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