What is HVAC? | HVAC Systems and How They Work (2023)

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Its HVAC system provides you with indoor comfort throughout the year. (Did you just think, "Wait, they lost me on the first set. What is HVAC?" 🤔 You've come to the right place.)

Learn how HVAC systems work and what this fast growing industry is all about.

What does HVAC mean?

HVAC (Heating, Ventilation and Air Conditioning) is the use of technology to treat air. HVAC is a generic term for systems, equipment, manufacturers, contractors, and technicians that:

  • heat the air in the room.
  • Fresh air from the room.
  • It moves air from room to room, outside in or inside out.
  • Keep indoor air comfortable and healthymoisture content (moisture).
  • Clean (or clean)indoor air

What is the air conditioning used for?

HVAC ensures more comfortable indoor air. HVAC systems increase the temperature, humidity, and air quality of indoor living and gathering spaces.

An HVAC system also adds a buffer between a building and the elements. Without an HVAC system, the temperature inside a building would feel just as hot, cold, humid, or dry as the air outside.

Residential versus commercial HVAC

Residential HVAC is the treatment of air in homes, apartments, RVs, and other living spaces. Smaller systems can heat and cool a single room, while a centralized system is designed for entire houses.

Commercial HVAC is for corporate offices, industrial buildings, and retail stores. Commercial HVAC systems work like residential units but are much larger because they handle larger spaces.

air conditioning: heating

Indoor warm heating systems. They generate or transfer heat from a central source and then disperse it throughout the room.

Stoves are the most popular heating system in the United States. Although heat pumps are less common, they are becoming more and more popular.Anti-inflationary Lawthis cuts costs drastically. Heating systems use various methods to bring warm air into a room or building.

heat distribution methods

Heat distribution methods ensure that the warm air actually reaches the space it is intended to heat. Although forced ventilation is the most common method in the US, there are options for ductless rooms.

convection heating

A forced air system uses a series of ducts and vents to supply warm air. In short, this is how it works:

Step 1️⃣: Air intake grills draw indoor air into the recirculation system.
Step 2️⃣: A central heating source, usually a stove, heats the air.
Step 3️⃣: Hot air leaves the heat source and flows through a network of tunnel-like metal structures called ducts.
Step 4️⃣: Air reaches another set of vents. Return vents distribute air back into the room.

Ductwork is a common feature of commercial spaces and most modern homes, which is what makes forced-air heating so popular.

radiant heat

radiant heating systemsUse download to supply hot air. There is a heat source under the ceiling, walls or floors. The heat source emits energy and heats the surrounding air on contact.

Radiant heat is generally based on an electric or gas source, such as a boiler, or a hydronic (water-based) fuel source such as a water heater.

The heat source heats the steam, air or water filled pipes below the floor. As a less invasive option, heated panels can be installed on the ceiling or on the walls.

Radiant heat is energy efficient but less common due to high installation costs.


Geothermal energy uses the ground as a heat source. A few meters below the earth's surface, the ground absorbs the sun's rays and maintains the temperature almost constant.

The pipes are buried in the ground where they absorb heat. The pipes carry the heat to a heat pump, which transfers and distributes the heat.

(Video) What is an HVAC System and How Does It Work?

Geothermal heat pumps are becoming more popular as geothermal energy is considered a renewable resource. However, it is expensive to install.

Heating systems

A heating system is a device that converts a heat source (or fuel) into heat. Heating systems use a variety of methods to generate or transfer energy.

See some of the most popular heating methods and how they work.


What is HVAC? | HVAC Systems and How They Work (1)

Akilnit is the most common heating method in the United States. Furnaces can convert gas, propane, oil, or electricity into heat.

the mostovensThey are central HVAC systems, which means they generate heat in one place and channel the hot air through ductwork.

Product Legends Section

  • What is HVAC? | HVAC Systems and How They Work (2)

    did you know

    The oven was patented in 1919.


Highlights from product professionals.

  • Low acquisition costs
  • Ideal for extreme climatic zones
  • Electric models are energy efficient


Highlights of the product cons.

  • High operating costs
  • Dry room air

Our best stoves

(Video) HVAC Training - Basics of HVAC

heat pumps

What is HVAC? | HVAC Systems and How They Work (3)

Aheat pumpIt is air conditioning and heating in one. Heat pumps come in gas and electric models.

Heat pumps do not generate heat like an oven does. you transfer it In heating mode, a heat pump extracts heat from the air, water or soil outside and brings it inside.

In cooling mode, a heat pump works in reverse, drawing in warm indoor air and transporting it outdoors.

Product Legends Section

  • What is HVAC? | HVAC Systems and How They Work (4)

    did you know

    Heat pumps are most commonly sold in North Carolina and South Carolina.


Highlights from product professionals.

  • efficient energy
  • Low running costs
  • Double climate system


Highlights of the product cons.

  • Not ideal in extreme climates
  • High unit costs

Our best heat pumps

(Video) How Chiller, AHU, RTU work - working principle Air handling unit, rooftop unit hvac system

air conditioning: ventilation

Ventilation introduces air into an interior space. A strong ventilation system improves indoor air quality and promotes smooth, even airflow.

  • Air purifiers clean and deodorize the air.
  • Humidifiers and dehumidifiers keep humidity at safe and healthy levels.
  • Fans and blowers keep the air moving.

HVAC systems use a combination of natural and mechanical ventilation to keep the air healthy and comfortable.

natural ventilation vs. mechanics

Natural ventilation is an uncontrolled flow of air. Think of the wind or air flowing through an open window or door. Indoor spaces rely on natural ventilation to add fresh oxygen to the air.

Mechanical ventilation is a flow of air controlled by equipment or a device. HVAC systems use fans, motors, and blowers to move and distribute air.

air filter

Use of forced air and central HVAC systemsair filter. Filters capture airborne germs, dirt, debris, and even odors.

💡Tip: To improve indoor air quality, make sure your central HVAC system has itcorrect filter size.

Air conditioning: air conditioning

Air conditioning cools the interiors.87%of American homes have air conditioners, making them more popular than stoves and heat pumps.

Air conditioners remove heat and humidity from the air in your home. The heat is converted from a gas to a liquid and transported outside, cooling the air in the room.

Take a look at the different types of air conditioners.

Central air conditioner

Central air conditioning is used to cool the entire house. Central air conditioners use the same forced air circulation system as furnaces to distribute air.

A tunnel of ducts moves the air and vents distribute the air in each room. There are two common types of central air conditioners.

split system

A split system air conditioner has an indoor unit (air handler) and an outdoor unit (condensing unit).

The outdoor unit accumulates heat. The indoor unit or air handler circulates the air and passes it through a filter.

wrapped system

A packaged system is also known as an on-premises HVAC system. It works like a split system, but all the parts are contained in a single outdoor unit.

The outdoor unit combines both elements of a split system into one. Some models of compact air conditioners also serve as heat pumps or stoves.

Packaged systems are ideal for homes with limited interior space. Because there is no indoor unit, compact systems are also quieter than indoor split systems.

Mini split

Mini splits are ductless air conditioners. The outdoor and indoor units are connected via a series of cables, making it a great option for homes without sewer or central HVAC.

An indoor unit or air handler is mounted on the wall, ceiling, or floor. The air handler supplies cool air directly into the room.

Single zone minisplits pair an outdoor unit with an indoor unit. For cooling a single room or an addition to a home, they are a cost-effective option.

(Video) How Air Handling Units work AHU working principle hvac ventilation

Multizone minisplits or multisplits connect a single outdoor unit to several indoor units. You can adjust the temperature of each room individually (known as zoning).

window unit

window air conditionerit is a cost-effective option for individual room cooling. Window units are electric and most plug into a standard 115v outlet.

We recommend window units for apartment living and for additional cooling. Over time I got window unitscalmer and more attractive.


What is the difference between AC and HVAC?

Air conditioning or refrigeration is only one aspect of the HVAC industry. HVAC also includes heating and ventilation, which uses various systems, such as furnaces. All air conditioners are HVAC systems, but not all HVAC systems are air conditioners.

Where can I buy HVAC equipment?

You can purchase central HVAC systems on the manufacturer's website or through a local contractor. Some contractors have an exclusive contract with an HVAC manufacturer, so they only sell products from one brand. Other contractors sell products from multiple HVAC brands. Mini splits and window units are available through third-party vendors like Amazon.

What is HVACR?

The R in HVACR stands for cooling, or keeping something cooler than room temperature. Refrigerant is the gas-to-liquid component in air conditioners, heat pumps, and refrigerators.

What are the best HVAC brands?

Trane, Lennox and Carrier are considered elite HVAC manufacturers. High-quality, durable products and strong brand awareness add to their high cost. Rheem, York, and Amana have impressive catalogs, but they are often cheaper than the elite brands.

How do I find a good HVAC contractor?

When you start looking for a contractor, get bids from at least three companies. The prices vary a lot, even in the same place. Ask each contractor if they are licensed to operate in your state. To verify this, you can request a copy of your state license. The contractor must also be bonded and insured. If a technician is injured at your home, insurance will cover the damage.

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1. HVAC Training - (Heating Ventilation & Air Conditioning)
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5. Fundamentals of HVAC - Basics of HVAC
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6. How a Home AC Works For Dummies
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