What is a VAV in HVAC, and How Does It Work? 

An HVAC system has various parts working together to deliver per its design. Usually, a well-functioning HVAC facilitates heating, ventilation, and air conditioning. One of the most integral components that ensure it delivers as required is the VAV.

So what is a VAV in HVAC? A Variable Air Volume, VAV, controls air’s temperature and flow rate under distribution. The best way to look at the device is that it is an energy-efficient system that ensures you have a comfortable space. Typically VAV systems function best in commercial buildings to meet the needs of multiple building zones. A VAV does this while maintaining required flow rates. Within a VAV system are AHU and VAV boxes. Usually, every part of a space has a VAV box. VAV boxes have dampers that open and close to regulate airflow so that every zone point receives air at a specific temperature. Therefore, when trying to understand “what is a VAV in HVAC,” it’s essential to look at its features, how it works, and its benefits.

What Are the Features of A VAV System? A typical VAV system comes with a VAV box that houses the primary functional features of the system. Let’s look at what a VAV box is in HVAC by looking at its components. They include.

Air damper

The air damper is like a passageway that opens and closes as it passes through the system. Usually, the damper works under the control of the actuator. You can close the air damper if you are trying to make your unit energy efficient.

See also  15 Historical Reactions to Air Conditioning


An actuator controls the movement of air going into the building zones. It takes control of the fan and air and air damper.


Some varieties of VAV systems have coils while others don’t. This component heats and cools as air passes through the unit.

System Controls

The control in a VAV box is either direct digital, electronic, or pneumatic. Parts of the control is an airflow sensor that monitors airflow. Systems control ensures the proper amount of heating for various zones.


There are VAV boxes that have fans that work the same as series fans.

Types Of VAV Boxes

What are VAV types in HAV? There are various types of VAV boxes that have different applications. One of the most common types of VAV boxes is the standard VAV box which has a controller and actuator to control the damper. The controller in this type of VAV box has pressure sensors attached. The sensors also monitor temperature and humidity at the box’s inlets. Additionally, a wall sensor is attached to the controller, usually in the cooled or heated space. Another type of VAV box is the kind with a reheat mechanism. It has reheat coils for the air in the box before it goes into your space. Another type of VAV box is a fan-power-powered box, similar to a standard VAV box, although it has a fan. Whether the fan-powered VAV box is parallel or series depends on the fan’s position.

See also  10 Signs You are a Native Floridian

Role of VAV

One of the essential roles that a VAV plays is that it modernizes your spec. The system generally ensures the comfort of occupants in a zone. It is one of the things that elevate the value of your property and even make it more attractive for occupation. The system ensures a standard volume of conditioned air in a zone. Its delivery depends on the functionality of the various components of the system.

Benefits of VAV

The efficiency of your HVAC is highly dependent on the influence of the VAV on the entire system. The best way to understand what that means is to look at the benefits of a VAV.


Ensures temperature controlOperates silentlyEncourages energy efficiencyKeeps the compressor from wearing out too fastContributes to dehumidification

Maintenance for VAV

The best kind of maintenance for a VAV system is preventive maintenance. This maintenance aims to improve the system’s performance while protecting the entire unit. Usually, the manufacturer issues maintenance instructions. Maintenance of a VAV requires keeping a log of the things done to the system. It involves examining every part of the VAV box, which entails findings and the actions n performed to rectify issues. During maintenance, the following happens for the components in a VAV system. Check on the functionality of the airflow sensor in the VAV box and the damper. It’s also required to clean the sensor following the manufacturer’s instructions.Examine the controls depending on the tech type. For pneumatic types, check if it has leaks and if it’s electronic, ensure that it’s properly connected. Check the connection to the damper is correct if its Direct Digital ControlIn the damper, check for the seals and the alignment of the ducts. Also, examine the links for tension and lubricate following the manufacturer’s instructions.Clean the filters or replace them, especially in VAV that runs in fans. Check on the thermostat to ensure accuracy in calibrations and examine the controller’s signal.Clean the coil and look at the control valve to clear it of water leaks. The electrical connections must also be according to the manufacturer’s instructions.Re-tune the VAV system and perform any form of required maintenance for other VAV system components. It helps spot any potential issues as well and ensures repairs work.

See also  10 Most Influential West Palm Beach Residents


There is a lot to understand about “what is a VAV in HVAC.” It takes breaking down the parts that make up the system and knowing how it works to understand the VAV system truly. It is impossible to overlook having a VAV on your property for all its benefits.  Besides ensuring that your premise is comfortable, the VAV also increases the value of your property. The role it plays as part of your building is pretty straightforward. It’s one of those inventions that you can’t imagine what life would be like without.  Ensure that you schedule regular maintenance for the VAV with an expert to ensure there are no hick-ups when running it.

Skip to content