2,400+ Definitions

HVAC GLOSSARY

Every HVAC term, acronym, and industry phrase — defined in plain English.

All A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Grains of Moisture
Grains of moisture measure the absolute humidity content in air,…
Gravity Damper
A gravity damper is a passive, motorless damper that uses…
Grease Duct
A grease duct is the ductwork component of a kitchen…
Grease Filter
A grease filter is a mechanical component installed in Type…
Green Button Data
Green Button Data is a standardized format for downloading energy…
Green Globes
Green Globes is a web-based building environmental design and management…
Green Mortgage
A green mortgage is a specialized home loan that recognizes…
Green Power Purchase
A Green Power Purchase is the acquisition of electricity from…
Green Roof
A green roof is a vegetated roofing system where living…
Grid Defection
Grid defection occurs when customers disconnect from the utility grid…
Grid Frequency
Grid frequency is the rate at which alternating current (AC)…
Grid Interactive
Grid-interactive HVAC systems communicate with the electricity grid to optimize…
Grid Interactive HVAC
Grid Interactive HVAC systems are smart heating and cooling units…
Grid Stability
Grid stability refers to the electrical grid’s ability to maintain…
Grid Tie Inverter
A grid tie inverter converts DC power from solar panels…
Grid Tied System
A grid-tied solar system connects directly to the utility grid…
Grid Voltage
Grid voltage is the electrical potential difference maintained throughout the…
Grille Neck
The duct connection opening at the back of a return…
Ground Fault Circuit Interrupter
A Ground Fault Circuit Interrupter (GFCI) is a specialized electrical…
Ground Fault Protection
A protective function that detects current flowing to ground through…
Ground Heat Exchanger
The buried or submerged piping circuit in a geothermal system…
Ground Mount Solar
Ground mount solar systems position photovoltaic panels on metal or…
Ground Source Heat Pump
A Ground Source Heat Pump (GSHP), also known as a…
Ground Wire
The ground wire provides a safety path for electrical current…
Ground-Coupled Heat Pump
A heat pump system that exchanges heat with the earth…
GW
A gigawatt (GW) equals one billion watts or 1,000 megawatts,…
GWP
Global Warming Potential is a measure of how much heat…
GWP (global warming potential)
A relative measure of how much heat a refrigerant traps…
GWP 150
GWP 150 refers to refrigerants with a Global Warming Potential…
GWP 700
GWP 700 represents refrigerants with a Global Warming Potential of…
GWP 750
GWP 750 is a regulatory threshold that limits refrigerant global…
Halide Torch
A halide torch is a flame-based leak detection tool that…
Hard Start
A hard start kit is an electrical device that provides…
Hard Start Kit
A hard start kit is a capacitor assembly that provides…
Harmonic Distortion
Harmonic distortion is the presence of electrical frequencies at multiples…
Harvest Cycle
In ice machine terminology, the phase in which the formed…
Hazen Williams
The Hazen-Williams equation is an empirical formula used to calculate…
HCFC Refrigerant
HCFC refrigerants (hydrochlorofluorocarbons) are transitional compounds containing hydrogen, chlorine, fluorine,…
Header Trench
The shallow trench that runs from a building to the…
Heat
Heat is the transfer of thermal energy between systems, objects,…
Heat Anticipator
A heat anticipator is a small, adjustable resistive device located…
Heat Capacity
Heat capacity is the amount of thermal energy required to…
Heat Engine
A heat engine is a device that converts thermal energy…
Heat Exchanger
The heat exchanger in a gas furnace is the component…
Heat Exchanger Inspection
A heat exchanger inspection examines the furnace or air handler…
Heat Flux
Heat flux is the rate of heat energy transfer per…
Heat Gain vs. Cooling Load Distinction
The conceptual separation between the rate at which heat enters…
Heat Load
Heat load (also called heating load or heat loss) is…