Roof top units, or RTUs, are a common fixture of commercial buildings. Nearly half of all commercial buildings across the nation take advantage of RTU technology, including office buildings, manufacturing facilities, hospitals, retail venues, and schools. Providing heating, cooling, and ventilation, RTUs have been servicing the comfort needs of large buildings since the early days of electro-mechanical air conditioning in the early 1900s.
Why Rooftop HVAC Systems?
During the early 20th century when these systems were introduced, most large businesses were located in crowded urban areas, where no room existed between buildings for the large outdoor units necessary to provide adequate cooling. To get around this issue, manufacturers designed systems that could access ventilation and operate from the roof.
Newer, albeit more efficient versions of RTUs are still in use today, remaining at the top of building where they take up less space, require less maintenance in the form of weed, grass and debris removal, and keep the grounds more attractive. This location also makes the systems less prone to theft and tampering, and allows for easier commercial HVAC maintenance without interfering with daily work routines. Because there are few space and design concerns with RTUs, expanding the heating, cooling, and ventilation capacity of these systems is also much easier due to their out-of-sight, limited use locale.
How Do Rooftop HVAC Systems Work?
Far more flexible in design today than they were just a generation prior, RTUs work a little differently than the standard home HVAC system. When cooling is necessary, RTUs draw warm air from within the building, cooling it with the help of a cooling coil, and redistribute it to the space below. When the outside air is cooler than the air inside, however, RTUs have the capability to save energy, taking advantage of outdoor conditions with the help of a specialized control system called an economizer. The economizer system opens up an air damper when outdoor air is cooler, reducing the need for the system to cool indoor air mechanically, and taking a 15-80% bite out of energy use depending on outside climate conditions. In addition, if a building requires added ventilation, outside air is always available. When paired with an occupancy or CO2 sensor, the system can bring in necessary fresh air on demand, responding to ventilation changes on an as-needed basis.
How Efficient are Rooftop Units?
While older RTUs are notoriously inefficient, newer RTU tech and retrofits offer far more reliable and efficient operation. With heating and cooling accounting for over 25% of the average commercial building’s energy use, such improvements in efficiency have a lot to offer in helping businesses cut energy costs, reduce their carbon footprint, and meet regulatory standards, not to mention in boosting productivity and protecting workers against temperature extremes.
Looking for opportunities to improve the efficiency of your rooftop unit? Contact the experts at H&H Commercial Services to schedule a system evaluation and learn more about opportunities for savings today.