What Is HVAC and How Does It Work?

hvac system installed in a house

We all know how uncomfortable it feels when it’s too hot or too cold in your home. That’s why having a good HVAC system is essential to staying cool and cozy throughout the year.

The basic concept of HVAC is simple, but the technology behind it can be complex. Put simply, an HVAC system is a network of machines and components that regulate your home’s temperature, air quality, and humidity.

What Is an HVAC System?

First of all, the acronym HVAC stands for “heating, ventilation, and air conditioning.” A typical HVAC system consists of several components, including: 

  • Furnace or heat pump 
  • Air conditioner 
  • Intake and exhaust ducts
  • Blowers
  • Filters
  • Thermostat
  • Fan

Each system component works together to control your home’s temperature, air quality, and humidity.

Different kinds of HVAC systems are available, such as split systems, which separate the outdoor unit from the indoor unit. Other types of HVAC systems include packaged units, ductless mini-splits, and geothermal systems. The type of system you choose should depend on the climate where you live and the size of your home.

Now let’s take a look at what HVAC systems are made of and how they work their magic.

How Does an HVAC System Work?

Though the operation of an HVAC system may vary depending on its type, at the heart of each system is a series of components that work together to regulate the flow of air and maintain comfortable temperatures.

Here is a breakdown of the main components of an HVAC system and how they work:

1. Thermostat – This is like the brain of the HVAC system. It reads the temperature in your home and sends a signal to the other components to adjust the temperature when needed.

2. Heat Exchanger – Heat exchangers facilitate heat transfer from one medium to another without mixing them up. For example, cool, clean air passes over the heat exchanger’s enclosed combustion chamber, which contains warm exhaust gasses.

3. Blower Fan – When the thermostat detects that the temperature inside is not at its set point, it triggers the HVAC blower motor to start up, which powers a fan that distributes hot or cold air produced by the heating/cooling system. This could include electric and gas furnaces, air conditioners, or heat pumps.

4. Condenser Coil – The condenser coil is vital to air conditioning, releasing heat outside the unit. It cools and converts refrigerant into liquid after it has been heated and pressurized in the compressor.

5. Evaporator Coil – The evaporator coil captures heat from the air, working with a condenser coil to keep your home cool.

6. Combustion Chamber – The combustion chamber burns the fuel source and warms the passing air. It’s the engine of your heating system.

HVAC Units

The components of an HVAC system are typically grouped into one or more units. Depending on your system type, these units can be installed inside and/or outside the home.

Heating System

heat pump outside a house
Photo Credit: onepony / Canva Pro / License

When the colder months hit, an HVAC system’s heating unit can really come in handy. It usually uses a furnace to heat up the air in your home and circulate it throughout. But there are other options available, such as boilers and heat pumps.

It depends on your home’s climate, size, and layout when deciding which type of heating system to choose.


A furnace works by heating up air that is then circulated throughout the home through ducts. The hot air flows into the home’s living spaces, providing warmth. A furnace can be powered by a variety of energy sources, including electricity, natural gas, oil, and propane.

Furnaces are usually the most cost-effective and efficient heating option, particularly if you live in a cold climate. Typically, a new furnace can cost between $2,383 and $6,110 in total, depending on the type and size.

In addition to providing warmth, a furnace can also help keep your home’s air clean through filtration. Newer models come with air filters that can trap dust, pollen, and other allergens, helping to reduce indoor air pollution.


A boiler is a type of heating system that uses hot water instead of air to provide warmth. Either electricity or natural gas powers boilers, and they work by heating up water in a tank before circulating it around your home via radiators and other components. 

Boilers are excellent for homes requiring multiple rooms to be heated at once or homes with multiple levels. 

Installation costs for boilers usually range from $3,500 to $8,500, depending on the size and type. 

Heat Pumps

Heat pumps are both a heating and cooling solution, and they work by moving heat from one place to another. They are usually powered by electricity and use a heat exchanger to transfer warmth indoors and outdoors.

Heat pumps are great for climates with milder winters, as they do not need to work as hard to provide warmth. Heat pumps also cost less to operate than other traditional heating systems, making them an ideal choice for those looking to save money on their energy bills.

The typical range of installation costs for heat pumps is between $4,000 and $8,000 in total.

Geothermal Heat Pumps

Geothermal systems are HVAC systems that use the ground or water as a heat source. They use underground piping to transfer heat from the ground to your home, providing both heating and cooling.

According to Energy.gov, geothermal systems require little to no maintenance and are highly efficient.

The downside is that installation costs for geothermal systems are significantly higher, ranging from $14,000 to $34,000, including materials and labor. However, the long-term savings make up for the initial investment.

Cooling System

Cooling System outside a house
Photo Credit: PublicDomainPictures

The most familiar part of an HVAC system is the air conditioning unit. This component functions to cool air and remove humidity from indoor spaces with the help of a refrigerant, compressor, and condenser.

AC units use refrigerant to absorb heat from inside a space before releasing it outside. The compressor pumps the refrigerant around the system, and the condenser expels the heat.

When selecting an air conditioning unit, a few key factors, such as size, type, and efficiency rating, must be considered. The unit size should be based on the square footage of the room or space that needs cooling, as well as other factors such as insulation and windows.

There are a few different types of air conditioning systems, including:

  • Window Units
  • Ductless Mini-Splits
  • Central Air Conditioner Systems

Window units are ideal for single rooms, while ductless mini-splits are great for zoned cooling. Central AC systems are the most cost-efficient and energy-efficient solution for larger homes. Generally, air conditioning units are powered by electricity.

On average, a new AC unit costs between $3,500 and $8,000, including installation.

Ventilation System

Having good ventilation is a must for indoor air quality. Vent systems in homes balance out air pressure and temperature, as well as circulate fresh air. Ventilating also helps keep away allergens, dust, and other polluting particles that cause health problems. 

There are either natural ventilation methods, such as windows and doors, or mechanical ventilation methods, like a whole-house fan. 

Duct System

HVAC ducts are responsible for transporting heated or cooled air throughout a home. The design and installation of the ducts are the keys to an efficient system. 

To ensure the best results, ducts should be tailored to fit the house layout, sized correctly, and properly sealed to avoid any energy loss. Poorly designed or installed ducts may result in wasted energy, leading to increased costs in the long run.

The cost of installing or replacing ductwork can be high, ranging from $2,000 to $5,000 in total, depending on the size of your home.

HVAC Control System

Most HVAC systems now come with thermostats and other control systems that let you manage the temperature in your home. You can program these to run at certain times of the day or even control them remotely with a mobile device so you can save on energy costs.

Common centralized control systems include Wi-Fi thermostats, zoning systems, and energy management systems. These systems help you cut energy consumption and save on your energy bills.

 A new thermostat usually costs between $120 and $330, including installation.

Type of HVAC System

It may seem like you’d need just one component to keep your house within the perfect temperature range, but there are actually four types of HVAC systems you should know about. 

Split System

A split system has a unit for cooling and another for heating, but these components are all located in different places, so the name “split” comes from the two-part setup. Split systems are the most cost-effective option and work well in smaller houses.

Split systems have two main components: one outdoors, containing the compressor and condenser coils, and an indoor unit which usually houses a furnace or air handler. 

Packaged System

A packaged system is the perfect HVAC solution for homeowners in mild climates. It’s compact and cost-effective, making it an ideal choice for many households. Plus, it’s got the convenience of all components being housed within one unit outside the home.

It includes a compressor, condenser coils, and air handler, all combined in one space-saving unit. Setting up this type of system is much simpler than with split systems because it’s only one piece of equipment. Plus, a packaged system is an excellent solution in areas with little or no space inside the house for an HVAC.

Hybrid System

Hybrid systems are a perfect choice for homes in climates that experience both cold and hot weather. Combining both split and packaged elements, they offer the comfort of cooling with heating convenience. The dual indoor unit houses a furnace and evaporator coils that switch between gas and electric energy for maximum efficiency. 

Ductless Mini-Split System

Ductless systems are a great way to heat and cool your home effectively. With an individual air handler in each room, you can easily control the temperature of each space separately.

Plus, they require no costly or extensive ductwork installation like other HVAC systems. Not only are they economical, but they’re also energy-efficient. So, you can cool down one area whenever you want without wasting energy across the whole house.

However, the ductless mini-split’s price tag is usually higher than that of other HVAC systems, typically ranging from $3,000 to $9,500 for installation.

Professional HVAC Services

Photo Credit: ronstik / Canva Pro / License

No matter which type of HVAC system you have, some professional services are necessary to keep it running smoothly. These may include regular inspections, repairs, and filter replacements.

HVAC Installation

It’s essential to get a qualified pro for the job when installing or replacing an HVAC system. The HVAC installation usually includes choosing or measuring an appropriate system, getting materials and HVAC equipment, doing the installation work on-site, and testing and setting up the system when it’s finished.

The average cost of a new HVAC system installation is around $5,000 to $9,000.

HVAC Repair

HVAC repair means finding out why something isn’t working right and then fixing it. Sometimes, it involves replacing the broken parts, but that isn’t always needed. HVAC technicians use special tools and testing equipment to uncover the problem and repair or change out any faulty components. Generally, they’ll come to you and take care of the repair right on the spot.

Depending on the job’s complexity, HVAC system repair costs from $180 to $580 and can take a few hours to several days to complete. 

HVAC Maintenance

HVAC maintenance is the process of inspecting, cleaning, and tuning up an existing HVAC system to ensure it runs safely, efficiently, and reliably. This type of service usually involves inspecting and cleaning the system, lubricating moving parts, and testing for proper operation.

Most HVAC systems require a yearly tune-up, and bi-yearly inspections are ideal for energy efficiency. Plus, these little tweaks can extend the life of your unit, which can last up to 25 years with good maintenance habits. Plus, regular HVAC maintenance costs far less than an emergency repair.

Those biannual HVAC inspections cost around $250 to $450.

FAQ About HVAC Systems

What is the difference between AC and HVAC?

AC stands for air conditioning, a system that cools and dehumidifies air in a room or building. HVAC stands for heating, ventilation, and air conditioning, which is an all-encompassing system that not only cools but also warms and circulates the air in a space. In short, AC is just part of the HVAC system.

Where are HVAC systems used?

HVAC systems are used in residential, industrial, and commercial buildings to provide comfortable indoor climates.

How often should I get my HVAC system serviced?

It is a good idea to get your HVAC system checked out every year to make sure everything is running smoothly. This way, you can catch problems early before they become too big of an issue and save yourself time and money in the long run.

Final Thoughts

HVAC systems are an invaluable asset for any home, as they improve the overall level of comfort while keeping energy costs low. The acronym stands for Heating, Ventilation, and Air Conditioning, and these three mechanics sections work together to ensure a comfortable atmosphere.

HVAC provides an essential service, from regulating the room temperature to keeping units clean and running smoothly. Knowing which type best suits your home and climate can be difficult due to the many options available. The best way to find the perfect unit for your home is to consult a professional HVAC technician. With their advice, you’ll be sure to find a system that works for your space and budget.

Main Image Credit: CRobertson / Canva Pro / License

Luminita Toma

Luminita Toma is a nature-loving writer who simply adores anything pretty, from colorful flower gardens to chic interior design. After plenty of research on landscaping and home improvement, she’s got a keen eye for what makes a home beautiful. When she’s not sharing what she’s learned, there’s nothing she enjoys more than chilling with her friends, hitting the theatre, or traveling.