On Monday, March 20, 2023, passersby may have noticed a sky-high crane at our site lifting large equipment along the bunker hillside. We are eager to share a behind-the-scenes look at this major capital project for the Diefenbunker.

Due to generous funding we have received through the Investing in Canada Infrastructure Program (ICIP): Community, Culture and Recreation Infrastructure Stream, we have been able to make huge strides over the last few years towards upgrading critical infrastructure within the museum to ensure the preservation of this unique Cold War artifact. We are grateful to the Government of Canada and the Government of Ontario for funding a heating, ventilation, and air conditioning (HVAC) project.

Through this project, we have pursued necessary upgrades to the bunker’s aging air ventilation system. Upgrades to this 60-year-old system were required in order to improve temperature and humidity control and air flow. A new HVAC system will allow us to bring clean, demand-controlled, and conditioned air into the building.  

The Diefenbunker has been working closely with engineering firm Morrison Hershfield and contractor Modern Niagara to install a makeup air handling unit. The purpose of this unit is to bring in fresh, tempered air from outside which is then heated to room temperature and used to replenish the existing air that cannot be recirculated. The conditioned air is distributed via the ductwork, while the existing air is removed from the building through exhaust fans. The makeup air handling unit also helps to equalize pressure throughout the building. With the aid of the 197 foot crane, this installation was done as non-invasively as possible in order to maintain the building’s historical integrity. Other important work with associated duct and ventilation systems is being done to integrate the new equipment with existing functional systems in the bunker’s Machine Room. With the diligent assistance of our engineering firm and contractor, we have been able to document all changes being made to the bunker for historical purposes.

Other projects this funding has afforded the museum are upgrades to our washrooms, including installing a second accessible washroom; critical electrical upgrades; the installation of accessible lift devices in our main stairwell; and an automatic door opener at our front entrance to increase the museum’s accessibility for visitors.

We anticipate the completion of this important HVAC project this spring, providing our staff and visitors with improved air quality and climate control throughout the museum.



Crane carries a condenser unit, an outdoor part of an air conditioning system that is responsible for ejecting heat outside, to the top of the bunker.

Contractors install a direct expansion (DX) coil on top of the bunker that will be used to cool and/or remove moisture from the air inside the facility.








Newly installed fans inside the makeup air handling unit in the bunker’s Machine Room.

Ventilation system in the process of being installed in the bunker’s Machine Room.

New duct work system that seals the intake duct, allowing conditioned air to be brought in to the bunker from outside.






We acknowledge the financial support of the Government of Canada and the Government of Ontario.


Learn more about our recent projects:

Green Infrastructure Lighting Retrofit Project

Two new permanent exhibitions

Blast Tunnel Experience

Virtual Reality Experience


Book Now