2,400+ Definitions
HVAC GLOSSARY
Every HVAC term, acronym, and industry phrase — defined in plain English.
Blower Door Test
A blower door test is a diagnostic procedure that measures…
Blower Motor
A blower motor is an electric motor that drives the…
Blower Wheel Cleaning
Blower wheel cleaning is the removal of dust, dirt, and…
Blue Roof
A blue roof is a water retention system installed on…
Bluetooth HVAC
Bluetooth HVAC control uses short-range wireless connectivity to pair thermostats…
Boiler
A boiler is a heating system that heats water (or…
Boiler Installation
Boiler installation involves mounting a heating unit that produces hot…
Boiler Protection Control
A control strategy or device that prevents cold return water…
Boiling Point
The boiling point is the temperature at which a liquid’s…
Bonding
Bonding is the electrical connection of metallic components and equipment…
Booster Compressor
A compressor dedicated to the low-temperature stage of a two-stage…
Boot
A transition fitting that connects a round or rectangular branch…
Borehole Thermal Resistance
The resistance to heat transfer between the circulating fluid in…
BPI Certification
BPI (Building Performance Institute) Certification validates professional competency in building…
Brake Horsepower
Brake horsepower (BHP) is the mechanical power required to operate…
Branch Circuit Controller
A refrigerant distribution device used in VRF systems that divides…
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…