I think the number one thing is building commissioning for existing buildings. Commissioning is really going in and optimizing all the systems, relooking at how they work together.
You build a building and it comes with a manual showing how it all works, but 35 years later, the tenants are configured differently, the number of occupants in the building is different, some of the systems have been changed and quite often you're still running it the way you were running it on day one. There's no right or wrong way to run a building, but there are ways that use more energy and ways that will use less energy.
There is a whole bunch of studies around different successes with building commissioning, where you might save 20% of your energy, in a good case, without changing any equipment, just changing the way that you actually run the building. I think things like that are low-hanging fruit. If we could do that across all of the buildings in Canada, there would be tremendous savings.