HVAC Acronyms and Abbreviations

The Heating and Cooling industry aka HVAC or “Heating Ventilation and Air Conditioning” has a lot of acronyms and abbreviations.  You may hear an acronyms or abbreviation when looking into a new system, see the acronyms or abbreviation on a sticker or unit and wonder what that means.  We would like to help you with a list of related HVAC acronyms and abbreviations with links to other pages on our site to give even more information how the industry is using the term!  Hope this helps, if you have more questions about any of your Heating or Cooling needs in Maryland give us a call (410) 721-5595

  • A Air, Compressed Air, compressed air line, area
  • A/C Air conditioning
  • ABC Above ceiling
  • AC Air Conditioning air chamber, alternating current
  • ACDAutomatic Control Damper
  • ADAccess Door
  • AFAir Foil
  • AFF Above finished floor
  • AFG Above finished grade
  • AFUE Annual Fuel Utilization Efficiency
  • AHUAir Handling Unit
  • AL Aluminum
  • AMB Ambient
  • AMP Ampere
  • APAccess Panel
  • APDAir Pressure Drop
  • ARR Arrangement
  • ASAir Stream
  • ATCAutomatic Temperature Control
  • ATMAtmosphere
  • AUTO Automatic
  • AUX Auxiliary
  • AVG Average
  • B & S Bell and spigot
  • BBD Boiler blowdown
  • BDDBack-Draft Damper
  • BF Boiler feed
  • BHP Boiler horsepower, brake horsepower
  • BIBackwards Inclined
  • BODBottom of Duct
  • BOP Bottom of pipe
  • BOT Bottom
  • BP Back pressure
  • BSMT Basement
  • BTUBritish Thermal Unit
  • BTUHBritish Thermal Unit per Hour
  • BV Butterfly valve
  • C Condensate line
  • C to C Center to center
  • CA Compressed air
  • CAL Calorie
  • CAP Capacity
  • CD Condensate drain
  • CENTCenter, Centrifugal
  • CF Cubic Feet chemical feed, cubic foot
  • CFH Cubic feet per hour
  • CFMCubic Feet per Minute
  • CHChilled, Chiller
  • CHWChilled Water
  • CHWRChilled Water Return
  • CHWSChilled Water Supply
  • CI Cast iron
  • CIRC Circular
  • CL Center line
  • CM Centimeter
  • CM2 Square centimeter
  • COClean out, Carbon Monoxide
  • COL Column
  • CONC Concrete, concentric
  • CONNConnection, Connect
  • CONT Continuation
  • CPVC Chlorinated polyvinyl chloride
  • CR Condenser return
  • CRW Chemical resistant waste
  • CS Condenser supply
  • CTCooling Tower
  • CTBDCooling Tower Blow Down
  • CTR Center
  • CU Cubic
  • CU FT. Cubic feet
  • CU IN. Cubic inches
  • CUHCabinet Unit Heater
  • CV Check valve
  • CW Cold water
  • CWRCondenser Water Return, cold water riser
  • CWSCondenser Water Supply
  • DDrain, Deep
  • DBDry Bulb {Reference to Temperature}
  • DDCDirect Digital Control
  • DEGDegree
  • DELTAT Temperature difference, Delta Temperature
  • DET Detail
  • DIADiameter
  • DIMDimension
  • DISC Disconnect
  • DN Down
  • DPDifferential Pressure, Dew point temperature
  • DR Drain
  • DWG Drawing
  • E to C End to center
  • EAEach, Exhaust Air
  • EAHUExhaust Air Handling Unit
  • EATEntering Air Temperature
  • EATRExhaust Air Transfer Ratio
  • EER Energy efficient ratio
  • EFExhaust Fan
  • EFF Efficiency
  • EJ Expansion joint
  • EL Elevation
  • ELB Elbow
  • ELEC Electrical
  • EMEREmergency
  • EMSEnergy Management System
  • ENT Entering
  • ERVEnergy Recovery Ventilator
  • ESPExternal Static Pressure
  • ETExpansion Tank
  • EUHElectrical Unit Heater
  • EVAP Evaporator
  • EWTEntering Water Temperature
  • EXH / EXExhaust
  • EXPExpansion
  • EXST existing
  • EXTExternal
  • FFahrenheit
  • FAFree Area, Fire Alarm
  • FCFlexible Connection, flexible connection
  • FCO Floor clean out
  • FCUFan Coil Unit
  • FDFloor Drain, Fire Damper, Fire Department
  • FDW Feed water
  • FEC Fire extinguisher cabinet
  • FF Finish floor
  • FG Finish grade
  • FHC Fire hose cabinet
  • FLAFull Load Amps
  • FLEXFlexible
  • FLR Floor
  • FLRDRFloor Drain
  • FM Flow meter
  • FO Fuel oil
  • FOV Flush out valve
  • FPMFeet per Minute
  • FPSFeet per Second
  • FRPFiberglass Reinforced Plastic
  • FSFlow Switch, federal specs
  • FTFeet, Foot
  • FTG Fitting
  • FTRFin Tube Radiation
  • FU Fixture unit
  • FV Flush valve
  • GGas, Gram, gas line
  • GAGauge
  • GALGallons
  • GALVGalvanized
  • GFUGlycol Feed Unit
  • GL.V Globe valve
  • GND Ground
  • GPD Gallons per day
  • GPHGallons per Hour
  • GPMGallons per Minute
  • GPS Gallons per second
  • GRGrade, Grain
  • GV Gate valve
  • GWH Gas water heater
  • H2O Water
  • HBHose Bib (Connection)
  • HDHead
  • Hg Mercury
  • HGT Height
  • HMD Humidity
  • HORIZ Horizontal
  • HPHorsepower, High Point
  • HRHour
  • HRUHeat Recovery Unit
  • HRVHeat Recovery Ventilator
  • HTD Heated
  • HTGHeating
  • HTR Heater
  • HVACHeating Ventilation and Air Conditioning
  • HW Hot water
  • HWH Hot water heater
  • HWR Hot water return, hot water riser
  • HWS Hot water supply
  • HWT Hot water tank
  • HZHertz (Cycles per Second)
  • IDInside Diameter
  • INInches
  • IN. Inch
  • INHg Inches of mercury
  • INSUL Insulation
  • INT International
  • INTL Internal
  • IPS Iron pipe size
  • IV Indirect vent
  • IW Indirect waste
  • J Joule
  • K Kelvin
  • KG Kilogram
  • KM Kilometer
  • KM2 Kquare kilometer
  • KPA Kilo pascal
  • KS Kitchen sink
  • KWKilowatt
  • L Length, liter
  • LATLeaving Air Temperature
  • LBPound
  • LB. Pound
  • LBF Pound
  • LDLinear Diffuser
  • LFLinear Feet
  • LIQ Liquid
  • LPLow Point, Low Pressure
  • LRALocked Rotor Amps
  • LUVR / LVRLouver
  • LVDRLouvered Door
  • LVGLeaving
  • LVL Level
  • LVR Louver
  • LWTLeaving Water Temperature
  • M Meter
  • M TYPE Lightest type of rigid copper pipe
  • M2 Square meter
  • MAN Manual
  • MAT Mixed air temperature
  • MAXMaximum
  • MBH1000 BTUH, Thousand British thermal units per hour
  • MCAMinimum Circuit Amps
  • MECHMechanical
  • MFR Manufacturer
  • MG Milligram
  • MGD Millions gallons per day
  • MINMinimum, Minute
  • ML Milliliter
  • MM Millimeter
  • MM3 Cubic millimeter
  • MPT Male pipe thread
  • MTD Mounted
  • MU – Make-Up Water
  • MUA – Make-Up Air
  • NA Not applicable
  • NCNoise Criteria, Normally Closed
  • NEG Negative
  • NIC Not in contact
  • NONormally Open
  • NOMNominal
  • NPHP Name plate horsepower
  • NPS Nominal pipe size
  • NPSH Net positive suction head
  • NTS Not to scale
  • O Oxygen
  • OAOutside Air
  • OAIOutside Air Intake
  • OAT Outside temperature
  • OCOn Center
  • oC Degrees Celsius
  • ODOutside Diameter
  • ODPOpen Drip Proof
  • OED Open end duct
  • oF Degrees Fahrenheit
  • OF Overflow
  • OVOutlet Velocity
  • OZ. Ounce
  • PA Pascal
  • PC Plumbing contractor
  • PCFPounds per Cubic Foot
  • PCR Pumped condensate return
  • PDPressure Drop
  • PF Power factor
  • PG Pressure gauge
  • PHPhase
  • PL Plate
  • PNEU Pneumatic
  • PRESS Pressure
  • PROP Propeller
  • PRVPressure Reducing Valve
  • PSIPounds per Square Inch
  • PSIAPounds per Square Inch -Absolute
  • PSIDPounds per Square Inch -Differential
  • PSIGPounds per Square Inch -Gauge
  • PV Plug valve
  • PVCPolyvinyl Chloride
  • QTY Quantity
  • RRadius
  • R/E Return and exhaust
  • RAReturn Air
  • RAD Radius
  • RAT Return air temperature
  • RD Roof drain
  • RECOV Recovery
  • RED Reducer
  • REF Reference
  • REQD Required
  • RETReturn
  • REV Revision
  • RHRelative Humidity
  • RL Refrigerant liquid
  • RLARunning Load Amps, Rated Load Amperes
  • RLFRelief
  • RM Room
  • RPMRevolutions per Minute
  • RS Refrigerant suction
  • RTN Return
  • RTU – Roof-Top Unit
  • RV Relief valve
  • S Switch
  • SASupply Air, Shock absorber
  • SAT Supply air temperature
  • SCH Schedule
  • SCRScreen
  • SCTSaturated Condensing Temperature
  • SDSmoke Detector, Smoke Damper
  • SDT Saturated discharge temperature
  • SESmoke Exhaust
  • SEC Seconds, secondary
  • SEER Seasonal Energy Efficiency Ratio
  • SEN / SENSSensible
  • SEP Separate
  • SEQ Sequence
  • SER Series
  • SERV Service
  • SFSquare Feet, Service factor
  • SFDCombination Smoke / Fire Damper
  • SHCSensible Heat Capacity
  • SHT Sheet
  • SI International systems of units
  • SOL Solenoid
  • SPStatic Pressure
  • SPEC Specification
  • SPLY Supply
  • SQ. Square
  • SQ.FT. Square feet
  • SSStainless Steel
  • SSH Static suction head
  • SST Saturated suction temperature
  • STD Standard
  • STH Static total head
  • STL Steel
  • SUCT Suction
  • SUPSupply
  • SV Service
  • SVH Static velocity head
  • SW Service weight
  • SWS Service water
  • TTemperature, Thermostat
  • TD Temperature difference
  • TDH Total dynamic head
  • TEFCTotally Enclosed Fan Cooled
  • TEMPTemperature
  • TH Thermometer
  • THK Thick
  • TON12,000 BTUH {Cooling Capacity}
  • TP Total pressure
  • TSPTotal Static Pressure
  • TSTATThermostat
  • TYPTypical
  • UCUndercut {Door}
  • UF Under floor
  • UH Unit heater
  • VVolts, Vent, Volume
  • VAC Vacuum
  • VAVVariable Air Volume
  • VB Vacuum breaker
  • VCI Vacuum cleaning inlet
  • VCL Vacuum cleaning line
  • VDVolume Damper
  • VELVelocity
  • VERT Vertical
  • VFDVariable Frequency Drive
  • VIB Vibration
  • VOL Volume
  • VP Velocity pressure
  • VSD Variable speed drive
  • VTR Vent through roof
  • W Watt, width, wide
  • WBWet Bulb Temperature
  • WCWater Column
  • WCO Wall clean out
  • WGWater Gauge
  • WHWater heater
  • WPDWater Pressure Drop
  • WTDWater Temperature Difference

HVAC Acronyms and Abbreviations – Information

Knowing the acronyms and Abbreviations for HVAC terms can help you when deciding on a new system, an upgrade or understanding Air Conditioning or Furnace terms printed on you system.  We are glad to help with and questions you may have about Heating and Cooling systems.

HVAC repair and installation in Glen Burnie MD