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What Is the Difference Between HVAC and Furnace?

May 17, 2022

Most people use the terms HVAC and furnace interchangeably. While it is true that a furnace is often part of an HVAC system, there are some notable differences between these two pieces of equipment. Knowing the differences can help you make an informed decision when shopping for a heating and cooling system for your home or business. 

In a nutshell, a furnace heats your home. An HVAC system combines a furnace, air conditioner, and ventilation system (more on that below). So, if you need HVAC service, it may or may not include the furnace. Below, we look closely at the difference between HVAC and furnace.

What Is HVAC?

HVAC is an acronym that refers to three main components in a heating and cooling system.

  1. The furnace (heating)
  2. The Air conditioner (cooling)
  3. The ductwork and vents (ventilation)

All three systems work together to provide your preferred comfort level in relation to the temperature outside. 

Air Conditioner

During the summer, you turn on your air conditioner. The AC unit outside kicks on and converts warm air into cool air. It then distributes the air into the HVAC system, through the filter, and out the vents in each room in your house. 


During the summer, you turn your AC off and turn your furnace on. Fortunately, you use the same thermostat for the furnace as you do the AC. The furnace turns on when you switch the thermostat to ‘heat.’ The furnace uses an element to produce heat and distributes it through the vents in each room in your house. 


The third main component of your HVAC is the ventilation network or system. Ventilation starts with the filter. The air passes through the filter, collecting air particles and contaminants to keep the air clean. The air then passes through the ductwork and out the vents. 

There are four main types of HVAC systems for homes and businesses.

  1. Packaged heating and air systems
  2. Duct-free sytems
  3. Hybrid systems
  4. Split systems

The most common type of HVAC is a heating/cooling split system. The air conditioner is the outside unit. The furnace is the inside unit. Both distribute air into the same ductwork. 

If you’re wondering, the air conditioner unit is outside the home because its primary function is to remove heat from the air, and the heat needs somewhere to go. This method allows the AC to cool your home without simultaneously heating it. 

What Is a Furnace?

As we’ve stated before, the main difference between HVAC and a furnace is that a furnace has one primary function: producing and distributing heat, and the HVAC system includes the furnace. 

There are two main types of furnaces for split systems.

1. Gas Furnace

As the name implies, a gas furnace runs on natural gas. The furnace burner ignites the gas. The resulting flames heat the metal heat exchanger. The exhaust from the flame escape through a flue. The exchanger transfers the heat. The furnace blower distributes the hot air into the ductwork, where it escapes out the vents and into each room in the house.

2. Electric Furnace

Learning how an electric furnace works is easy if you’ve ever used a hairdryer. The furnace draws air into the HVAC system through an exchanger. A heating element warms the air. The furnace blower distributes the air into the ductwork and out the vents. So, the only real difference between a gas furnace and an electric furnace is the method for heating the air.

If the air conditioner unit is outside. Where is the furnace? In most cases, the furnace is located somewhere in your house – usually a central location. In some cases, the furnace may be in the garage, crawlspace, or basement. 

Most home designers try to position the furnace in the central part of the house for maximum efficiency. It allows the furnace to distribute the warm air evenly to each room. 

What is the Difference Between HVAC Service and Furnace Service?

There are times when HVAC service and furnace service overlap. However, working on one without working on the other is possible. 

HVAC Service

Since an HVAC service contains an air conditioner and ductwork, it’s possible to work on the system without touching the furnace. For instance, an HVAC company in Franklin, IN, may need to perform the following jobs separate from the furnace:

  • Change the air filter
  • Repair or replace the ductwork
  • Calibrate or replace the thermostat
  • Replace the wiring, fuses, or breakers

These are all services normally associated with HVAC repair. If there are major problems with the system, you may need an HVAC replacement, including replacing the air conditioner and the furnace.

Furnace Service

Just as HVAC service may not include the furnace, a furnace repair or replacement can occur independently of the rest of the system. As such, several problems can arise that are unique to the furnace.

  • Damaged or worn pilot light
  • Damaged or worn element
  • Cracked heat exchanger
  • Damaged blower or motor
  • Limit switch malfunction
  • Frayed blower belt

Since you only use your furnace during the winter, you will only notice them when you turn the furnace on. For this reason, you may want to schedule furnace maintenance before the winter starts. Doing so can help you catch small issues before they become costly.

Schedule HVAC Service and Repair in Franklin, Indiana

If your HVAC and furnace has problems, and you need an HVAC company right away, contact Johnson Comfort. We offer complete HVAC installation, repair, and maintenance in Franklin, Indiana. To schedule service, fill out the contact form or give us a call and get a free estimate.

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