HVAC/R Glossary

This glossary of HVAC and Refrigeration related abbreviations can help you navigate the most common terms you'll come across during your buying decision.

Acronym	What it stands for …
A		Back to Top
AC	Air Conditioning
AC	Alternating Current
ACH	Air Changes per Hour
ACM	Asbestos Containing Material
AEE	Association of Energy Engineers
AFD	Adjustable Frequency Drive
AFUE	Annual Fuel Efficiency Ratio
AHU	Air Handling Unit
AI	Analog Input
AO	Analog Output
ASHRAE	American Society of Heating Refrigeration and Air Conditioning Engineers
B		Back to Top
B	Boiler
BACnet	A Data Communication Protocol for Building Automation and Control Networks
BAS	Building Automation System
BCA	Building Commissioning Association
BI	Backward Incline
BI	Binary Input
BO	Binary Output
BSLN	Baseline
BTU	British Thermal Unit
BTUH	Brtish Thermal Units / Hour
BY	Base Year
C		Back to Top
CAV	Constant Air Volume
CD	Cold Deck
CDD	Cooling Degree Days
CEM	Certified Energy Manager
CFC	ChloroFluoroCarbon
CFM	Cubic Feet per Minute
CH	Chiller
CHW	Chilled Water
CHWP	Chilled Water Pump
CHWR	Chilled Water Return
CHWRT	Chilled Water Return Temperature
CHWS	Chilled Water Supply
CHWST	Chilled Water Supply Temperature
CLF	Cooling Load Factor
CLTD	Cooling Load Temperature Difference
COP	Coefficient Of Performance
CRAC	Computer Room Air Conditioner
CT	Cooling Tower
CV	Constant Volume
CVRMSE	Coefficient of Variation of the Root Mean Square of the Error
CWP	Condenser Water Pump
CWR	Condenser Water Return
CWRT	Condenser Water Return Temperature
CWS	Condenser Water Supply
CWST	Condenser Water Supply Temperature
CY	Current Year
D		Back to Top
DA	Discharge Air
DB	Data Base
DB	Dry Bulb
DC	Direct Current
DCV	Demand Controlled Ventilation
DD	Degree Day
DDC	Direct Digital Control
DH	Duct Heater
DI	Digital Input
DO	Digital Output
DP	Dew Point
DP	Differential Pressure
DX	Direct Expansion
E		Back to Top
EAT	Entering Air Temperature
ECM	Electronically Commutated Motor
ECM	Energy Conservation Measure
ECO	Energy Conservation Opportunity
EDH	Electric Duct Heater
EEM	Energy Efficiency Measure
EER	Energy Efficiency Ratio
EF	Exhaust Fan
EH	Electric Heater
EMS	Energy Management System
ESCO	Energy Service Company
EUH	Electric Unit Heater
EWT	Entering Water Temperature
F		Back to Top
FC	Forward Curve
FCU	Fan Coil Unit
FIM	Facility Improvement Measure
FLA	Full Load Amps
FMS	Facility Management System
FPM	Feet Per Minute
FW	Feed Water
G		Back to Top
GPM	Gallons Per Minute
GUI	Graphical User Interface
H		Back to Top
HCFC	Hydrochlorocfuorocarbon
HD	Hot Deck
HDD	Heating Degree Days
HEPA	High Efficiency Particulate Arresting
HFC	HydroFluoroCarbon
HHV	Higher Heating Value
HHWP	Heating Hot Water Pump
HHWR	Heating Hot Water Return
HHWS	Heating Hot Water Supply
HL	High Limit
HPS	High Pressure Steam
HR	Heat Recovery
HRU	Heat Recovery Unit
HRV	Heat Recovery Ventilator
HSPF	Heating Seasonal Performance Factor
HVAC	Heating Ventilation and Air Conditioning
HWP	Hot Water Pump
HWR	Hot Water Return
HWS	Hot Water Supply
HWRT	Hot Water Return Temperature
HWST	Hot Water Supply Temperature
HX	Heat Exchanger
I		Back to Top
I/O	Input Output
IAQ	Indoor Air Quality
IPMVP	International Performance Measurement and Verification Protocol
IR	Infra-Red
J		Back to Top
K		Back to Top
L		Back to Top
LAT	Leaving Air Temperature
LHV	Lower Heating Value
LL	Low Limit
LON	Local Operating Network
LP	Low Pressure
LPS	Low Pressure Steam
LRA	Locked Rotor Amps
LWBT	Leaving Wet Bulb Temperature
LWT	Leaving Water Temperature
M		Back to Top
M&V	Measurement and Verification
MA	Mixed Air
MAT	Mixed Air Temperature
MCC	Motor Control Center
MUA	Make-up Air Unit
MX	Metrix Utility Accounting System
MZ	Multi-Zone
N		Back to Top
NC	Normally Closed
NEMA	National Electrical Manufacturers Association
NO	Normally Open
NPSH	Net Positive Suction Head
O		Back to Top
OA	Outside Air
OAP	Outside Air Percentage
OAT	Outside Air Temperature
ODP	Open Drip Proof
OWS	Operator Work Station
P		Back to Top
PC	Performance Contracting
PE	Professional Engineer
PH	Pre-Heat
PID	Proportional Integral Derivative
PRV	Pressure Relief Valve
PRV	Pressure Reducing Valve
PTAC	Packaged Terminal Air Conditioner
Q		Back to Top
R		Back to Top
RA	Return Air
RF	Return Fan
RH	Reheat
RH	Relative Humidity
RPM	Revolutions Per Minute
RTD	Resistance Temperature Detector
RTU	Roof Top Unit
S		Back to Top
SA	Supply Air
SAT	Supply Air Temperature
SC	Shading Coefficient
SEER	Seasonal Energy Efficiency Ratio
SF	Supply Fan
SHFG	Solar Heat Gain Factor
SHR	Sensible Heat Ratio
SP	Set Point
SP	Static Pressure
SWP	Steam Working Pressure
T		Back to Top
T	Temperature
T	Thermostat
TEV	Thermostatic Expansion Valve
TOD	Time Of Day
TORR	Millimeter of Mercury (mmHg)
TXV	Thermostatic Expansion Valve
U		Back to Top
UH	Unit Heater
UV	UltraViolet
UV	Unit Ventilator
V		Back to Top
VAV	Variable Air Volume
VD	Volume Damper
VFD	Variable Frequency Drive
VSD	Variable Speed Drive
VSP	Variable Speed Pump(ing)
W		Back to Top
WB	Wet Bulb
WC	Water Column
X		Back to Top
Y		Back to Top
YTD	Year To Date
Z		Back to Top

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