2,400+ Definitions
HVAC GLOSSARY
Every HVAC term, acronym, and industry phrase — defined in plain English.
C Wire Installation
C wire installation adds a continuous 24-volt return path to…
Cabinet Unit Heater
A cabinet unit heater is a self-contained heating appliance that…
California Energy Code
The California Energy Code, formally known as Title 24 Part…
California Title 20
California Title 20 refers to the appliance efficiency regulations established…
California Title 24
California Title 24 is the state’s energy code that establishes…
California Title 24 2022
California Title 24-2022 represents the state’s latest building energy efficiency…
Capacitance Hygrometer
A humidity sensor that measures relative humidity by detecting changes…
Capacitor
A capacitor is an electrical component that stores electrical charge…
Capacitor Bank
A capacitor bank is an assembly of multiple capacitors electrically…
Capacitor ESR
Equivalent Series Resistance is the real resistive component of a…
Capacitor Failure
Capacitor failure occurs when the electrical storage component loses its…
Capacitor Test
A capacitor test measures the microfarad (µF) rating and electrical…
Capacity Ratio
The ratio of total connected indoor unit nominal capacity to…
Capillary Action in Brazing
The phenomenon by which molten brazing alloy is drawn into…
Capillary Tube
A capillary tube is a fixed-length, narrow-bore tube used as…
Carbon Accounting
Carbon Accounting is the systematic process of quantifying, tracking, and…
Carbon Dioxide
Carbon dioxide (CO2) is a colorless, odorless gas naturally present…
Carbon Emissions
Carbon Emissions represent the volume of carbon dioxide (CO2) and…
Carbon Free Energy
Carbon Free Energy is electricity generated without producing carbon dioxide…
Carbon Monoxide
Carbon monoxide (CO) is a toxic, odorless, colorless gas produced…
Carbon Monoxide Sensor
A carbon monoxide sensor detects dangerous levels of carbon monoxide…
Carbon Monoxide Testing
Carbon monoxide (CO) testing detects this colorless, odorless toxic gas…
Carbon Neutral
Carbon neutral refers to operating an HVAC system or facility…
Carbon Offset
A Carbon Offset is a tradable credit representing one metric…
Carnot COP
Carnot COP is the theoretical maximum coefficient of performance for…
Carnot Cycle
The Carnot Cycle is an idealized thermodynamic cycle consisting of…
Carpet Emissions
Carpet emissions include volatile organic compounds from fibers, backing materials,…
Carrier Equation
An empirical formula developed by Willis Carrier for calculating the…
Carrier HAP
Carrier HAP (Hourly Analysis Program) is Carrier Corporation’s proprietary building…
Cartridge Filter
Cartridge filters are cylindrical filter elements with pleated media that…
Cascade Control
A control strategy where the output of a primary (master)…
Cascade Refrigeration
Cascade refrigeration uses two or more separate refrigeration cycles operating…
Cascade Refrigeration System
A refrigeration arrangement using two separate refrigerant circuits at different…
Cassette Indoor Unit
A ceiling-recessed indoor unit that mounts flush with the ceiling…
Category I Appliance
A non-positive-pressure vented appliance with flue gases hot enough to…
Category IV Appliance
A positive-pressure flue gas venting classification for appliances with flue…
Cavitation
The formation and violent collapse of vapor bubbles inside a…
Cavity Insulation
Cavity insulation is thermal material installed within the hollow spaces…
CEE Qualified
CEE Qualified designation indicates that an HVAC product meets the…
CEE Tier
CEE Tier is a classification system developed by the Consortium…
CEER
CEER, or Combined Energy Efficiency Ratio, is a metric used…
Ceiling Access Panel
A ceiling access panel is a removable or hinged opening…
Ceiling Diffuser
A ceiling diffuser is a supply air terminal mounted flush…
Ceiling Fan
A ceiling fan is a mechanical ventilation device mounted to…
Ceiling Fan CFM
Ceiling fan CFM is the cubic feet per minute of…
Ceiling Fan Efficiency
Ceiling fan efficiency measures how effectively a fan converts electrical…
Ceiling Plenum
The concealed space between a suspended ceiling and the floor…
Cellulose Insulation
Cellulose insulation is a loose-fill or blown material composed primarily…