Advocates of passive house design promise a lot of benefits, but the past few weeks of cold weather and combined with power failures have tested the mettle of high performance buildings of all kinds. JLC (the Journal of Light Construction) has a look at a few of them and finds that with or without electricity, during the worst of the Polar Vortex, the people living in these houses were snug as a bug in a rug.
In Chris Pike's Passive House in Vermont, they don't use the heat pump at all, just the occasional fire in the wood stove.
"Today," said Pike, "it's sunny and it's 10°F outside. It's 72°F in the house right now at one in the afternoon, and the wood stove was out by 9 o'clock this morning. On days like today where it's bright and sunny, it's almost overkill to have run the wood stove in the morning."
The article also looks at a co-housing project in Maine where the power went out for five days, but the temperature never dropped below the mid-fifties.
JLC points to a post by Cramer Silkworth of Baukraft, who shares the data on a Passive House renovation in Brooklyn that is heated by a little mini split heat pump that wasn't even turned on through most of the cold snap. He writes:
[Above] is the temperature and humidity data from a recently completed passive house... It should be noted that the temperature was measured in the living room where the family spends a lot of time. But still... I'm amazed.
Perhaps they should be called Resilient Houses, not Passive Houses
Two years ago, Alex Wilson of BuildingGreen made the case for resilient design, noting:
It turns out that many of the strategies needed to achieve resilience--such as really well-insulated homes that will keep their occupants safe if the power goes out or interruptions in heating fuel occur--are exactly the same strategies we have been promoting for years in the green building movement.
With respect to insulation, he wrote:
In achieving resilience, I believe that our single most important priority is to ensure that our dwellings will maintain livable conditions in the event of extended power outages or interruptions in heating fuel. ...The most important strategy for ensuring that those livable conditions will be maintained is by creating highly insulated building envelopes.
At the time of this writing, Hundreds of thousands of people are without power right now in Pennsylvania. The whole Northeast has been going through cold like we haven't felt for years. If anyone ever needed a lesson in why we should stop building glass towers and why we should be building to far higher standards of insulation, this has been it. The people who are living in Passive Houses are sitting pretty while everyone might freeze in the dark.