2,400+ Definitions
HVAC GLOSSARY
Every HVAC term, acronym, and industry phrase — defined in plain English.
Thermocouple Vacuum Gauge
A vacuum gauge that measures pressure by detecting the temperature…
Thermodynamic System
A thermodynamic system is a defined region of matter or…
Thermodynamic Wet-Bulb Temperature
The temperature a parcel of air would reach if cooled…
Thermodynamics
Thermodynamics is the branch of physics that deals with the…
Thermoelectric Cooling
Thermoelectric cooling uses electrical current flowing through semiconductor materials to…
Thermopile
A thermopile is a series of thermocouples connected in sequence…
Thermosiphon Heat Recovery
Thermosiphon heat recovery uses natural convection to circulate a heat…
Thermosiphon System
A thermosiphon system is a passive solar water heating method…
Thermostat
A thermostat is the control device that monitors indoor temperature…
Thermostat Calibration
Thermostat calibration adjusts the internal temperature sensor so that displayed…
Thermostat Installation
Thermostat installation is the process of mounting a temperature control…
Thermostat Wiring
Thermostat wiring connects low-voltage control circuits between the thermostat, furnace,…
Thermostatic Expansion Valve
A thermostatic expansion valve (TXV) is a precision refrigerant metering…
Thin Film Solar Panel
A thin film solar panel uses ultra-thin semiconductor layers (1-2…
Thin-Slab Radiant
A radiant floor system where tubing is embedded in a…
Thread Protocol
Thread is a low-power mesh networking protocol built on 802.15.4…
Three Phase
Three-phase power consists of three alternating current circuits carrying the…
Three Way Valve
A three-way valve has three ports that either mix two…
Throttling Range
The range of the controlled variable over which a proportional…
Through Wall AC
A through-wall air conditioner is a self-contained cooling unit that…
Tiered Rate
Tiered rate structures charge progressively higher per-kilowatt-hour rates as monthly…
Tilt Mount Solar
Tilt mount solar systems position photovoltaic panels at adjustable angles…
Time Delay Relay
A time delay relay is an electrical component that introduces…
Time Lag
The delay in hours between the peak outdoor temperature and…
Time of Use Optimization
Time of use optimization is the strategic management of electricity…
Time of Use Rate
A time of use (TOU) rate is a utility billing…
Title 24
Title 24 refers to the energy efficiency standards established under…
TMY Data
TMY (Typical Meteorological Year) data is a 12-month synthetic weather…
Toluene
Toluene is a volatile organic compound widely used in paints,…
Ton
A ton of refrigeration is a unit of power used…
Ton (HVAC)
In HVAC, a ton is a unit of cooling capacity…
Toroidal Transformer
A transformer wound on a donut-shaped ferromagnetic core that produces…
Torque Check
A torque check verifies that all mechanical fasteners and mounting…
Total Energy Recovery Efficiency
A combined measure of both sensible and latent heat transfer…
Total Energy Wheel
A total energy wheel, also called an enthalpy wheel, transfers…
Total Equivalent Warming Impact
Total Equivalent Warming Impact (TEWI) is a metric that quantifies…
Total External Static Pressure
Total external static pressure (TESP) is the combined static pressure…
Total Heat
The sum of sensible and latent heat in an air-conditioning…
Total Volatile Organic Compounds
Total volatile organic compounds (TVOCs) is the combined concentration of…
Trane Trace
Trane Trace is a comprehensive whole-building energy modeling software developed…
Transcritical CO2
Transcritical CO2 operation occurs when the refrigerant pressure exceeds the…
transcritical cycle
A refrigeration cycle in which the high-side pressure exceeds the…
Transfer Grille
A transfer grille is an opening with a fixed or…
Transformer
A transformer is an electrical device that converts high-voltage power…
Transformer VA Rating
The apparent power rating of a transformer expressed in volt-amperes,…
Transient State
Transient state describes system conditions where properties change with time…
Trend Analysis BAS
Trend analysis in Building Automation Systems (BAS) is the examination…
Trend Log
A BAS function that records time-stamped values of selected analog…