How the HVAC System Works

HVAC which stands for Heating, Ventilating or Ventilation and Air Conditioning is the technology of indoor and also for vehicular scope has the goal to provide thermal comfort and indoor air quality.
It makes use of different principles ranging from mechanical engineering, thermodynamics, heat transfer and fluid mechanics and has been an important and integral part of residential and commercial establishments where safe and healthy building or structure conditions are regulated in accordance to temperature and humidity using fresh and regulated air.
Different HVAC units do their role in integrating and utilizing the three central functions of the system which includes heating, ventilating and air conditioning. It also includes certain means of air delivery and removal from specific spaces and reduction of air infiltration and maintains pressure relationships between spaces.
Know that we already know that controlling the temperature of air as well as the humidity in homes and buildings plus maintaining high air quality are the basic functions of the HVAC system but how HVAC works?

Below are several types of systems we would look at to determine how exactly the HVAC system works:

Split Air conditioning system

Let’s identify as to why it is called a Split air conditioning system. Since the unit includes components located inside and outside of the home, it is literally split into two components. Some terms associate it with Central air conditioning.
An outdoor unit comprised of the condenser and compressor, and an indoor unit with a fan and an evaporator coil, typically, a split air conditioning functions to remove the warm air from inside a home or structure and cycling it back as cooler or lower temperature air through a system of supply and return ducts or passageways.
The compressor pumps powered by electricity pumps refrigerant through the system to collect heat and moisture from the inside space. The heat and moisture is then carried away from the inside and is blown over the cooled indoor coil which cools the air. The heat collected in the coil is then pumped and distributed outside of the home while the cooler air cycles back inside.
This is particular in warmer climates and is very effective in doing its role. Some units feature a lower indoor noise level compared to free standing air conditioning units. It also ensures quality air as the air returns drawn out of rooms and filtered through an air filtrating mechanism. This removes airborne particles and the output would be cleaner and filtered air distributed to homes.

Mini-Split/Ductless system

Unlike traditional split HVAC systems that a HVAC technician installs, the ductless system does not rely and utilize ducts to carry and route air throughout the home. It is designed to heat or cool a single room. Space, zone or an addition to your house that may lack or cannot accommodate any ductwork.
A mini-split/ductless system is powered by electricity and comprised of a relatively small outdoor condensing unit and a compact indoor evaporator unit, which hangs on the wall to control and direct airflow. The mini in this type of HVAC system’s name is a direct reference to the indoor unit’s diminutive size and inconspicuous appearance. The indoor and outdoor components are connected via copper refrigerant tubing and electrical wiring, requiring an opening just three inches or less in diameter.
As per HVAC trainings and studies, these types of system are recognized as energy efficient and extremely popular in the United States.


Misconceptions on furnace include the thinking that these are old technologies from the early 20th century which features a large gravity fed structure. However, in modern times, this presents a large contribution in indoor comfort all year round. Linking it with the mini split system as its counterpart, it does a great job in keeping the home or office warm during winter. The furnace fan or blower is also used to assist air conditioning system in circulating cooled air during warmer seasons.
From a gas furnace, heat is produced as an outcome of the combustion of natural gas in its burner. The heat is then distributed as the air passes from a heat exchanger blown and passes through certain ducts of the home.

Heat Pump or Air handler

A heat transporter which extracts warm air from your home during summer and then in turn reversing the operation to bring warm air during the winter.
HVAC explained through this system involves A heat pump is installed outside the home, similar to a central air conditioning unit the unit’s compressor circulating the refrigerant between it and the indoor air handler in turn absorbing or releasing heat en route, depending on the season. Unlike the furnace, it does not burn fuel to produce heat rather; it just uses electricity to move heat into or out of your home.


This technology ranges from the very basic and functional to the extremely sophisticated and feature rich ones.
In general terms, the thermostat controls the operation of the entire HVAC system and provides precise temperature regulation which has been an integral concept in HVAC training for contractors and service providers.
Newer digital, programmable thermostats such as ComfortNet™ Controlling Unit, feature both comfort- and efficiency-enhancing functionality. Programmable thermostats may be set to optimally regulate the temperature in any given spaces based on your preferred schedules and routine.

The central air conditioning system is a structure or system established wherein a centralized unit cools down or dehumidifies air before distributing this throughout a house or building.
The central air conditioning is different from the framework that relies on individual units in rooms or specified spaces of a given structure.
The system is often fused with a heating system as both systems get similar amounts of electricity and banks on duct works to dispersed cooled or heated air. With the scope of the system itself, this is commonly being used in large structures or in homes with extremely hot or humid climates.
With the system in place, the main unit is often situated in non-traffic or isolated areas or spaces outdoors which could either be an attic or a garage to isolate the amount of noise it generates upon refrigeration cycle which is the process that cools air and help in extracting humidity.
Fixing central air conditioner entails a certain degree of effort, skills and precision to ensure that the ultimate goal of the said system is met.
Let’s dig deeper on the question of how does a central air conditioning system work?
A central air conditioner has a primary part such as the air handler or furnace located in a separate area.
The unit then pumps cooled air throughout a given space such as a house or office set up through series of ducts and channels which is the same flow with that of the system utilized by forced air furnace during the heating season.
At this point, a thermostat comes into the picture.
How does central air thermostat work?
Generally speaking, a thermostat controls the operation of the central air conditioning unit and provides precised and accurate temperature regulation. It turns the cooling system on or off as the temperature rises or falls depending upon the preferred or set temperature by the owner and maintenance of the house or office.
A central AC regardless of the central air conditioner prices runs on electricity and removes heat from air through the principle of refrigeration. When the thermostat sends a signal to the main unit to lower the temperature, the cycle begins all over again. Refrigeration, obviously has a coolant or a refrigerant such as Freon that circulates in the copper tubing that runs between these components.
The refrigerant both receives and releases the heat as it does its work to lower or increase the temperature either switching liquid to gas or changing it back to liquid. The air handling unit draws indoor room air from various parts of the house through specialized return ducts.
This air is then pulled through a filter, where the air borne particles such as dust, dirt and lint are removed depending on how well the specialized filter has been built can also filter microscopic substances.
The quality filtered air then is routed to air supply tubes that carry it back to the receiving rooms or house.
The assigned air handler pushes warm air into the coil, the refrigerant then absorbs so much heat from the air that it turns into vapor. As a form of gas, it goes through to a compressor that pressurizes and presses it and moves it through the outdoor coil, which gets rid of the heat.
At this point, some units has pre-installed fans which also help to remove the heat. The refrigerant then passes through an expansion device that converts it to a low-pressure, low-temperature liquid, which returns to the indoor coil. And so the cycle goes.
Ductless air conditioning on the other hand can also be used to cool air in large scopes or areas, but instead of relying usually on duct work or specified channels, it uses individual wall units that remove moisture and hot air, and pump in cool air.
This form of air conditioning can be more environmentally friendly, as people can control the climate in individual rooms or groups of rooms, rather than using a single central unit to maintain a desired temperature.
Because temperatures can vary considerably across a structure, central air conditioning can use a lot of energy in its attempt to keep the air comfortable.
For large buildings, central air conditioning is critical, because the air can grow quite oppressive, especially in warm weather. Heat from the weather can make the building warm up, as can the heat from the bodies in the building, and moisture also accumulates as a result of respiration.
Using central air will keep a building comfortable for people to work in and make it more pleasant for visitors who may be entering the building, such as customers entering a department store.