What is HVAC and Why Is It So Important?

What is HVAC and Why Is It So Important?

06 August 2021
engineers inspecting and air conditioning system

As the weather becomes more unpredictable in the UK, more and more people are interested in controlling their indoor climate. As a result, HVAC is an increasingly common term, often used interchangeably with air conditioning. But what is HVAC? Is it the same as AC, and how can it keep your home or office at the perfect temperature?

We all want to live and work in a calm, cool, and dry environment. From the draughtiest warehouse to the smallest flats, air control is always important for keeping everyone comfortable and productive.


What is HVAC?

This is one of the most common questions our clients ask – “What does HVAC stand for?”


HVAC stands for heating, ventilation, and air conditioning. The term is shorthand for any buildings heating and cooling system. HVAC also often encompasses the ventilation system that allows moisture to escape, preventing mould and mildew.

An HVAC system might include the following, in different combinations:

  • Boilers
  • Ducts and moisture vents
  • Air conditioning units


While our clients often interchangeably use the terms HVAC and Air Conditioning, not all HVAC units include AC.

How Does HVAC Work?

In some cases, different HVAC components work independently. However, combined systems are more common than ever – this means that all components work together, including AC and central heating systems.

While your HVAC set-up can warm up your space in the winter and cool it down in the summer, it does so much more than that. It improves your air quality, reduces unwanted moisture from the space, and creates a happier, healthier environment.


Your HVAC system works on an ‘inside out’ principle – the internal systems differ from building to building, depending on needs, but they all rely on outdoor air. The HVAC ventilation system brings fresh air in from the outside in one of two ways.


  • Natural Ventilation – Simply put, natural ventilation is as easy as opening up a window! This type of ventilation doesn’t require any additional equipment, add-ons, or construction – it’s as easy as opening your doors and windows. Historically, natural ventilation was the only possible option, so many older buildings include air shafts and other natural air exchanges. If you live in an area with clean air, natural ventilation keeps your home’s air fresh and replenishes oxygen.However, if you live near a motorway or industrial district, natural ventilation is less than ideal, as all of those airborne toxins and particulates can come flooding inside.
  • Mechanical Ventilation – Mechanical ventilation uses electric mechanisms to bring air into and out of the building. In the past, architects always ensured that their designs had access to natural ventilation, such as doors, windows, and air shafts, which all allowed fresh air to come flooding indoors.However, modern buildings are more tightly sealed. To prevent mould, mildew, and cold draughts, they avoid natural ventilation practices, and this makes mechanical ventilation all the more important.These systems allow air to enter the building via a purpose-built air inlet unit, where it is then routed to the specific building areas it is needed. This air then blows dust, dirt, grime, and particles out of the system, reducing allergens and improving the overall air quality. Then, the air is either heated or cooled, and the system removes excess humidity.Now that the air is at the right level temperature and has the right amount of humidity, it travels through the ducts and vents and makes its way to the desired rooms or spaces.

What is Air Conditioning?

An air conditioning unit is a type of HVAC unit specifically designed to heat or cool the air. While some AC units also have a heating function (more on that below), most people use the term ‘AC’ to specifically refer to air cooling.

In the UK, we tend to refer to a unit designed to condition and cool the air as an air conditioner. On the other hand, we use the term HVAC unit for systems that that both heat and cool the air while removing moisture via air vents.

However, these days, nearly all AC units offer exceptional heating capacities. They use a heat pump system that reverses the refrigeration cycle to heat a space. In fact, many businesses are choosing AC units for heating instead of the more traditional “wet” systems. Even better, they use less energy, thus saving fossil fuels and going easier on the planet.


Different AC and HVAC Systems

Here are some of the most common AC and HVAC systems available in the UK:


  • AC or Heating Window Units – For many UK houses, a window air conditioner or heating unit is a smart choice. This small unit sits inside the windowsill and must vent to the outside. Of course, not every window style can accommodate a window unit, and you may have to customise the ventilation. While these units are usually quite small, they can pack a big punch. They’re also a good value, starting at just a few hundred pounds.
  • Central Air Unit (also known as Air Handling Unit – AHU) – Central air conditioners are a common solution for both cooling and heating and are great for large spaces. The system must be professionally designed and installed, and it must ventilate outdoors. This is a lifelong investment that will last decades in a home or commercial building.
  • Mini Split System – Mini-split systems are similar to central air units. However, they use refrigeration pipework instead of traditional ductwork, making them ductless systems. As a result, people often appreciate their appearance, as they have no ducts overhead, and they’re often more cost-effective than central air units.


Do you have questions about HVAC or AC?

Now that you know a little bit more about HVAC and AC, are you ready to have a new system installed in your home or business? If you have any questions, don’t hesitate to get in touch.