HVAC is an industry, a career, and equipment. Most homes and almost all commercial buildings use HVAC services and parts. But what exactly is HVAC?
This article will look at the terminology, definitions, and meanings of the HVAC world. We will explain everything you need to know to understand what HVAC stands for.
What is HVAC?
HVAC, by definition, is an acronym that stands for Heating, Ventilation, and Air Conditioning. The term generally refers to your home, vehicle, or business’s heating and cooling system. HVAC equipment comes in many forms, including central ACs, mini-split systems, windows, and portable ACs, as well as many others.
Any device that can cool the air, heat the air, or ventilate the air in your home or car is a part of the HVAC family of systems.
How Do HVAC Systems Work?
The basic idea of an HVAC system is to move air through the space while removing the heat of the air in one space and moving it to another. Depending on the settings, this means your living space will become cooler or warmer.
Using refrigerant through copper lines, the AC portion will pump high presser liquid refrigerant to an evaporator where it absorbs the heat from the air being blown over the lines. The air becomes super cooled and is then blown into the living space to keep it cool.
In heating mode, the air is blow over heated coils that pick up the heat and transfer it to the living space. For ventilation, neither heating coils or refrigerants are used, and a “fan-only” mode is used to move the air, recirculate and bring fresh air into the space without changing its temperature.
The History of the HVAC System
It is believed that the first attempts to cool a living space started in ancient Egypt and China, where wet items (rags or clothing) were hung in areas like doors and windows so the air would become cooled by blowing through the wet garments.
Fans were invented in China using a hand crank to move paddles, making the force of moving air stronger. Eventually, large blocks of ice were used to cool the air the fan blades were creating, effectively being the first air conditioners.
By the turn of the 19th century, this process became automatic, resulting in what we would consider a modern air conditioner today. Most of these “air coolers” were large and bulky and extremely expensive.
The idea of moving water or air to cool or add heat to a space can easily be traced as far back as ancient China and Rome with the use of aqueducts and river channels. A far cry from the energy-efficient and affordable units we use today.
Modern Air Conditioner Trends
According to market research, the HVAC industry is one of the most significant growth economies in the United States. It is projected to continue growing at an average rate of almost 10% per year. This is compared to the average industry growth over the same period of less than 4%.
HVAC is currently a $16 billion industry in the US alone, with 48% of that growth being in the residential market. New energy efficiencies are being called for, which is putting a higher demand on HVAC technology and skilled technicians.
Initiatives are in place to give rewards for consumers that purchase energy efficient HVAC systems by offering discounts, rebates, and lower energy rates if they use energy efficient machines.
These trends look to continue to move forward and continue to grow well above industry averages, even around the world.
Types of HVAC Systems
What are the various types of HVAC systems? Let’s take a look at the modern examples you are most likely to come across.
Heating and Cooling Split Systems
Split systems are the most common HVAC units in residential areas. You may know them as “central heating and air” units. These are “split” systems because the condenser and evaporator units are separated.
The condenser unit houses the compressor, which pressurizes the refrigerant and removes the heat from the lines. It is found outside the home. The evaporator unit is inside the home and is responsible for cooling the air or heating the air by blowing it over the chilled refrigerant lines or heating coils.
Hybrid Split System
A hybrid system is also known as a dual-fuel system. Most of these types will use electricity and natural gas as heating options, automatically switching between the most efficient fuel source for the demand.
Instead of an evaporator and condenser, most hybrid systems will use an air handler and a heat pump to heat or cool the interior of the home.
Duct Free (Mini-Split)
Duct free systems, also known as ductless mini-splits, use a heat pump outdoors and a miniature air handler in a single room. If you have multiple indoor units, it is known as a multi-stage mini-split.
Mini-split systems are growing in popularity because of their simple install and high energy efficiency ratings.
Packaged Heating and Air
A packaged heating and air system is a space-saving option when the home or space doesn’t have enough room to hold an entire split system. The heating and cooling portions of the packaged system are combined into a single unit and placed outside (usually on the roof) to that only the air ducts and vents are routed into the walls and rooms.
Main Components of any HVAC System
Almost without fail, every type of HVAC system will contain the following components. Let’s take a moment to learn more about them.
The heat exchanger, as its name implies, transfers the heat collected by the system from one place to another. In the HVAC industry, this means removing the heat from the air and putting it into the refrigerant to cool the home or adding the heat to the air to heat the home.
The blower motor is a part of the air handler or evaporator unit. It is positioned between the refrigerant coils and the heating elements (in most cases). When turned on, the blower motor will pull the air through the coils (in cooling mode) and push the cold air through the ductwork.
In heat mode, the blower motor will force the air over the heating elements and into the ducting to raise the temperature in the home.
In gas-fueled systems, the combustion chamber is the metal housing where the gas is ignited, producing a flame (or flames) that is used to heat the air for distribution around the home.
The condenser unit is the outside unit in a split system that cools the refrigerant from a vapor buy removing the heat as it travels through the coils. The compressor is inside the condenser unit and works to pressurize the vapor into a high-pressure liquid that is supercooled before returning it to the evaporator unit inside the home.
The evaporator unit receives the high-pressure, super cooled refrigerant from the compressor. In the evaporator coils, the heat from the air is absorbed, resulting in a heat exchange. This exchange causes the air to become chilled and the refrigerant to expand back into a heated vapor, where it is sent to the condenser unit to become chilled and pressurized once again.
The thermostat is the control center for the HVAC system. It will have a small thermometer to determine the temperature of the air around it. Based on this temperature and the control settings you have enabled, the system will turn on or off and heat or cool the room. The thermostat is responsible for shutting the system off when the temperature is reached and turning it back on when the temperature falls too far out of specs.
Frequently Asked Questions
When did HVAC systems become standard in homes?
The HVAC systems we know today became standard at the end of World War II. In the early 1950s, window air conditioners were being sold at a rate of about 1 million units per year. By the 1970s, central air systems were in demand, and the industry continued seeing growth each year since.
What is the difference between HVAC and air conditioning?
Air conditioning is accomplished by chilling the air before it is sent into the space. This can be done by several types of units that don’t have any other capabilities. An HVAC system will heat, cool, and circulate the air, depending on mode selection.
How do I start a career in HVAC?
If you want to become a certified HVAC technician, you will need to become EPA 608 certified and have a certification from an accredited HVAC training school or program or serve through an HVAC internship program.
How long does it take to learn HVAC?
Depending on your availability and the method of learning you go through, you can become HVAC certified in as little as 4 months. However, the standard certification process generally takes 12 to 24 months for completion.
Do HVAC technicians make good money?
Depending on the experience, technician level, and years in the industry, you can potentially earn between $32,000 and $54,000 per year as an HVAC technician. This will increase or decrease depending on your location, the company you work for, and other factors.
Is a water heater considered HVAC?
Technically no. A water heater is a part of the home plumbing system. However, some HVAC systems use heated water for operation and will use a type of water heater known as a boiler to operate. In these instances, the water heater becomes a part of the HVAC system.
How much does a new HVAC unit cost?
According to Home Advisor, a new, complete install of an HVAC system will cost between $5,000 and $10,000. This will also be determined by the type of system you purchase, the amount of labor to do the install, and how much you are charged for labor per hour.
Is HVAC a fun job?
HVAC can be an exciting and entertaining career. In the field, there are many different systems, with a lot of various problems to diagnose, solve, and repair. The HVAC technician rarely has a workday that is the same as another. The job is always moving and has new experiences every day.
Are HVAC inspections dangerous?
In general, HVAC inspections aren’t dangerous. There are hazards, of course, and the potential for danger or injury is always there. Unless there is a suspected problem with the heat exchanger or compressors, though, the overall danger factor is fairly low.
What is involved in an HVAC inspection?
The process should last at least an hour per zone. During the inspection, all system parts will be visually inspected, monitored, and metered. Fans, motors, and electrical components are tested. Coils and wiring are metered for connectivity, leaks, and supercooling/heating. The inspection will also test drainage, airflow, temperatures, and overall operation of the system.
Heating, Ventilation and Air Conditioning, also known as HVAC, is an intricate system that works to keep our homes, cars, and offices at an ideal temperature. Without these systems, we wouldn’t be able to experience year-round comfort in our own homes.