HVAC Definitions Terms & Acronyms | Heating Cooling - This is a comprehensive list of HVAC Acronyms and HVAC Terms. High Performance HVAC is certain there are more terms and acronyms. If you know of something we missed please email us. Thanks!

HVAC Definitions Terms & Acronyms

HVAC Definitions Terms & Acronyms - VSD or Variable Speed Drives

VSD or Variable Speed Drives

AC – Air Conditioning or Alternating Current

ACCA – Air Conditioning Contractors Associations

AFUE – Annual Fuel Utilization Efficiency

AHU – Air Handling Unit

AI – Analog Input

AMCA – Air Movement and Control Association

AO – Analog Output

AQS – Air Quality Systems

ASHRAE – American Society of Heating, Refrigerating, and Air Conditioning Engineers

AV – Automatic Air Vent

AWG – American Wire Gage

B – Boiler

BACnet – Computer communication protocol for building automation systems and control networks

BAS – Building Automation System

BI – Binary Input

BMS – Building Management System

BO – Binary Output

BP – Backflow Preventer

BTU – British Thermal Unit

BTUh – Brtish Thermal Units per Hour

HVAC Definitions Terms & Acronyms

CAV – Constant Air Volume

CD – Cold Deck (also Condensation Drain)

CFC – ChloroFluoroCarbon

CFM – Cubic Feet per Minute

CHR – Chilled Water Return (can also have an S in front of the acronym which stands for Secondary when secondary water loops have secondary loops)

CHS – Chilled Water Supply (can also have an S in front of the acronym which stands for Secondary when secondary water loops have secondary loops)

CHWP – Chilled Water Pump (can also have an S in front of the acronym which stands for Secondary when secondary water loops have secondary loops)

CHWR – Chilled Water Return (can also have an S in front of the acronym which stands for Secondary when secondary water loops have secondary loops)

CHWS – Chilled Water Supply (can also have an S in front of the acronym which stands for Secondary when secondary water loops have secondary loops)

CO – Clean Out (also Carbon Monoxide)

COP – Coefficienct of Performance

CRAC – Computer Room Air Conditioner

CRAH – Computer Room Air Handler

CSR – Capacitor Start Capacitor Run

CV – Constant Volume

CWP – Condenser Water Pump

CWR – Condenser Water Return

CWS – Condenser Water Supply

HVAC Definitions Terms & Acronyms

DA – Discharge Air or Direct Acting

DAT – Discharge Air Temperature

DB – Dry Bulb or Dead Band

DC – Direct Current

DCBP – Double Check Backflow Preventer

DD – Degree Day

DDC – Direct Digital Control

DI – Digital Input

DO – Digital Output

DP – Differential Pressure

DPDT – Double Pole Double Throw

DPST – Double Pole Single Throw

DSI – Direct Spark ignition

DX – Direct Expansion

 

EDR – Equivalent Direct Radiation

EER – Energy Efficiency Ratio

EMF – Electromotive Force

EF – Exhaust Fan

EMCS – Energy Management Control System

EMS – Energy Management System

EP – Electric to Pneumatic

ERV – Energy Recovery Ventilator

EXV – Electronic Expansion Valve

 

FA – Fire Alarm

FAI – Fresh Air Intake

FCU – Fan Coil Unit

FD – Fire Damper

FLA – Full Load Amps

FPM – Feet Per Minute

FPVAV – Fan Powered Variable Air Volume Box

FS – Float Switch

F & T – Float & Thermostatic

HVAC Definitions Terms & Acronyms

GPM – Gallons per Minute

GWP – Global Warming Potential

HEPA – High-Efficiency Particulate Arresting

HCFC – HydroChloroFluoroCarbon

HD – Hot Deck

HFC – HydroFluoroCarbon

HOA – Hand Off Auto

HP – High Pressure or Horse Power

HPS – High-Pressure Steam

HRU – Heat Recovery Unit

HRV – Heat Recovery Ventilator

HSI – Hot Surface Ignition

HSPF – Heating Seasonal Performance Factor

HSTAT – Humidistat

HVAC – Heating, Ventilation, & Air Conditioning

HVAC&R – Heating, Ventilation, Air Conditioning, & Refrigeration

HWP – Hot Water Pump

HWR – Hot Water Return (can also have an S in front of the acronym which stands for Secondary when hot water loops have secondary loops)

HWS – Hot Water Supply (can also have an S in front of the acronym which stands for Secondary when hot water loops have secondary loops)

HWUH – Hot Water Unit Heater

HX – Heat Exchanger

HZ – Hertz
I/O – Input/Output

IAQ – Indoor Air Quality

IMC – International Mechanical Code

in. Hg – inches of mercury vacuum

in. WC – inches of Water Column

IRH – InfraRed Heater

JB – Junction Box

KO – Knock Out

KW – Kilowatts

HVAC Definitions Terms & Acronyms

LL – Low Limit

LP – Low Pressure or Liquified Petroleum

LPS – Low-Pressure Steam

LRA – Locked Rotor Amps

LWCO – Low Water Cut Off

 

MA – Mixed Air

MAT – Mixed Air Temperature

MAU – Makeup Air Unit

MCC – Motor Control Center

MFD – Micro-Farad

MP – Motor Protector

MPT – Male Pipe Thread

MUW – Make-up Water

MV – Manual Air Vent

NC – Normally Closed

NEC – National Electric Code

NFPA – National Fire Protection Association

NO – Normally Open

NPT – National Pipe Thread

NTC – Negative Temperature Coefficient

 

OA – Outside Air

OAT – Outside Air Temperature

OP – Oil Pressure

ODP – Ozone Depletion Potential

 

PCB – Printed Circuit Board

PE – Pneumatic to Electric

PID – Proportional, Integral, & Derivative

PRV – Pressure Reducing Valve

PSC – Permanent Split Capacitor

PSIA – Pounds per Square Inch Absolute

PSIG – Pounds per Square Inch Gauge

PT – Pressure Temperature

PTAC – Portable Terminal Air Conditioner

PTC – Positive Temperature Coefficient

PWM – Pulse Width Modulation

HVAC Definitions Terms & Acronyms

RA – Return Air or Reverse Acting

RAT – Return Air Temperature

RF – Return Fan

RH – Relative Humidity

RPBP – Reduced Pressure Backflow Preventer (sometimes also seen as RPZ)

RPM – Revolutions Per Minute

RTU – Roof Top Unit

RV – Reversing Valve

 

SA – Supply Air

SAT – Supply Air Temperature

SCADA – Supervisory Control and Data Acquisition

SD – Smoke Damper

SEER – Seasonal Energy Efficiency Ratio

SF – Service Factor or Supply Fan

SH – Super Heat

SMACNA – Sheet Metal and Air Conditioning Contractors National Association

SP – Static Pressure or Set Point

SPDT – Single Pole Double Throw

SPST – Single Pole Single Throw

SV – Solenoid Valve

 

TD – Temperature Difference or Time Delay

TDS – Total Dissolved Solids

TH – Thermometer in a Thermowell

TEV – Thermostatic Expansion Valve (sometimes also seen as TXV)

Ton – ton of refrigeration effect

TSTAT – Thermostat

 

UH – Unit Heater

UMC – Uniform Mechanical Code

UV – Ultra-Violet or Unit Ventilator

 

VAV – Variable Air Volume

VFD – Variable Frequency Drive

VSD – Variable Speed Drive

VVT – Variable Volume/Temperature

 

W – Watt

WB – Wet Bulb

WC – Water Column

 

XFMR – Transformer

 

ZD – Zone Damper

Additional resources for HVAC can be found here.

 

High Performance HVAC

HVAC Definitions Terms & Acronyms

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