2,400+ Definitions
HVAC GLOSSARY
Every HVAC term, acronym, and industry phrase — defined in plain English.
Communicating Thermostat
A communicating thermostat uses digital signals to transmit real-time data…
Community Solar
Community solar is a shared solar energy system owned or…
Compound Gauge
A pressure gauge calibrated to read both positive pressures (in…
Compression Fitting
Compression fittings are mechanical connectors that seal a pipe by…
Compression Tank
A Compression Tank is a sealed hydronic system component that…
Compressor
The compressor is the heart of any refrigeration or HVAC…
Compressor Crankcase Heater
A compressor crankcase heater is a low-wattage electrical resistance heating…
Compressor Discharge Temperature
The temperature of refrigerant vapor at the compressor outlet, which…
Compressor Failure
Compressor failure occurs when the heart of the refrigeration system…
Compressor Megohm Test
An insulation resistance test performed with a megohmmeter on compressor…
Compressor Test
A compressor test evaluates the mechanical and electrical functionality of…
Compressor Unloading
A capacity-reduction mechanism in reciprocating or scroll chillers that disables…
Computer Room Air Conditioner
A Computer Room Air Conditioner (CRAC) is a specialized cooling…
Concealed Duct Indoor Unit
A fully ducted VRF or mini-split air handler intended for…
Concentrating Solar Collector
Concentrating solar collectors use mirrors or lenses to focus sunlight…
Concentric Vent
A concentric vent is a pipe-within-a-pipe configuration where the exhaust…
Conceptual Design
Conceptual Design is the preliminary HVAC planning phase where engineers…
Condensate Drain
The condensate drain system removes water that drips off the…
Condensate Drain Cleaning
Condensate drain cleaning removes blockages from the small pipe that…
Condensate Load
The volume or mass rate of liquid water that must…
Condensate Neutralizer
A condensate neutralizer is a chemical filtering device that treats…
Condensate Pan Cleaning
Condensate pan cleaning involves removing sediment, algae, and bacterial growth…
Condensate Pump
A small electric pump integrated into or added to a…
Condensation
Condensation is the phase change process where water vapor converts…
Condensation Resistance Factor
An NFRC index rated from 1 to 100 indicating a…
Condenser
The condenser is the outdoor unit of a split air…
Condenser Coil Cleaning
Condenser Coil Cleaning is the removal of dirt, pollen, debris,…
Condenser Fan
A condenser fan is an axial fan housed within the…
Condenser Fan Motor
A condenser fan motor is an electric motor mounted in…
Condenser Fouling Factor
A numerical resistance value representing the thermal insulating effect of…
Condenser Unit
A condenser unit is the outdoor component of a split-system…
Condenser Water Delta-T
The temperature rise of condenser water across a water-cooled chiller…
Condenser Water Supply Temperature Reset
A strategy that lowers condenser water setpoint toward the ambient…
Condensing Boiler
A high-efficiency boiler designed to extract latent heat from flue…
Condensing Furnace
A condensing furnace is a high-efficiency heating system that extracts…
Condensing Heat Exchanger
A secondary heat exchanger in a high-efficiency condensing furnace or…
Condensing Temperature
The saturation temperature of the refrigerant in the condenser at…
Condensing Unit
A self-contained outdoor or remote assembly consisting of a compressor,…
Conditioned Space
Conditioned space refers to building areas served by active heating…
Conduction
Conduction is the transfer of thermal energy through a material…
Conduction Time Series
A set of coefficients used in the radiant time series…
Conical Diffuser
A duct section that gradually expands in diameter to decelerate…
Connected HVAC
Connected HVAC refers to heating, ventilation, and air conditioning systems…
Conservation Voltage Reduction
Conservation Voltage Reduction (CVR) is a utility strategy that lowers…
Consortium for Energy Efficiency
The Consortium for Energy Efficiency (CEE) is a nonprofit organization…
Constant Air Volume
A Constant Air Volume (CAV) system is a type of…
Constant Torque Load
A constant torque load maintains consistent resistance regardless of motor…
Construction Documents
Construction Documents are comprehensive, final-phase drawings and specifications that contain…