Common HVAC Terms Explained

HVAC Terms You Should Know

Heating and cooling systems come with many different components and parts, and when you have an issue, knowing different terms can come in handy. Taking time to understand your HVAC system will help you navigate problems related to other things connected to your unit like ductwork, air filters, and more.

Here are some terms you should make yourself familiar with to stay ahead of problems with your system.

AC - Air Conditioner

A common term that most people are familiar with is AC, which stands for air conditioner. An air conditioner is an appliance or system that is designed to draw heat from a room or building.

There are two types of ACs that can be installed, which is the older window unit, and a more modern one that’s connected to the HVAC and ductwork. Modern models of an air conditioner are connected to central air conditioning fans and ducts that are able to cool the air in your home.

ACH - Air Changes Per Hour

ACH references the number of times per hour a room has air supplied or removed through natural and mechanical ventilation.

AFUE - Annual Fuel Efficiency Ratio

AFUE measures the energy efficiency of your furnace or boiler by dividing the ratio of the heat output by heat input.

Airflow Volume

Airflow volume is the amount of air circulated in a room or space and is measured in cubic feet per minute.


Air Handler

The air handler is the indoor part of the air conditioning system. This includes the fan and evaporator used in the summer and the condenser coil used in the winter.

BTU - British Thermal Unit

The BTU is a measurement of energy that is used to indicate the rate of cooling, dehumidifying, or heating your HVAC system.


A boiler’s job is to boil enough water to provide heating for a home. Pipes carry the steam and hot water created throughout the house, keeping it warm.


The condenser is a portion of a split HVAC system that is located outdoors. A condenser either removes or collects heat depending on the season. It also operates through coils that condense refrigerant vapor into a liquid that can be recirculated into the system.

Ductless Mini-Split

A ductless mini-split is a cooling system that contains indoor and outdoor components. They do not involve the ductwork in your home, and a house can have multiple single-zone systems that are all cooled by an air handler and condenser.


Ductwork is the system of ducts that work to distribute air from your HVAC system throughout your house.

Evaporator Coil

An evaporator coil operates within a furnace or air handler and moves cold refrigerant that removes heat from the air circulating throughout your home.


The furnace moves hot air throughout the house to provide warmth and uses the same ductwork as the central air system.

Heat Pump

A heat pump is a compressor that cycles hot and cold air. It moves energy in the opposite direction of heat flow by absorbing heat from a cold space. Afterward, it releases heat to a warmer space.


The acronym for heating, ventilation, and air conditioning.

HVAC Services With Griffin Mechanical, LLC

Our knowledgeable experts at Griffin Mechanical, LLC can help you navigate your heating and cooling system. We provide services like heating and cooling maintenance, ductwork, installations, and more. Give us a call at (615) 502-3030 if you have any questions and would like to schedule an appointment!