building, a project, a guideline — more sustainable.  

“It’s funny how one little step leads you in a direction, and then another one, and one day you look back and there it is: the path that got you there,” says Fowler of his 30-year career. 

Today, he works in the Seattle offices of architecture firm Mithun, where he’s a senior associate and sustainability integration leader. Of course, he’s also got some extracurricular activities. He represents architects on the Washington State energy code advisory group. He created a roadmap to reduce energy use in Washington State by 70 percent by the year 2030. He was the board president of Passive House North West for three years. Fowler knows how to keep himself busy, and the past whirlwind year has been no exception. He’s been hopping from global conference to conference to talk about the deadly weather phenomenon known as a heat dome, and how Passive House measures have the potential to save lives. 

Born in Washington, DC, Fowler started his career in the late 1990s at an architecture firm in Albany, New York. 

“I’ve always been excited by sustainability,” says Fowler. So much so that he decided to start an in-office “green team.” When an early project needed LEED certification, Mike’s hand shot up, and he and the green team began work on what would become one of the earliest LEED-certified buildings. 

In 2000, Fowler moved to Seattle to be closer to family, and began looking for a job. Mithun was at the top of his list. The firm had just won the American Institute of the Environment Award for the REI flagship store in Seattle, a sprawling complex with interactive test areas for climbing, camping, skiing and paddling. He landed the job, but didn’t rest on his laurels for long. When a group of local architects decided to get together to lobby the state of Washington to adopt LEED for anything with state funding, who do you think heeded the call?  

“Yeah, I got involved,” says Fowler. Today, any state-funded builds must be LEED Silver certified.  

In 2005, the lead architect advising the state on its energy code decided to step down.  

“Well, being young and eager and not knowing anything, I was the only one who volunteered,” says Fowler with a laugh. Suddenly he was heading a tech advisory group, reviewing all new proposals to change the state’s energy code.  

Of course, Fowler’s career path hasn’t always been a stroll down easy street. The economic downturn of 2008 hit particularly hard, and Fowler found himself laid off. He landed a job at a local utility Puget Sound Energy, where he managed their incentive program for 4 years. It was during this time that he was introduced to Passive House – an intro that came from the ultimate authority. 

“It was fun to meet Wolfgang Feist and learn about it directly from him,” says Fowler. The co-founder of Passive House, Feist was speaking at a conference he was attending, and Fowler was transfixed. 

“These German building principles were so good. It gave me the same feeling that LEED did in the late nineties — there was so much potential,” says Fowler.  

At Puget Sound energy, he began incentivizing Passive House principles for new residential builds in the region, and he continued attending Passive House conferences around the world in his spare time. He took the training to become a certified Passive House Consultant. He joined the local North West Passive House group, and by the summer of 2018, he was the board president.  

And then, in the summer of 2021, the western heat dome hit. 

“I don’t remember anyone talking about heat waves before that, especially here in the northwest,” says Fowler.  

At the time, he was part of a research study team at the University of Oregon looking at passive measures for insulation, optimizing when to let the sun in, when to let the air through.  

“Some of it is machine learning,” says Fowler. “ Humans can be slow to respond. I might open the window when I start to feel hot, but the optimal time to have opened it was three hours ago.”  

It was while working on this project, in late June 2021, that Fowler remembers checking the weather in Oregon. The forecast: 46.7 degrees celsius.  

“I couldn’t believe what I was seeing,” says Fowler.  

A heat dome occurs when a ridge of high pressure hot air becomes trapped by the atmosphere, as if under a lid. Heat expands upward and is pushed back down towards the ground, leading to higher and higher temperatures.   

From June 25 to July 2, temperatures soared across western Canada and the United States. In Lytton, BC, temperatures hit 49.6C. The next day, the entire town burnt to the ground. By the time it was over, more than 1,400 people had died from the heat.  

In a subsequent report on the heat dome, Dr. Sarah Henderson, Scientific Director of Environmental Health Services at the British Columbia Centre for Disease Control, reported that the majority of these deaths had actually happened inside people’s homes.  

“People don’t die because it is hot outside; they die because it is hot inside,” wrote Henderson. 

For Fowler, the event was eye opening.  

“We realized that what we were already studying had the potential to keep people alive,” says Fowler.  

Experts in the field were already studying how Passive House measures could help mitigate a warming climate, but most models looked at an increased temperature of just a few degrees. Yet during the western heat dome, temperatures were 22.2 C above average. How would Passive House measures (like insulation, shading, and night-air cooling) stand up to such inflated temperatures? 

Using hourly meteorological data from the 2021 heat dome, Fowler and his colleagues modelled how such extreme temperatures might affect a series of hypothetical fifth floor, 800-square-foot-units built to either the 2018 International Energy conservation Code or the the ASHRAE 90.1 1989 code. They then examined how well a variety of Passive House measures mitigated those extreme temperatures, and found that a combination of exterior shading and fan-assisted night cooling performed the best.  

Their modelling also found that during the 72 hours of the heat dome’s most extreme temperatures, passive cooling strategies kept the interior heat index below dangerous levels, even in the older unit built to 1989 code.  

The research was published in Applied Energy in June 2022, and Fowler has been explaining the results to eager audiences at conferences around the world ever since. It’s been a busy time, but Fowler’s never been one to shy away from the action, particularly if it’s for something he believes in.  

“These extreme heat events are going to happen more and more. They already are.” says Fowler. “I’m happy to be sharing how Passive House can actually keep people safe and alive as the world gets hotter.” 

Join Mike Fowler at the Passive House Canada Conference

Extreme heat events are becoming more frequent and severe, increasing the occurrence of heat-related illness and death. Many occurrences are attributed to overheating in multi-unit dwellings, particularly in neighborhoods with abundant asphalt, few trees, and limited financial resources. Future climate projection tools estimate new, higher average temperatures by a few degrees but do not predict extreme heat events such as the 2021 Heat Dome with +20°C above average temperatures. Using exact meteorological data from Portland, Seattle, and Vancouver for that event, this session will share modelling results for how hot interior temperatures can become, the associated health risk, and how Passive House can dramatically reduce the risk during extreme heat events.

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