2,400+ Definitions
HVAC GLOSSARY
Every HVAC term, acronym, and industry phrase — defined in plain English.
Sweat Fitting
Sweat fittings are soldered copper connections where solder metal flows…
Swimming Pool HVAC
Swimming pool HVAC systems manage temperature, humidity, and air quality…
System Commissioning
System commissioning is a quality-focused process for verifying and documenting…
System Curve Fan
A system curve is a graph representing the static pressure…
System Decommissioning
System decommissioning in HVAC refers to the planned, systematic process…
System Diagnosis
System diagnosis is the systematic evaluation of HVAC equipment performance…
System Flush
A system flush is the process of circulating a specialized…
System Selection
System Selection is the decision-making process for choosing the overall…
System Startup Checklist
A system startup checklist is a documented procedure verifying all…
System Weigh In
System Weigh In is a comprehensive verification process performed on…
Systems Manual
A Systems Manual is a comprehensive reference document that contains…
T S Diagram
A T-S (Temperature-Entropy) diagram is a thermodynamic chart that plots…
TAB Report
A TAB report is the formal documentation of airflow measurements,…
Tank Water Heater
A tank water heater stores heated water in an insulated…
Tankless Crossover
Tankless crossover is a plumbing configuration issue where hot water…
Tankless Water Heater
A tankless water heater heats water on demand without storage,…
Tankless Water Heater Flow Rate
Tankless water heater flow rate is the volume of water…
Tankless Water Heater GPM
Tankless water heater GPM (gallons per minute) rating specifies the…
Tape Lift Sample
Tape lift sampling is a quick, non-invasive method that uses…
Technician Certification
Technician Certification, mandated by EPA Section 608, is the professional…
TEFC Motor
TEFC (Totally Enclosed Fan-Cooled) Motor is a sealed motor design…
Temperature
Temperature is a fundamental physical property of matter that quantitatively…
Temperature Coefficient
Temperature coefficient quantifies how photovoltaic module performance changes with each…
Temperature Data Logger
A temperature data logger continuously records ambient or system temperatures…
Temperature Entropy Diagram
A temperature-entropy (T-S) diagram plots refrigerant properties with absolute temperature…
Temperature Pressure Relief Valve
A Temperature Pressure Relief (TPR) valve is a critical safety…
Temperature Rise Check
A temperature rise check measures the difference between return air…
Temperature Sensor
A temperature sensor is a device that detects and measures…
Temperature Split
Temperature split is the difference between return air temperature and…
Terminal Unit
A terminal unit is an HVAC component installed at or…
Test Adjust Balance
Test Adjust Balance (TAB) is the systematic process of measuring,…
TEWI
TEWI, or Total Equivalent Warming Impact, is a comprehensive metric…
Thermal Break
A thermal break is a low-conductivity material inserted between thermally…
Thermal Bridge
A thermal bridge is a pathway through insulation where heat…
Thermal Comfort
Thermal comfort is the condition of mind that expresses satisfaction…
Thermal Conductivity
Thermal conductivity is a material’s ability to conduct heat through…
Thermal Cutout
A thermal cutout is a non-resettable safety device that permanently…
Thermal Envelope
The thermal envelope is the boundary consisting of all building…
Thermal Expansion
Thermal expansion is the increase in water volume that occurs…
Thermal Imaging Inspection
Thermal imaging inspection uses specialized cameras to detect temperature variations…
Thermal Mass
Thermal mass is a building material’s capacity to absorb and…
Thermal Mass Effect
The thermal mass effect describes the ability of building materials…
Thermal Resistance
Thermal resistance, expressed as R-value, measures a material’s ability to…
Thermal Storage
Thermal storage is a system that captures and retains thermal…
Thermistor
A thermistor is a temperature-sensitive resistor that changes electrical resistance…
Thermocouple
A thermocouple is a temperature-sensing device that generates a small…
Thermocouple Meter
A thermocouple meter measures temperature using thermocouple probes, which generate…
Thermodynamic System
A thermodynamic system is a defined region of matter or…