Some HVAC Terms and Their Definitions

The HVAC industry has its own terminologies and for you to understand them, here are some of the frequently used technical terms and their meanings.

Air Handling Unit (AHU): this is a large metallic box with a cooling coil and/or heating element and some other components. It is used to control and move air as part of an HVAC system.

Air Cleaning: this is a part of an indoor unit. It controls air quality by filtering off harmful contaminants such as debris and dirt.

ACCA: this acronym stands for Air Conditioning Contractors of America, an association saddled with the responsibility of representing HVAC contractors.

AFUE Rating: AFUE means Annualised Fuel Utilisation Efficiency. It is unitless and expressed in percentage. It is the measure of the efficiency of heating units especially furnaces. The higher the AFUE rating, the higher the equipment’s efficiency.

Ambient Temperature: this is the temperature of air surrounding the cooling or heating system.

Air Balancing: this is the process of tuning an AC unit until the desired cooling or heating effect is efficiently achieved.

Blower: this is contained in the AHU. It is used to induce the flow of air.

BTU: the acronyms means British Thermal Unit. It is used to relate the cooling and/or heating capacity of a device.

Capacity: this is often displayed in units of BTU/h on nameplates of equipment. It refers to the capability of an HVAC system to cool or raise the temperature of a given space. A high capacity value denotes that a unit will supply more cooling or heating power.

Compressor: this is often described as the heart of a heat pump or AC. It is responsible for the pressurisation and movement of refrigerant through an HVAC system. it prepares the refrigerant for heat exchange in the condensing coil.

Coil: A cooling or heating element produced from tubing, fins or pipes.

Condensing Coil: contained in the outdoor unit of a central cooling system (CCS). It facilitates heat transfer from the refrigerant.

Condenser: this device removes heat from a refrigeration system and moves it to a unit that transfers it to a sink.

CFM: this is a measure of the amount of airflow in an HVAC system

Damper: this is a moveable plate or valve utilised in ductwork to regulate airflow.

Dehumidifier: this device strips air of excess moisture

Ducts: ducts are conduits that serve as medium for air movement and distribution in HVAC systems.

EER: Energy Efficiency Ratio – it is a measure of cooling efficiency

ERV: ERV means Energy Recovery Ventilator. This equipment moves fresh air into a given space and draws out stale air.

Filter: used to remove contaminants from air to ensure that quality air is distributed and the HVAC equipment is protected.

R-22: used as refrigerants in heat pumps and ACs but has been discontinued because of its ozone layer depleting ability.

R-410A: this refrigerant has replaced R-22. It does not contain hazardous substances

Refrigerant: A fluids that facilitates heat transfer into or out of the air distributed in a given space.

Thermostat: monitors and regulates the temperature in a given space.


For more HVAC related terms, lookup HVAC Glossary.