Prepare your Building for Extreme Cold Weather

As many of you are aware, Chicagoland is forecasted to experience severe cold temperatures over the next week with lows occurring at or below zero with the forecasted overnight low on Christmas Eve being -4˚F.  The forecast projects temperatures that will test the limits of the heating capabilities of your equipment. In advance of this and other extreme cold weather events, it is important to make sure your building is prepared.

We recommend taking the following steps to ready your building for the extreme cold, especially if you have made changes to how your ventilation system is operating since last winter, or you have new space heating equipment:

  • Turn off all non-critical exhaust systems (i.e. residential kitchen and toilet exhaust)
  • Temporarily reduce ventilation where possible
    • DO NOT turn off 100% Makeup Air Units (MAUs)
      • If 100% MAUs shut down unexpectedly and cannot be restored, we advise shut down of the associated toilet and kitchen exhaust systems
    • Override unoccupied and overnight setbacks to occupied
    • Avoid scheduled shutdowns of systems
    • Avoid turning heating related equipment off
    • Verify all coil pumps are operational
      • DO NOT shut coil pumps off
    • Maintain continuous operation of all heating related pumps
    • Minimize infiltration
      • Keep doors, windows and other openings sealed
      • Add temporary heat where infiltration can’t be controlled or where you have observed cold temperatures in the past
    • Keep blinds and shades closed on windows at night and those not receiving direct sunlight during the day
    • Perform a system check of all heating critical equipment
    • Verify the operation of all low-limit safeties such as freezestats to protect equipment
      • Ensure the sequence of operation is followed upon a freezestat trip (Example: outside air dampers properly shut and can be reopened)
    • Test the operation of all backup or redundant heating equipment and sequences not normally used
    • Verify the location of isolation valves, verify their operation and understand when to use them
      • During an emergency situation where a pipe, coil or other system has frozen, the reliability, and proper use of isolation valves is critical
      • Isolate the leak to as local an area as possible.
      • Take care not to close the wrong valve (essentially stopping the flow of water)
        • Water at rest is much more likely to freeze.  Therefore, do not risk further freezing of the system by closing the wrong valve, should isolation be required
  • To the extent possible, remove ice and snow from air-source heating equipment such as VRF and air-source heat pumps
    • Also remove snow from the areas immediately surrounding the equipment

For more information or to address specific concerns or questions, please contact us at

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