The Sir John A. Macdonald Building was rehabilitated with environmental sustainability in mind.

The project is Green Globes certified and earned the highest possible eco-rating of five Green Globes. This designation, reserved for select building designs, is given to projects serving as national or world leaders in energy and environmental performance.

The building features the following green initiatives:

• Adaptive reuse of the main portion of the original Bank of Montreal Ottawa Head Office (1932 RAIC Gold Medal);
• Rehabilitation of a range of roust, historically significant materials and assemblies;
• Reuse of limestone and other materials to repair the masonry and refurbish the interior;
• Augmented and upgraded HVAC systems within the existing building including the Main Hall by introducing conditioned air within the occupied zone (lower 3.6m of 16.4m)
• Automated building control systems for ventilation, heating and cooling;
• A green roof with a variety of plants atop the annex to absorb rainwater, provide added insulation and reduce energy consumption and costs;
• Energy-efficient LED lights with sensors that turn off the lights when no one is in the office; and,
• Water-conserving features, such as new faucets and low-flush toilets.