What’s the Difference between AC and HVAC?

You may say tomato and I may say to-MAH-to but we’re talking about the same fruit. When we compare apples to oranges we’re saying that those two fruits are different. So where does AC vs. HVAC fall in these two examples: same or different? The answer is neither, exactly.

Let’s explain. HVAC is an acronym for Heating, Ventilation and Air Conditioning while AC simply stands for that last part, Air Conditioning. In other words, when we refer to AC we’re talking about a system that cools the air in your home. However, when we talk about HVAC, we are saying there are three functions combined into one system: heating, cooling and ventilation. Dehumidification is also a function of an HVAC system.

You probably don’t realize that in order to perform its function of cooling, an HVAC system moves heat from inside your home to outside. Then, for heating it reverses the flow of air and moves heat from outside to inside. That said, AC is often used to mean your entire HVAC system because your air conditioner is probably a “heat pump” and without a venitilation fan you have nothing.

But what about the V for Ventilation?

Ventilation is an often overlooked, yet crucial aspect of operation for an HVAC system. It would be easy to assume that ventilation is all about moving air through air ducts for distribution into an entire building. While that is true, in order to accomplish that movement, ventilation also refers to the system’s ability to reduce air infiltration and maintain pressure relationships between spaces.

Those functions are what make room air distribution possible and without the distribution of air, the heat or cool would not travel.  Ultimately, air movement is what makes your entire system work.

Major components of your HVAC System

In most cases there is an outdoor unit (the compressor) and an indoor unit (the fan or fan coil). Sometimes they are packaged outside the home. Sometimes the fan coil unit is in a closet, sometimes in an attic. Even with mini split systems there is a compressor outside the home and a fan inside the home.

So we are left with the word “SYSTEM” which is key. “AC System” almost always means “HVAC System.”