Glossary of Terms

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Glossary of Terms

Heating Venting and Air Conditioning(HVAC)

Image Term : Definition
Daikin Heat Pump HP Right Quarter

Air Conditioner

Device used to lower air temperature. Cooling typically happens through heat transfer with refrigerant cycle.
Daikin Air Handler G ARUF Daikin RtQtr Case LR

Air Handler/Electric Furnace

Metal box containing blower, heating elements and system controls. Normally attached to duct work which distributes conditioned air throughout a building.

BTU (British Thermal Unit)

Measurement of energy(heat) required to raise a temperature. In the U.S., BTU is used for the rating power of HVAC systems.
Daikin Coil CAPF RightQuarter WithBadge Case LR


Equipment that performs a heat transfer as air blows over the unit.
damper sleeve


An adjustable blade inside duct to control air flow.
Honeywell Dehumidifier


Equipment used to extract and remove humidity from air. Drops air temperature to turn water vapor to liquid. Dehumidification naturally occurs during air conditioning.
Flex Duct


Method of transferring air from one area to another. Used in heating, cooling or ventilation.

Fresh Air

Outside air that is introduced inside a building to help cycle new air.


Removable device that is placed in the air intake portion of the system. It provides protection for the motor, fan, and heating coil by removing impurities. It also contributes to the Indoor Air Quality of a building.
Daikin Gas Furnace GF Top Right


Similar to an air handler. Metal box containing burners, heat exchanger, blower and controls. Fuel can be Natural Gas, Propane, or Oil.
Grille for home hvac system


A covering over a duct opening that has slots in it to deliver(supply) or recover(return) air. The grille directs air and prevents entry of larger objects.
Heat Exchanger

Heat Exchanger

Portion of a combustible furnace(Gas or Oil) that transfers heat to be expelled by the unit.
Daikin Heat Pump HP Right Quarter

Heat Pump

Outdoor unit that has a compressor to cycle hot and cold refrigerant. Transfers heat from one area to a cooler area.


Heating Seasonal Performance Factor. Used to measure the heating efficiency of air source heat pumps. Higher the number, the more efficient the unit.

Indoor Air Quality (IAQ)

Term used to refer to air quality inside a building or structure. It commonly relates to the health and comforts of the occupants inside the building.
Daikin Package Unit

Packaged Unit

An air handler specially designed for outdoor installation with ducts that run into a structure. They normally contain both the heating and cooling portions of the system.
Custom Plenum Chamber


Metal boxes attached to an indoor system. Airflow is then distributed from the plenum into ductwork.
refrigerant 410 A


A mixture that changes from a liquid to gas to transfer heat from one place to another.


Seasonal Energy Efficiency Ratio. Cooling performance rating system for Air Conditioners and Heat Pumps. Higher the rating, the more efficient the system.
Daikin HVAC Heating and Cooling Product Group

Split System

Combination of an outdoor unit and an indoor unit. Most common type of system.


General term referring to a unit that performs a specific HVAC function.
Honeywell Pro


Monitor and regulator of a heating and cooling system. Used to set a desired temperature.

Thermostatic Expansion Valve(TXV or TEV)

A piece of equipment that meters the flow of liquid refrigerant entering an evaporator while measuring the vapor refrigerant leaving the evaporator.


System designed to operate on a high and low setting during different demands placed upon the system.
HVAC Zoning System


Created section of a building or space that are controlled independently of each other. Different sections then can have own desired temperature using independent thermostats.