Four weeks into physical distancing for the COVID-19 pandemic, I am reminded of the last major crisis that suddenly altered my daily life. I was a teenager when the January 1998 ice storm ravaged the Southeast of Canada, leaving us without electricity for 29 days.
Like many homes in rural Quebec, our house had electric baseboard heaters and our water came from a well. Losing electricity meant losing heat and running water. Luckily, we had a wood stove for back up heat, so we kept a fire going and slept near the hearth. Water for washing was hauled from the nearby river and drinking water was bought and used sparingly. All of the energy required to keep us warm and clean, which had previously been delivered invisibly via thermostats and the well pump, was suddenly made tangible when we had to fetch each log and each bucket of water ourselves. Crises shine a light on how we meet our most basic needs, and how much shelter our homes provide.
Mitigation and Adaptation
When we think of the relationship between buildings and climate change, we tend to focus on mitigating the effects of climate change by reducing greenhouse gas emissions. Buildings also have a role to play in how we adapt to the realities of an altered climate with more frequent extreme weather events.
The Toronto Zero Emissions Building Framework (TZEBF) was the first policy that drew my attention to building resilience as a public health issue. The City recognized that if a winter storm causes a prolonged power outage, there is a direct correlation between building energy efficiency and whether people can safely shelter in place in their homes. If interior temperatures drop too low due to poor insulation and air leaks, then large numbers of people need to be evacuated, potentially exceeding the capacity of the city’s emergency response system. The importance of climate mitigation and adaptation is evident in the TZEBF’s three intersecting goals: lower GHG emissions, higher energy efficiency and improved building resilience.
Sheltering in place
In order to evaluate building resilience, the TZEBF includes simulations of interior temperatures in low-rise and high-rise multi-unit residential buildings after 72-hour and 2-week power outages. The TZEBF defines four tiers of increasing energy efficiency. Tier 4, the most ambitious tier of performance, has the same 15kWh/m2a Thermal Energy Demand Intensity (TEDI) as the Passive House Standard. After two weeks without a functioning heating system in the middle of winter, the Tier 4 high-rise has an interior temperature of 18.3°C. By comparison, a high-rise designed to the minimum requirements of the current building code would be down to 9.9°C after 72 hours and 0.9°C after two weeks.
The low-rise building did not perform quite as well, which is to be expected because smaller buildings have a lower surface area to volume ratio and lower internal heat gains since they are less densely populated, but it would be warm enough to allow people to shelter in place for a 3-day outage, and there would be a lower risk of damage due to frozen pipes, even after two weeks without power. Detailed information about the simulations, along with information about the cost implications of improved energy efficiency can be found here.
Conclusion
Using passive design strategies to drastically reduce the energy needed to heat buildings means that people can shelter in place safely in the event of a power outage, and that a modestly-sized back-up power system can keep the building operational since it doesn’t need to compensate for excessive heat loss.
Extreme events like the ’98 ice storm or the COVID-19 pandemic alter our daily habits and make us more aware of our consumption, whether it is keeping a fire going to stay warm during a power outage or putting food on the table while minimizing our interactions with the outside world. A time of crisis is an opportunity to refocus on what is truly essential. If we collectively reduce our consumption then resources can be shared more equitably and the whole community is more resilient.
Comments