To Cool or Not To Cool?
“In my experience, people don’t actually want air conditioners in their homes; what they want are homes that don’t overheat in the summer.”
"Do we really need air conditioning in Saskatoon, where we only have hot weather for about 2 weeks of the year?" I ask this question at the outset of every project that we do and I tend to drive both my architects and project engineers crazy with it.
The answer that continually comes back to me is "well, it depends on the house." Indeed, our need to use air conditioning depends heavily on how our homes are designed in the first place; factors like building orientation, southern exposure, the amount of glass, insulation levels, roof colour and even the type of lighting we use factor into the need for actively cooling spaces by using air conditioners.
At Shift Development, we've always put the emphasis on conservation first and technology second. Credit goes to my late mentor and friend Rob Dumont, who has been called the Jedi Master Yoda of energy efficiency. Dumont's expertise has influenced Shift's approach. That's why the homes we build always have triple glazed windows, higher levels of insulation and heat recovery ventilators. We've stopped short of installing solar panels or more complicated (and expensive) technological solutions in order to keep our prices down--but those options are always available for homeowners to pursue on their own, after they move in.
We know that these strategies have made our Mosaic townhouses very energy efficient. But for Element Urban Village: Phase 2 we wanted to quantify the difference such a design strategy made on efficiency.
In order to get some hard numbers, we handed off our design of Phase 2 to an engineer who specializes in energy modelling and PassivHaus design. The cooling requirement for PassivHaus certification--which is one of the most stringent energy related certification standards out there--is that a PassivHaus cannot risk overheating for more than 10% of the year. PassivHause Designers typically aim for 5%, to ensure they meet the requirement, with some slack.
The analysis that came back on our units in Phase 2 of Element Urban Village was surprising, coming in at a 2% risk of overheating, well below the PassivHaus requirement.
Goodbye air conditioning...
With the analysis results in-hand, we decided not to include air conditioners in each Phase 2 unit. These homes will perform so well that air conditioners are simply not necessary. Further, our consultant recommended that if we simply upgraded our air exchanger to a higher performance unit, we could also capture free night time cooling from our cool summer nights and reduce the risk of overheating even further.
On the heating front, the energy modelling results were also encouraging (follow me down the rabbit hole a bit here...). We're planning for a centralized boiler as the source of heating at Phase 2, with individual air handlers in each suite. Once we incorporate a few other recommendations, particularly towards improving insulation levels, the heating requirements of Phase 2 should be approximately 1/3 of the average Canadian residence (50 kWh/sq m vs 150 kWh/sq m). This is a solid demonstration of what can be achieved through smart and integrated design thinking. Home run.
In my experience, people don't actually want air conditioners in their homes; what they want are homes that don't overheat in the summer. Understandably, many people don't have the interest or experience to investigate their home's mechanical systems or learn about the building envelope that keeps them warm in winter and cool in summer--despite the fact that making improvements here is a significant step we can take towards sustainable lifestyles on the home front. That's why Shift obsesses over these details; they matter, and getting them right advances our goals for environmental sustainability. And who wants to spend money on big utility bills anyway? Grab those savings and use them to create a great night out in Riversdale!
At our annual staff retreat, Shift Development committed to an important goal: to achieve net zero energy buildings in our housing projects by 2020. Happily, Element Urban Village: Phase 2 is a strong step forward towards this goal.
That being said, we still have a lot of work to do to reach our net zero goal, and we can get their faster with help from others. Shift embraces transparency, and we are keen to share the lessons learned in our pursuit towards net-zero energy housing. If you have ideas, knowledge or products that can help us deliver net-zero energy housing at an affordable price, we'd love to hear from you.