2,400+ Definitions

HVAC GLOSSARY

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

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ENERGY STAR Certified
ENERGY STAR Certified indicates that an HVAC or solar product…
ENERGY STAR Fan
An ENERGY STAR Fan is a ventilation or circulation fan…
ENERGY STAR Most Efficient
ENERGY STAR Most Efficient represents the highest tier of ENERGY…
ENERGY STAR Version
ENERGY STAR Version refers to the specific generation or iteration…
Energy Storage System
An energy storage system captures and stores electrical energy for…
Energy Use Intensity
Energy Use Intensity (EUI) measures the total annual energy consumption…
EnergyPlus
EnergyPlus is a free, open-source whole-building energy simulation engine developed…
Enthalpy
Enthalpy is the total heat content of a substance, representing…
Enthalpy Control
Enthalpy control is an economizer strategy that compares the total…
Enthalpy Wheel
An enthalpy wheel is a rotating heat and moisture exchange…
Entropy
Entropy is a measure of disorder or randomness in a…
EPA 410
EPA 410 refers to the refrigerant handling certification program established…
EPA 608
EPA 608 is the federal certification examination required for technicians…
EPA 608 Certification
EPA Section 608 Certification is the federal certification required by…
EPA 609
EPA 609 refers to Section 609 of the Clean Air…
EPA SNAP
EPA SNAP (Significant New Alternatives Policy) is the Environmental Protection…
Equal Friction Method
The equal friction method is a standardized ductwork design technique…
Equal Percentage Valve
An equal percentage valve is a characterized control valve where…
eQUEST
eQUEST is a graphical interface for DOE 2 that simplifies…
Equilibrium
Equilibrium represents a state where all thermodynamic properties remain unchanged…
Equipment Clearance
Equipment clearance refers to the minimum required space surrounding HVAC…
Equipment Health Monitoring
Equipment health monitoring continuously tracks the operational status and performance…
Equipment Installation
Equipment installation refers to the placement and connection of major…
Equipment Pad
An equipment pad is a concrete or structural foundation designed…
Equipment Room
An equipment room is an enclosed space designed to house…
Equipment Schedule
An Equipment Schedule is a comprehensive table listing all mechanical…
Equipment Selection
Equipment Selection is the process of specifying individual HVAC components…
Equipment Start Up
Equipment Start Up is the systematic process of initially energizing,…
Equipment Startup
Equipment startup is the controlled activation and verification of an…
Equivalent Length
Equivalent length is a method of expressing the pressure drop…
Equivalent Round Diameter
Equivalent Round Diameter (ERD) is a calculated measurement that converts…
ERV (Energy Recovery Ventilator)
An Energy Recovery Ventilator (ERV) provides controlled fresh air ventilation…
ESPI Standard
The Energy Services Provider Interface (ESPI) Standard is a data…
ETL Listed
ETL Listed indicates that equipment has been tested and certified…
EUI
EUI is the abbreviation for Energy Use Intensity, a key…
Evacuated Tube Collector
An evacuated tube collector uses rows of glass tubes with…
Evacuation
Evacuation is the process of removing air and moisture from…
Evaporation
Evaporation is the phase change process where liquid converts to…
Evaporative Condenser
An evaporative condenser combines refrigerant cooling with water evaporation to…
Evaporative Cooler
An evaporative cooler, also called a swamp cooler, reduces air…
Evaporator Coil
The evaporator coil is the indoor heat exchange component of…
Evaporator Coil Cleaning
Evaporator Coil Cleaning is the removal of dust, mold, and…
Exfiltration
Exfiltration is the uncontrolled leakage of conditioned indoor air escaping…
Exhaust Damper
An exhaust damper is a mechanical device installed within an…
Exhaust Fan
An exhaust fan is a mechanical ventilation device designed to…
Exhaust Hood
An exhaust hood is a ventilation system component that removes…
Exhaust Ventilation
Exhaust ventilation removes stale air, moisture, and contaminants from indoor…
Expansion Loop
An expansion loop is a U-shaped or S-shaped pipe section…