While unit ventilators are generally found in schools, or, more specifically, in classrooms, they may be used in other industrial conditions as well. Basically, any situation where there are outdoor air requirements or room-byroom zoning can benefit from unit ventilators. Hospitals, nursing homes and other health care facilities are also very frequent customers of this system. As technology has progressed and improved upon the unit ventilator, its use is still as popular today as it was two decades ago.
They are unlike fan-coil units, universitycafe unit heaters and cabinet heaters in that they introduce outdoor air that is conditioned, 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 assessing the pros and cons. There are distinct advantages and disadvantages to using unit ventilators and they must be taken into consideration before application.
Pros of using unit ventilators:
Only require a single unit to provide both heating and cooling, as well as ventilation, to a space.
Very economic and energy efficient because they have the capabilities to provide room-by-room zoning.
Outdoor airflow can be adjusted up to 100 percent outdoor air.
Require very little physical space so they do not take up a lot of room and are not obstructive.
Can filter noise, odors and other contaminants between adjacent spaces so that there is less risk of cross contamination.
Energy efficient in their operation, due, in part, to airside economizers.
Act to stabilize a building and increase its reliability because a failure does not affect the entire facility, it is usually confined to one room. Therefore, the entire building is not immobilized when there is a single failure.
Are both very easy and very cost effective to install.
Maintenance is simple because they are easily accessible for filter replacements and other maintenance tasks.
Are simple in design and their controls and mechanics can be understood by maintenance personnel of varied backgrounds and training.
The versatility of the univent makes it very attractive. It can be controlled through an automation system that is coordinated with other units or it can stand alone and simply be controlled by a thermostat.
Cons of using unit ventilators:
Can be noisy. This is a problem that is not easily remedied.
A Univent has a limited supply airflow that is about 2,000 cfm per unit.
Systems are a part of the architecture of the room. They can not be hidden and they may not be considered aesthetically pleasing. It is difficult to adapt them to buildings where it is desired that HVAC systems and components not be seen.
Often, when placed in the appropriate environment, a unit ventilator 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 consideration, the unit ventilator becomes an energy efficient, effective addition to the structure.
Greg McNary has over 25 years experience in the HVAC industry in various positions including service, sales, and management. He is the marketing and operations manager for Air Distributors Company, Inc., a distributor for McQuay Parts, AAF/Herman Nelson Parts, GE Zoneline, and Applied Comfort Products.