An Unintended Effect of Energy-Efficient Buildings: Toxic Mold

Illustration for article titled An Unintended Effect of Energy-Efficient Buildings: Toxic Mold

Energy-efficient buildings can be wonderful at keeping out drafts and keeping down heating bills. But the same air-tightness, unfortunately, is also perfect for trapping humid air where toxic mold can go to party.

The Alberta Court of Appeal in Canada has been a mold-filled ghost building since 2001, after renovations to the handsome, 87-year-old sandstone building went awry. When the renovated and newly energy-efficient building reopened, according to ClimateWire, judges and attorneys complained of fatigue, irritated lungs, and watery eyes.

Air quality samples pointed the finger at mold growing inside the walls. The cracks and leaks of the pre-renovation building had been a crude form of air-quality control—albeit not very energy efficient. The new airtight building, however, trapped moisture to breed toxic mold.


The court eventually moved to an office tower downtown, but the mold permanently contaminated its archives. Record requests are a real pain. "Mold still lingers in paper court documents," Umair Irfan writes in ClimateWire; incredibly, this requires "someone with a respirator to retrieve and scan contaminated files to send to officials as requested."

On one hand, building energy-efficient structures seems to better shield us from the elements, creating a well-insulated barrier between us and the environment. But the unintended consequences of energy efficiency show just how mindful we need to be of the natural world. Mold grows in airtight walls. Ice sheets form and then crash down from well-insulated skyscrapers.

As an increasing body of research catalogues the microbes living in our buildings, we also have to consider the invisible microbiology of the built environment. The microbiome of the human body and that of the places we live are inextricably linked. We certainly want to discourage toxic mold for health reasons, but what about encouraging the good microbes—even on a city-wide scale?


Probiotics, like those found in yogurt, are the good bacteria we want, and prebiotics are the fuel that promote growth of those bacteria. We could think about "prebiotic design"—ranging from coatings for wood floors to fine-grained temperature controls—that promote a healthy microbial environment inside our bodies and out. [ClimateWire via microBEnet]


Top image: Matti Mattila/Flickr

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Al Roderick

The contractors who specialize in making and renovating for efficiency already learned this after some early failures, every high-performance project house and building I visit has a robust air-quality and ventilation scheme in place for it even if it doesn't have a traditional heating and AC system. A tight building's HVAC needs to provide fresh air more often than it provides hot or cold air, and right now only a small portion of HVAC systems are set up to do that automatically. Old government buildings tend to use radiant heat, so there may not even be much of an active vent system in place.

A lot of organizations get into trouble when well-meaning people are fiscally responsible and think that paying for a relatively cheap insulation upgrade will mean reaching an energy target without replacing a very expensive commercial HVAC system. In our day-to-day lives we don't think about this stuff until we see the results.