(602) 842-0009

All Articles

HVAC Glossary of Terms to Know

Closeup of the top of an AC unit.

Heating, Ventilation, and Air Conditioning (HVAC) systems play a pivotal role in maintaining comfortable indoor environments. However, understanding the various HVAC terms and definitions can be a bit overwhelming for someone not well-versed in the field. To help demystify this complex world, we've compiled a comprehensive HVAC glossary of terms you should know.

Whether you're a homeowner or a building manager, this glossary will help you communicate effectively with HVAC professionals, make wise choices for your system, and maintain a comfortable and energy-efficient indoor environment.

Let’s get into it!

Trust George Brazil for Expert HVAC Repairs, Installations, and Maintenance.

Whether you need a quick AC repair, a new heating system, or trustworthy advice about the best air quality products, turn to George Brazil for guaranteed satisfaction. We’ve been trusted by homeowners and businesses across the Phoenix area since our founding in 1955, and we’ve earned more than 2,000 5-star reviews. Call us today for fast scheduling, honest prices, and good old-fashioned service that leaves you glad you contacted us!

Glossary of HVAC Terms

Air Handler

An air handler is a vital part of the HVAC system responsible for circulating conditioned air throughout a building. It typically includes a blower, heating or cooling elements, filter racks or chambers, and sound attenuators.

Air Ducts

Air ducts are channels or passages used to distribute heated or cooled air throughout a building. They are essential for maintaining proper airflow.

BTU (British Thermal Unit)

BTU is a unit of measurement used to quantify the amount of energy required to raise the temperature of one pound of water by one degree Fahrenheit. In HVAC, BTUs are used to measure heating and cooling capacity.


The blower is a component of the air handler that is responsible for moving air through the system. It can be a fan or other air-moving device.


A boiler is an appliance used to heat water or other fluids, which is then distributed throughout the building to provide warmth. It's a common component in hydronic heating systems.


The compressor is the heart of an air conditioning system. It compresses refrigerant gas to increase its temperature, which is essential for cooling.

Condenser Coil

The condenser coil is a heat-exchange component that releases heat absorbed from the indoor air into the outdoor air. It plays a crucial role in the cooling process.

HVAC Condensate Drain

The condensate drain is a plumbing component that collects and removes condensation produced during the cooling process. It prevents water damage and mold growth.

Cooling Load

The cooling load is a measure of the heat that needs to be removed from a space to maintain a comfortable temperature. It depends on factors like insulation, occupancy, and outdoor temperature.


Dampers are valves used to control or regulate the flow of air in HVAC systems. They are often used to direct airflow to specific zones or rooms.


Ductwork is a system of pipes or channels that distribute air throughout a building. It is essential for both heating and cooling.

Evaporator Coil

The evaporator coil is another heat-exchange component in an HVAC system. It absorbs heat from the indoor air and cools it down by evaporating refrigerant.


Filtration is the process of removing particles and contaminants from the air. HVAC systems use filters to improve indoor air quality by trapping dust, allergens, and pollutants.

Heat Exchanger

A heat exchanger is a component that transfers heat between two fluids without them coming into direct contact. In furnaces, for example, it separates combustion gasses from the air that circulates through the building.


A humidifier is a device used to add moisture to the indoor air. It is especially valuable in dry climates or during the winter when indoor air can become too dry.

IAQ (Indoor Air Quality)

Indoor air quality refers to the quality of the air within a building. Good IAQ ensures that the air is free from pollutants and allergens, providing a healthy and comfortable environment.

Load Calculation

Load calculation is the process of determining the heating and cooling requirements of a building. It considers factors such as insulation, occupancy, and climate to size the HVAC system appropriately.

Mini-Split System

A mini-split system is a type of ductless HVAC system that consists of an outdoor compressor unit and one or more indoor air-handling units. It provides zoned heating and cooling without ductwork.


Refrigerant is the substance used in HVAC systems to transfer heat between the indoor and outdoor units. Common refrigerants include R-410A and R-22, though newer, more environmentally friendly options are becoming popular.

SEER (Seasonal Energy Efficiency Ratio)

SEER is a rating that measures the energy efficiency of air conditioning units. The higher the SEER rating, the more energy-efficient the system is.


A thermostat is a control device that allows users to set and adjust the desired temperature in a building. Modern thermostats can be programmable, smart, or manual.


Ventilation refers to the process of bringing fresh outdoor air into a building while exhausting stale indoor air. It is crucial for maintaining good indoor air quality.

VRF (Variable Refrigerant Flow)

VRF is a type of HVAC technology that enables precise control over the amount of refrigerant flow to different indoor units. It's known for its energy efficiency and ability to maintain consistent comfort in different zones.


Zoning is the practice of dividing a building into different heating and cooling zones. It allows for greater control over temperature and can lead to energy savings.

Enjoy the Highest Quality Service On Your Next HVAC Repair, Tune-Up, or Installation.

Since 1955, George Brazil has proudly served Phoenix-Metro homeowners with 5-star service. In fact, we have more than 2,000 5-star reviews and a Torch Award for Ethics to prove it. From AC tune-ups and high-efficiency heat pump installations to duct sealing and more, our expert technicians are here to help you enjoy better comfort, lower energy bills, and longer-lasting equipment. Call us at (602) 842-0009 or schedule online below.

Related Articles