2,400+ Definitions
HVAC GLOSSARY
Every HVAC term, acronym, and industry phrase — defined in plain English.
Hydronic Balance Report
A Hydronic Balance Report documents water flow rates, pressure differentials,…
Hydronic Heating
Hydronic heating is a system that distributes heat through water…
Hydronic System
A hydronic system is an HVAC system that uses a…
Hyper Heat
A manufacturer marketing term, originating with Mitsubishi Electric, describing heat…
IAQ Dashboard
An IAQ dashboard is a centralized display or software interface…
IAQ Procedure
The IAQ Procedure is a performance-based ASHRAE 62.1 compliance method…
IBC
IBC stands for International Building Code, a comprehensive model building…
Ice Machine
An ice machine is a commercial refrigeration appliance that automatically…
IECC
Definition The International Energy Conservation Code (IECC) is a model…
IECC 2015
The 2015 International Energy Conservation Code updated energy efficiency requirements…
IECC 2018
The 2018 International Energy Conservation Code (IECC) establishes minimum energy…
IECC 2021
IECC 2021 is the 2021 edition of the International Energy…
IEER
IEER (Integrated Energy Efficiency Ratio) measures air conditioning system efficiency…
IGBT
An Insulated Gate Bipolar Transistor is the high-speed switching device…
Igniter
An igniter is an electrically heated ceramic element that reaches…
Ignition Control Module
An ignition control module is an advanced electronic component that…
IMC
The IMC is the International Mechanical Code, a model building…
Immersion Cooling
Immersion Cooling submerges entire servers or individual components in thermally…
In Duct Air Purifier
An in duct air purifier is an air treatment device…
In Row Cooling
In Row Cooling refers to cooling units positioned directly between…
Inches Water Column
Inches Water Column (IWC) is a unit of pressure measurement…
Inclined Manometer
An inclined manometer is a pressure measurement device with a…
Index Circuit
The duct path from the air handler to the terminal…
Indirect Circulation System
An indirect circulation system pumps heat transfer fluid (typically antifreeze…
Indirect Evaporative Cooling
A two-stage process where water evaporates into a secondary airstream…
Indirect Fired Chiller
An indirect fired chiller uses a separate heat source, such…
Indirect Water Heater
An indirect water heater uses heat from a boiler’s heating…
Indoor Air Quality (IAQ)
Indoor Air Quality (IAQ) refers to the air quality within…
Induced Draft
Induced draft is a ventilation method where a fan or…
Induced Draft Cooling Tower
An induced draft cooling tower uses a fan mounted at…
Induction Diffuser
A supply air diffuser designed so that the high-velocity primary…
Induction Unit
An induction unit is a type of terminal device used…
Industrial Heating
Industrial heating encompasses heating systems and equipment designed to warm…
Industrial Ventilation
Industrial ventilation systems remove contaminants, heat, humidity, and harmful substances…
Inertia Base
An inertia base is a massive concrete or steel platform…
Infiltration
The uncontrolled and unintended movement of outdoor air into a…
Infiltration Degree Days
A variant of the degree-day concept that weights temperature difference…
Infiltration Pressure Coefficient
A dimensionless factor relating wind-induced surface pressure on a building…
Infiltration Rate
Infiltration rate measures the volume of uncontrolled outside air entering…
Inflation Reduction Act
The Inflation Reduction Act (IRA), enacted in August 2022, represents…
Infrared Heater
An infrared heater is an industrial heating device that produces…
Infrared Inspection
Infrared inspection identifies equipment problems and energy losses by measuring…
Infrared Refrigerant Leak Detector
A leak detection instrument that uses an infrared light source…
Infrared Thermometer
An infrared thermometer measures surface temperature by detecting thermal radiation…
Inhibited Glycol
A heat transfer fluid consisting of ethylene or propylene glycol…
Inlet Guide Vanes
Adjustable vanes positioned at the inlet of a centrifugal compressor…
Input Line Reactor
An inductor placed on the AC input of a VFD…
Input-Output Module
A field device that extends the physical input and output…