While unitary fans are typically found in schools, or more specifically, classrooms, they can be used in other industrial conditions as well. Basically, any situation where there are outdoor air requirements or room-by-room zoning can benefit from unit fans. Hospitals, nursing homes and other health centers are also very frequent clients of this system. As technology has progressed and improved the ventilation unit, its use remains as popular today as it was two decades ago.
They differ from fan coil units, unit heaters, and cabinet heaters in that they introduce conditioned outdoor air into the room or occupied space. With the sole purpose of ventilating air, whether or not a designer will apply univents to various buildings or facilities is determined after weighing the pros and cons. There are clear advantages and disadvantages to the use of unitary fans and these must be considered prior to application.
Advantages of using unitary fans:
- It only requires a single unit to provide heating and cooling, as well as ventilation, to a space.
- Very economical and energy efficient because they have the ability to provide room-by-room zoning.
- Outside airflow can be adjusted up to 100 percent outside air.
- They require very little physical space so they don’t take up a lot of space and aren’t obstructive.
- You can filter noise, odors, and other pollutants between adjacent spaces so there’s less risk of cross contamination.
- Energy efficiency in its operation, due, in part, to the economizers on the air side.
- It works to stabilize a building and increase its reliability because a failure does not affect the entire facility, it is usually limited to one room. Therefore, the entire building is not immobilized when there is a single failure.
- They are very easy and very cost effective to install.
- Maintenance is simple because they are easily accessible for filter replacement and other maintenance tasks.
- They are simple in design, and their controls and mechanics can be understood by maintenance personnel of various backgrounds and training.
- The versatility of the univent makes it very attractive. It can be controlled through an automation system that coordinates with other units or it can be standalone and simply controlled by a thermostat.
Cons of using unit fans:
- It can be loud. This is a problem that is not easily fixed.
- A Univent has a limited supply airflow which is approximately 2000 cfm per unit.
- The systems are part of the architecture of the room. They cannot be hidden and cannot be considered aesthetically pleasing. It is difficult to fit them into buildings where you want to hide the HVAC systems and components.
Often, when placed in the proper environment, a unit fan is a welcome component to a building’s HVAC system. Once the pros and cons of using them are weighed and all factors are taken into account, the unit fan becomes an effective and energy efficient addition to the structure.