Did you know that there is no heating and cooling machinery inside the bunker to support day-to-day operations? The Bunker relies on the geothermal system from the earth around it for heating and cooling.

Fun facts:

  • The coolest day of the year inside the Bunker on the 400 level/top level is in May/June. The temperature is between 19.5 – 21°C.
  • The warmest day of the year inside the Bunker on the 400 level/top level is in November/December. The temperature is between 25-26°C.
  • The hottest temperature recorded was 27.5°C – a few years ago in November.
  • When we took possession of the Bunker back in 1998, the temperature of the Bank of Canada Vault on the 100 level/bottom level was 7°C. Today, the Vault sits steadily around 13-14°C.

In the event of a nuclear attack or threat…

The Bunker was always prepared with a plan. In the event of a lockdown and the Bunker was at its full capacity (over 500 people), heating would have been reclaimed from general machinery and personnel. You read correctly — the plan was to use body heat!

Cooling would have been a bit more of a challenge. As a result, there was an air chiller in the Machine Room. This particular air chiller used Freon 12 – which is now illegal/banned due to the damage it caused the Ozone layer. Thankfully, there was never a nuclear attack and we never had to expell that Ozone depleteing gas into the atmosphere. 

The Bunker’s air chiller, not your typical A/C unit

The air chiller was drained of its Freon in 1995 and remains inside the Machine Room. Today, the Machine Room is still a vital part of the Diefenbunker and off-limits to visitors.

You are in luck though! You can take part in our specialty Machine Room tours on Father’s Day and during Archaeology Month in August. Sign up below to receive our Bunker eNewsletter and you’ll be the first to know when these tours are available.

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