2,400+ Definitions
HVAC GLOSSARY
Every HVAC term, acronym, and industry phrase — defined in plain English.
Backflow Preventer
A backflow preventer is a critical safety device that allows…
BACnet
BACnet is an open-source communication protocol standard developed by ASHRAE…
BACnet Interface
A communication gateway or built-in capability that allows a VRF…
BACnet IP
A BACnet network variant that encapsulates BACnet messages within UDP/IP…
BACnet MSTP
The Master-Slave Token-Passing physical layer and data link protocol variant…
Bag Filter
Bag filters are cylindrical or rectangular fabric containers that capture…
Balance Point Temperature
The outdoor temperature at which a heat pump’s heating capacity…
Balanced Flue
A sealed combustion system in which both the air intake…
Balanced Mechanical Ventilation
Balanced mechanical ventilation simultaneously supplies filtered fresh air and exhausts…
Balanced Ventilation
Balanced ventilation systems simultaneously supply and exhaust equal volumes of…
Balancing Damper
A balancing damper is a manually adjustable blade device installed…
Ball Valve
A Ball Valve is a quarter-turn shutoff valve featuring a…
Ball Valve Plumbing
A ball valve is a quarter-turn shutoff valve with a…
Ball Valve Service Valve
A full-port quarter-turn valve installed on compressor suction and discharge…
Balometer
A balometer is a specialized airflow measurement device that combines…
Barometric Damper
A weighted, hinged flap installed in the flue pipe of…
Base Temperature Sensitivity
The change in annual degree-day totals resulting from a change…
Baseboard Heater
A baseboard heater is a self-contained heating unit installed along…
Batch Solar Heater
A batch solar heater is a passive solar system that…
Bathroom Exhaust Fan
A bathroom exhaust fan is a ventilation device that removes…
Battery Capacity
Battery capacity is the total amount of electrical energy a…
Battery Cycle Life
Battery cycle life is the number of complete charge and…
Bearing Fluting
Washboard-like grooves worn into motor bearing races caused by high-frequency…
Bearing Lubrication
Bearing lubrication is the maintenance process of applying appropriate oils…
Belt Alignment
Belt alignment is the process of ensuring drive belts run…
Belt Replacement
Belt replacement is the process of removing worn or damaged…
Belt Tension Gauge
A belt tension gauge is a precision instrument that measures…
Benzene
Benzene is a volatile organic compound commonly found in indoor…
Bi-Flow Filter Drier
A bi-flow filter drier is a refrigerant line component designed…
Bidirectional Meter
A bidirectional meter is a utility-grade device that measures electricity…
Bifacial Solar Panel
A bifacial solar panel captures sunlight from both front and…
BIM
BIM (Building Information Modeling) is a digital methodology that creates…
Bimetallic Overload Relay
A thermal overload protection device using bimetallic strips that bend…
Bin Method
An energy calculation technique that groups outdoor temperatures into bins…
Bioaerosol
Airborne particles of biological origin including bacteria, fungal spores, viruses,…
Bioeffluent
Bioeffluent consists of volatile organic compounds and other chemical substances…
Biological Contaminant
Biological contaminants include bacteria, viruses, mold spores, and allergens that…
Biosafety Cabinet
A biosafety cabinet is an enclosed, ventilated laboratory workspace designed…
Bipolar Ionization
Bipolar ionization releases positive and negative ions into the air…
BIPV
BIPV is an acronym for Building Integrated Photovoltaics, referring to…
Bivalent Alternate Operation
A dual-fuel system mode where the heat pump shuts off…
Bivalent Parallel Operation
A dual-fuel system mode where both the heat pump and…
Black Iron Pipe
Black iron pipe is a steel tubing without galvanized coating,…
Blast Chiller
A blast chiller is a commercial refrigeration unit that rapidly…
Blast Gate
A sliding flat-plate damper inserted into a duct that controls…
Block Load
Block load represents the total HVAC system capacity required to…
Blower Door
A calibrated fan system temporarily mounted in a building doorway…
Blower Door Machine
A blower door machine is a calibrated fan system that…