| abbrev | define |
|---|---|
| A | Air or Compressed Air |
| AC | Air Conditioning or Alternating Current |
| ACCA | Air Conditioning Contractors Associations |
| ACD | Automatic Control Damper |
| ACH | Air Changes per Hour |
| ACM | Asbestos Containing Material |
| AD | Access Door |
| AEE | Association of Energy Engineers |
| AF | Air Foil |
| AFD | Adjustable Frequency Drive |
| AFUE | Annual Fuel Utilization Efficiency |
| AHU | Air Handling Unit |
| AI | Analog Input |
| AMCA | Air Movement and Control Association |
| AMP | Ampere |
| AO | Analog Output |
| AP | Access Panel |
| APD | Air Pressure Drop |
| AQS | Air Quality Systems |
| AS | Air Stream |
| ASHRAE | American Society of Heating, Refrigerating and Air Conditioning Engineers |
| ATC | Automatic Temperature Control |
| ATM | Atmosphere |
| AV | Automatic Air Vent |
| AWG | American Wire Gage |
| B | Boiler |
| BACnet | A Data Communication Protocol for Building Automation and Control Networks |
| BAS | Building Automation System |
| BCA | Building Commissioning Association |
| BDD | Back-Draft Damper |
| BHP | Brake Horsepower |
| BI | Backward Incline or Binary Input |
| BMS | Building Management System |
| BO | Binary Output |
| BOD | Bottom of Duct |
| BP | Backflow Preventer |
| BSLN | Baseline |
| BTU | British Thermal Unit |
| BTUH | Brtish Thermal Units / Hour |
| BY | Base Year |
| CAV | Constant Air Volume |
| CD | Cold Deck (also Condensation Drain) |
| CDD | Cooling Degree Days |
| CEM | Certified Energy Manager |
| CENT | Center or Centrifugal |
| CF | Cubic Feet |
| CFC | ChloroFluoroCarbon |
| CFM | Cubic Feet per Minute |
| CH | Chilled or Chiller |
| CHR | Chilled Water Return |
| CHS | Chilled Water Supply |
| 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 |
| CO | Carbon Monoxide or Clean Out |
| CONN | Connection |
| COP | Coefficient Of Performance |
| CRAC | Computer Room Air Conditioner |
| CRAH | Computer Room Air Handler |
| CSR | Capacitor Start Capacitor Run |
| CT | Cooling Tower |
| CTBD | Cooling Tower Blow Down |
| CUH | Cabinet Unit Heater |
| 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 | Drain |
| DA | Discharge Air or Direct Acting |
| DAT | Discharge Air Temperature |
| DB | Dry Bulb (Temperature) or Dead Band |
| DC | Direct Current |
| DCBP | Double Check Backflow Preventer |
| DCV | Demand Controlled Ventilation |
| DD | Degree Day |
| DI | Digital Input |
| DIA | Diameter |
| DIM | Dimension |
| DO | Digital Output |
| DP | Dew Point or Differential Pressure |
| DPDT | Double Pole Double Throw |
| DPST | Double Pole Single Throw |
| DSI | Direct Spark ignition |
| DX | Direct Expansion |
| EA | Each or Exhaust Air |
| EAHU | Exhaust Air Handling Unit |
| EAT | Entering Air Temperature |
| ECM | Electronically Commutated Motor or Energy Conservation Measure |
| ECO | Energy Conservation Opportunity |
| EDH | Electric Duct Heater |
| EDR | Equivalent Direct Radiation |
| EEM | Energy Efficiency Measure |
| EER | Energy Efficiency Ratio |
| EF | Exhaust Fan |
| EH | Electric Heater |
| EMCS | Energy Management Control System |
| EMER | Emergency |
| EMF | Electromotive Force |
| EMS | Energy Management System |
| EP | Electric to Pneumatic |
| ERV | Energy Recovery Ventilator |
| ESCO | Energy Service Company |
| ESP | External Static Pressure |
| ET | Expansion Tank |
| EUH | Electrical Unit Heater |
| EWT | Entering Water Temperature |
| EXH or EX | Exhaust |
| EXP | Expansion |
| EXT | External |
| EXV | Electronic Expansion Valve |
| F | Fahrenheit |
| F & T | Float & Thermostatic |
| FA | Free Area or Fire Alarm |
| FAI | Fresh Air Intake |
| FC | Forward Curve or Flexible Connection |
| FCU | Fan Coil Unit |
| FD | Floor Drain, Fire Damper, or Fire Department |
| FIM | Facility Improvement Measure |
| FLA | Full Load Amps |
| FLEX | Flexible |
| FLRDR | Floor Drain |
| FMS | Facility Management System |
| FPM | Feet Per Minute |
| FPS | Feet per Second |
| FPVAV | Fan Powered Variable Air Volume Box |
| FRP | Fiberglass Reinforced Plastic |
| FS | Flow Switch |
| FT | Feet |
| FTR | Fin Tube Radiation |
| FW | Feed Water |
| G | Gas |
| GA | Gauge |
| GAL | Gallons |
| GALV | Galvanized |
| GFU | Glycol Feed Unit |
| GPH | Gallons per Hour |
| GPM | Gallons Per Minute |
| GR | Grade |
| GUI | Graphical User Interface |
| GWP | Global Warming Potential |
| HB | Hose Bib (Connection) |
| HCFC | HydroChloroFluoroCarbon |
| HD | Head or 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 |
| HOA | Hand Off Auto |
| HP | High Pressure or Horse Power or High Point |
| HPS | High Pressure Steam |
| HR | Heat Recovery or Hour |
| HRU | Heat Recovery Unit |
| HRV | Heat Recovery Ventilator |
| HSI | Hot Surface Ignition |
| HSPF | Heating Seasonal Performance Factor |
| HSTAT | Humidistat |
| HTG | Heating |
| HVAC | Heating, Ventilation & Air Conditioning |
| HVAC&R | Heating, Ventilation, Air Conditioning & Refrigeration |
| HWP | Hot Water Pump |
| HWR | Hot Water Return |
| HWRT | Hot Water Return Temperature |
| HWS | Hot Water Supply |
| HWST | Hot Water Supply Temperature |
| HWUH | Hot Water Unit Heater |
| HX | Heat Exchanger |
| HZ | Hertz (Cycles per Second) |
| I/O | Input Output |
| IAQ | Indoor Air Quality |
| ID | Inside Diameter |
| IMC | International Mechanical Code |
| IN | Inches |
| in. Hg | inches of mercury vacuum |
| in. WC | inches of Water Column |
| IPMVP | International Performance Measurement and Verification Protocol |
| IR | Infra-Red |
| IRH | InfraRed Heater |
| JB | Junction Box |
| KO | Knock Out |
| KW | Kilowatt |
| LAT | Leaving Air Temperature |
| LB | Pound |
| LD | Linear Diffuser |
| LF | Linear Feet |
| LHV | Lower Heating Value |
| LL | Low Limit |
| LON | Local Operating Network |
| LP | Low Pressure or Liquified Petroleum |
| LPS | Low-Pressure Steam |
| LRA | Locked Rotor Amps |
| LUVR or LVR | Louver |
| LVDR | Louvered Door |
| LVG | Leaving |
| LWBT | Leaving Wet Bulb Temperature |
| LWCO | Low Water Cut Off |
| LWT | Leaving Water Temperature |
| M&V | Measurement and Verification |
| MA | Mixed Air |
| MAT | Mixed Air Temperature |
| MAU | Makeup Air Unit |
| MAX | Maximum |
| MBH | 1000 BTUH |
| MCA | Minimum Circuit Amps |
| MCC | Motor Control Center |
| MECH | Mechanical |
| MFD | Micro-Farad |
| MIN | Minimum |
| MP | Motor Protector |
| MPT | Male Pipe Thread |
| MU | Make-Up Water |
| MUA | Make-Up Air |
| MUW | Make-up Water |
| MV | Manual Air Vent |
| MX | Metrix Utility Accounting System |
| MZ | Multi-Zone |
| NC | Noise Criteria or Normally Closed |
| NEC | National Electric Code |
| NEMA | National Electrical Manufacturers Association |
| NFPA | National Fire Protection Association |
| NO | Normally Open |
| NOM | Nominal |
| NPSH | Net Positive Suction Head |
| NPT | National Pipe Thread |
| NTC | Negative Temperature Coefficient |
| OA | Outside Air |
| OAI | Outside Air Intake |
| OAP | Outside Air Percentage |
| OAT | Outside Air Temperature |
| OC | On Center |
| OD | Outside Diameter |
| OP | Oil Pressure |
| OV | Outlet Velocity |
| OWS | Operator Work Station |
| PC | Performance Contracting |
| PCB | Printed Circuit Board |
| PCF | Pounds per Cubic Foot |
| PD | Pressure Drop |
| PE | Professional Engineer or Pneumatic to Electric |
| PH | Pre-Heat or Phase |
| PID | Proportional, Integral & Derivative |
| PRV | Pressure Relief Valve or Pressure Reducing Valve |
| PSC | Permanent Split Capacitor |
| PSI | Pounds per Square Inch |
| PSIA | Pounds per Square Inch – Absolute |
| PSID | Pounds per Square Inch – Differential |
| PSIG | Pounds per Square Inch – Gauge |
| PT | Pressure Temperature |
| PTAC | Packaged Terminal Air Conditioner |
| PTC | Positive Temperature Coefficient |
| PVC | Polyvinyl Chloride |
| PWM | Pulse Width Modulation |
| R | Radius |
| RA | Return Air or Reverse Acting |
| RAT | Return Air Temperature |
| RET | Return |
| RF | Return Fan |
| RH | Relative Humidity or Reheat |
| RLA | Running Load Amps |
| RLF | Relief |
| RPBP | Reduced Pressure Backflow Preventer (sometimes also seen as RPZ) |
| RPM | Revolutions Per Minute |
| RTD | Resistance Temperature Detector |
| RTU | Roof Top Unit |
| RV | Reversing Valve |
| SA | Supply Air |
| SAT | Supply Air Temperature |
| SC | Shading Coefficient |
| SCADA | Supervisory Control and Data Acquisition |
| sCHR | Secondary Chilled Water Return |
| sCHS | Secondary Chilled Water Supply |
| sCHWP | Secondary Chilled Water Pump |
| sCHWR | Secondary Chilled Water Return |
| sCHWS | Secondary Chilled Water Supply |
| SCR | Screen |
| SCT | Saturated Condensing Temperature |
| SD | Smoke Detector or Smoke Damper |
| SE | Smoke Exhaust |
| SEER | Seasonal Energy Efficiency Ratio |
| SEN | Sensible |
| SF | Service Factor or Supply Fan |
| SFD | Combination Smoke / Fire Damper |
| SH | Super Heat |
| SHC | Sensible Heat Capacity |
| SHFG | Solar Heat Gain Factor |
| SHR | Sensible Heat Ratio |
| sHWR | Secondary Hot Water Return |
| sHWS | Secondary Hot Water Supply |
| 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 |
| SS | Stainless Steel |
| SUP | Supply |
| SV | Solenoid Valve |
| SWP | Steam Working Pressure |
| T | Temperature or Thermostat |
| TD | Temperature Difference or Time Delay |
| TDS | Total Dissolved Solids |
| TEFC | Totally Enclosed Fan Cooled |
| TEMP | Temperature |
| TEV | Thermostatic Expansion Valve (sometimes also seen as TXV) |
| TH | Thermometer in a Thermowell |
| TOD | Time Of Day |
| TON | 12,000 BTUH (Cooling Capacity) or ton of refrigeration effect |
| TORR | Millimeter of Mercury (mmHg) |
| TSP | Total Static Pressure |
| TSTAT | Thermostat |
| TXV | Thermostatic Expansion Valve |
| TYP | Typical |
| UC | Undercut (Door) |
| UH | Unit Heater |
| UMC | Uniform Mechanical Code |
| UV | Ultra-Violet or Unit Ventilator |
| V | Volts |
| VAV | Variable Air Volume |
| VD | Volume Damper |
| VEL | Velocity |
| VFD | Variable Frequency Drive |
| VSD | Variable Speed Drive |
| VSP | Variable Speed Pump(ing) |
| VVT | Variable Volume/Temperature |
| W | Watt |
| WB | Wet Bulb Temperature |
| WC | Water Column |
| WG | Water Gauge |
| WPD | Water Pressure Drop |
| WTD | Water Temperature Difference |
| XFMR | Transformer |
| YTD | Year To Date |
| ZD | Zone Damper |