2,400+ Definitions
HVAC GLOSSARY
Every HVAC term, acronym, and industry phrase — defined in plain English.
Coil Suppression Device
A component such as a diode, metal oxide varistor, or…
Coincident Peak
Coincident peak refers to the maximum simultaneous electrical demand or…
Coincident Wet Bulb
The mean wet-bulb temperature statistically associated with a given dry-bulb…
Cold Aisle Containment
Cold aisle containment encloses the front of server racks to…
Cold Climate Heat Pump
An air-source heat pump specifically engineered with enhanced vapor injection,…
Cold Plasma
Cold plasma is an ionization technology that generates activated ions…
Cold Room
A cold room is an insulated, walk-in refrigerated space maintained…
Combi Boiler
A combi boiler is a single, compact unit that provides…
Combined Energy Efficiency Ratio
Combined Energy Efficiency Ratio (CEER) measures the cooling efficiency of…
Combined Heat and Power
Combined Heat and Power (CHP) refers to energy systems that…
Combustion Air
Combustion air is the oxygen-containing air required for the chemical…
Combustion Air Opening
A code-required opening or duct that supplies outdoor or unconfined…
Combustion Analysis
Combustion analysis is the process of measuring the byproducts of…
Combustion Analyzer
A combustion analyzer is an electronic instrument that measures exhaust…
Combustion Chamber
The combustion chamber is the enclosed space within a furnace…
Combustion Efficiency
A measure of how effectively a burner converts fuel energy…
Combustion Efficiency Tester
An instrument that calculates the percentage of fuel energy converted…
Combustion Inspection
A combustion inspection analyzes gas furnace combustion efficiency by measuring…
Combustion Safety
Combustion safety refers to the protection systems and practices that…
Combustion Safety Test
A combustion safety test is a comprehensive inspection measuring carbon…
Commercial Refrigeration
Commercial refrigeration encompasses all industrial-scale cooling systems designed to preserve…
Commercial Solar
Commercial solar systems are larger photovoltaic installations designed for businesses,…
Commercial Water Heater
Commercial water heaters are high-capacity systems designed to meet hot…
Commissioning
Commissioning is the systematic process of testing, adjusting, and documenting…
Commissioning Balancing
Commissioning balancing is the comprehensive process of measuring and adjusting…
Commissioning Checklist
A commissioning checklist is a comprehensive verification document ensuring all…
Commissioning Plan
A commissioning plan is a written document outlining the scope,…
Commissioning Report
A Commissioning Report documents the verification and testing results of…
Commissioning Specification
A Commissioning Specification is a detailed set of requirements that…
Common Mode Choke
An inductor wound so that differential mode motor current passes…
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…