There are so many things that every building needs to have. And one of the things that buildings need to have — especially the ones that are of the industrial or commercial kind — is a ventilation system.

What Is a Ventilation System?

Simply put, a ventilation system is a mechanical system in a building that brings in “fresh” outdoor air and removes the “contaminated” indoor air. To be more specific, a ventilation system is used to control exposure to airborne contaminants, such as fumes, dust, and vapors. Additionally, it is also used to maintain temperature and humidity at comfortable levels and reduce potential fire or explosion hazards.

Just like any kind of HVAC system, ventilation can be applied to a wide variety of situations. More often than not, this kind of system is predominantly required in workplaces and industrial buildings so as to provide a healthy and safe working environment. But in addition to these, ventilation is also important for residential buildings because it helps keep the air inside the house fresh and clean.

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What Are the Basic Types of Ventilation Systems?

Since ventilation systems are inherently complex machines, they can actually be categorized into several types. The type of ventilation system will highly depend on the nature of the building — particularly on whether it’s residential or industrial — and the following are some of the most common kinds of ventilation that are currently used.

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General Industrial Ventilation

General industrial ventilation, also known as dilution ventilation, is a ventilation system that reduces the concentration of the air contaminants or controls the amount of heat that accumulates in hot industrial environments by mixing (diluting) the contaminated air with fresh, clean, uncontaminated air. In other words, this kind of ventilation system controls pollutants generated at a worksite by ventilating the entire workplace. This means that to some degree, the pollutants are distributed throughout the entire worksite and could, therefore, affect people who are far from the source of contamination.

Because of this, dilution ventilation has its downsides. That said, it can be made more effective if the exhaust fan is located close to exposed workers and the makeup air is located behind the worker so that the contaminated air is drawn away from the worker’s breathing zone. Additionally, when used to control chemical pollutants, dilution must only be limited to situations where the amounts of pollutants generated are not very high, their toxicity is relatively moderate, workers do not carry out their tasks in the immediate vicinity of the source of contamination, and the emission rate of contaminants is relatively uniform.

Local Exhaust Ventilation

Local exhaust ventilation, also known as exhaust-only ventilation, is a ventilation system that captures contaminants at, or very near, the source and exhausts them outside. Because of the fact that this system consists only of an exhaust fan, outdoor makeup air is drawn into the building through leaks in the enclosure. Out of all the various kinds of ventilation systems, this is the one with the lowest installed cost and low operating cost.

Supply-Only Ventilation

Supply-only ventilation is the exact opposite of local exhaust in that it draws outdoor air into the house instead of exhausting indoor air. For that reason, indoor air escapes through the building enclosure and exhaust fan ducts.

Supply-only ventilation can be a dedicated system, or more commonly known as a central-fan integrated (CFI) system. With a CFI system, outdoor air is ducted to the return plenum of an HVAC air handler that draws in and distributes the outdoor air. Just like the local exhaust ventilation, supply-only ventilation also has a low installed cost, but for a CFI system, the electronically commutated motor may increase the initial cost and operating cost.

Balanced Ventilation

As the name suggests, a balanced ventilation system is a combination of exhaust and supply methods, thus roughly providing equal indoor exhaust and outdoor supply air flows (e.g. an exhaust fan combined with a supply fan or passive inlet vents). As such, a balanced system can include a heat recovery ventilator (HRV) or an energy recovery ventilator (ERV). Because of the fact that this ventilation system is a combination of two other kinds of systems, balanced ventilation unsurprisingly has a higher installed cost.

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What Are the Essential Components of a Ventilation System?

In order for a ventilation system to operate properly, it must have all its essential components. Understandably, since a ventilation system is a complex form of machinery, it has quite a number of these components, but to help you get started, here are the most essential ones.


This is the first and foremost component that is needed in a ventilation system. Generally speaking, fans are the components that are responsible for moving the air throughout the space — whether to let them out or let them in.

For a ventilation system, there are so many things to consider first in determining the size of the fan. To begin with, it’s not enough to just purchase a big fan. You must first really need to do precise calculations so as to figure out how much airflow is needed within a particular space. Aside from that, you must also consider whether your application requires a positive, negative, or balanced pressure. There are also different configurations of propeller shape, pitch, and size that will maximize the fan performance. And then there are also different ventilation setups to consider: forced supply/forced exhaust, natural supply/forced exhaust, forced supply/natural exhaust, and natural supply/natural exhaust.

Long story short, there are so many aspects that you need to deliberate on when you’re determining the size of the fan in your ventilation system.

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A louver is essentially a window blind or shutter with horizontal slats that are angled to admit light and air but to keep out rain and direct sunshine. The angle of the slats may be adjustable, usually in blinds and windows, or it can also be fixed.

For this reason, louvers are considered to be a necessity for ventilation systems, especially those that are installed in industrial plants. This is because occasionally, an industrial plant will want to combine gravity ventilation with a powered exhaust system. In this application, the ventilation system must be able to get air in the building but not outside elements of rain, dust, or insects. And so, louvers have to be installed in the system as well.

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Dampers may appear similar to louvers, but they actually perform a distinctly different function. Dampers are valves or plates that stop or regulate the flow of air inside a duct, chimney, VAV box, air handler, or other air-handling equipment. Because of this, dampers are more often than not used during an emergency event.


A dehumidifier is an electric appliance that is designed to remove excess moisture from the air. For this reason, if a customer needs a ventilation system that also removes moisture from the air in a contained industrial space, that system needs to have a dehumidifier in place. After all, dehumidifiers help maintain proper relative humidity for applications that are sensitive to moisture in the air.


A lot of the time, ventilation systems make a lot of noise, and this can be incredibly irritating and distracting to the people inside the building. Because of this, silencers have to be installed in the system as well since silencers offer much-needed relief from this noise. In other words, silencers are essential to maintaining worker comfort and lowering individual noise stress levels. In fact, silencers are incredibly beneficial that in some situations, they are required by the federal worker and property line regulations.

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Air Filters

Air filters are oftentimes used in conjunction with silencers, but unlike silencers, air filters don’t actually filter noise from the air. Rather, air filters remove particulates from the air while allowing the air to pass through them.

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Dust Collectors

Dust collectors actually have the same function as air filters; the only difference between them is that dust collectors are much more heavy-duty. For example, if the building has a cutting application that causes a lot of sawdust or metal particulates to enter the air, a dust collector will pick up the contaminant through a vacuum system and then places the air back in the space or outside after the particulates are removed. Because of this, some ventilation systems may require dust collectors in them, depending on where these systems will be installed.


Ventilation systems are some of the most incredibly important appliances in this day and age. And this is not surprising at all: after all, a ventilation system brings in “fresh” outdoor air and removes the “contaminated” indoor air. In other words, it helps control the exposure to airborne contaminants, such as fumes, dust, and vapors. In addition to that, it is also used to maintain temperature and humidity at comfortable levels and reduce potential fire or explosion hazards.

Because of the undeniable importance of ventilation systems, HVAC professionals like you have to be ready to provide this kind of HVAC system to those who need it. But before you can do that, you must first know all about the important components that make up a ventilation system. That way, you’ll understand better just how exactly this HVAC system works, thus allowing you to improve your service to your customers.

So, that is the purpose of this post: to educate you on the basics of ventilation systems. Hopefully, after reading this post, you’ll be able to use the knowledge you’ve just gained to enrich your own service to your customers. Hopefully, with this knowledge, you’ll be able to provide the best ventilation systems possible, and you will also be able to help your customers when they will experience ventilation problems.



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