Advance Rooftop-Unit Control (ARC) Retrofits: Field Demonstrations Validate Significant Energy Savings
Over the past ten years, a new Heating Ventilation and Air Conditioning (HVAC) retrofit technology
has established itself as a means to address the wasteful energy practices of rooftop units (RTUs)
which condition over 60% (39 billion square feet) of our nation’s commercial floor space1. RTUs are the
workhorse of small to medium commercial buildings because they are inexpensive, require minimal
engineering design and are easy to install.
Unfortunately, over their lifetime, RTUs are typically neglected. Now couple this with the fact that RTUs
have a large number of moving parts (e.g., belt driven fans, compressors, actuating dampers, etc.) and
because these are components purchased with the least cost in mind, maintenance and energy costs
can quickly derail the originally intended low-cost solution. Understandably, energy consumption and
longevity are not driving the design decisions of RTU manufacturers because over 90% of RTUs sold each
year are the code minimum systems for energy efficiency. The result is energy guzzling systems that
negatively impact a company’s bottom line.
Yet replacing RTUs before their end-of-life is not cost-effective. Purchasing a new, higher efficiency unit
plus the installation costs does not make financial sense until the RTU has achieved its expected fifteen
to twenty years of service. Facility managers find themselves in a catch-22. They want to improve their
company’s bottom line by reducing unnecessary HVAC energy spend and the frequency of maintenance service calls during the RTU’s last 5 to 10 years of service.