HVAC Plan Symbols

Each mechanical engineering office uses their own set of HVAC symbols; however, the symbols below are fairly common across most mechanical drawings.  Refer to the symbol legend sheet for special symbols used in a particular set. You may also be interested in reviewing HVAC abbreviations that are typically used in drawings.

Supply and Return Airflow Symbols

Standard 4-Way Ceiling Supply Diffuser

Standard 4-Way Blow Diffuser symbol

3-Way Ceiling Supply Diffuser

3-Way Blow Diffuser symbol

2-Way Ceiling Supply Diffuser

2-Way Blow Diffuser symbol

1-Way Ceiling Supply Diffuser

1-Way Blow Diffuser symbol

Return Grille (Exhaust)

Return Grille Symbol

Direction of Supply Air

Direction of Supply Air symbol

Direction of Return Air

Direction of Return Air symbol

Door Undercut Size

Door Undercut symbol

Door Louver with Clear Area

Door Louver symbol with Clear Area notation

HVAC Damper Symbols

Volume Damper

Volume Damper symbol

Fire Damper

Fire Damper symbol

Smoke Damper

Smoke Damper symbol

Combination Smoke and Fire Damper

Combination Smoke and Fire Damper symbols

Back-draft Damper

Back-draft Damper symbol

HVAC Piping Symbols

Chilled Water Supply

Chilled Water Supply line symbol

Chilled Water Return

Chilled Water Return line symbol

Hot Water Supply

Hot Water Supply line symbol

Hot Water Return

Hot Water Return line symbol

Vent Pipe

Vent Pipe line symbol

Drain Pipe

Drain Pipe line symbol

Make-Up Water Pipe

Make-Up Water Pipe line symbol

HVAC Sensor Symbols


Thermostat symbol

Humidity Sensor

Humidity Sensor symbol

Article Updated: May 6, 2021

Help make Archtoolbox better for everyone. If you found an error or out of date information in this article (even if it is just a minor typo), please let us know.

Subscribe to the Archtoolbox Newsletter

Receive a curated email with industry news focusing on practice, leadership, technology, and career growth.

* indicates required