2,400+ Definitions
HVAC GLOSSARY
Every HVAC term, acronym, and industry phrase — defined in plain English.
Branch Takeoff
A fitting that diverts a portion of airflow from a…
Brazed Plate Heat Exchanger
A brazed plate heat exchanger uses copper brazing to permanently…
Brazing
Brazing is a metal-joining technique using a filler metal with…
Brazing Flux
A chemical compound applied to dissimilar metal or non-copper joints…
Breadbox Solar Heater
A breadbox solar heater is a simplified passive water heating…
Breathing Zone
The breathing zone is the specific volume of air immediately…
Breathing Zone Outdoor Airflow
The minimum rate of outdoor air that must reach the…
BREEAM
BREEAM, or the Building Research Establishment Environmental Assessment Method, is…
Brine Cooling System
A secondary refrigeration arrangement where a salt solution or calcium…
Brine System
A brine system uses a salt-water or glycol solution as…
BS Box
A branch selector box used in heat recovery VRF systems…
BTU
A BTU (British Thermal Unit) is the standard unit of…
bubble point
The temperature at which the first bubble of vapor forms…
Bubble Solution Leak Check
Application of a soap-based or purpose-formulated liquid to joints and…
Buck-Boost Transformer
A small autotransformer used to raise or lower line voltage…
Buckling
Inward or outward deformation of duct walls caused by pressure…
Buffer Tank
A Buffer Tank is a large volume water storage vessel…
Building Automation System
A Building Automation System (BAS) is an integrated network of…
Building Electrification
Building electrification is the process of replacing fossil fuel-based heating,…
Building Energy Model
A Building Energy Model (BEM) is a detailed computational simulation…
Building Envelope
The building envelope is the complete physical boundary separating conditioned…
Building Integrated Photovoltaics
Building Integrated Photovoltaics (BIPV) are solar energy systems seamlessly incorporated…
Building Load Profile
A building load profile represents the hourly or time-interval energy…
Building Management System
A Building Management System (BMS) is an advanced software platform…
Building Material Emissions
Building material emissions are the release of chemical compounds from…
Building Science
Building science is the systematic study of how buildings function…
Bulk Sampling
Bulk sampling involves collecting actual contaminated building materials for laboratory…
Butterfly Valve
A Butterfly Valve is a quarter-turn shutoff valve with a…
Bypass Damper
A bypass damper is an automatic control damper that diverts…
Bypass Factor
The fraction of air passing through a cooling coil that…
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…