Equipment
Rooftop Unit (RTU)
Definition
A self-contained commercial HVAC unit installed on a building's roof that provides heating, cooling, and ventilation to a defined building zone. RTUs package the compressor, condenser, evaporator, and air handler in one unit, making them the dominant HVAC solution for small-to-midsize commercial buildings.
Why It Matters for Your Business
RTUs are the most common commercial HVAC equipment in the U.S. (over 12 million installed per DOE). They account for 30–50% of HVAC energy use in light commercial buildings. Upgrading inefficient 10–15+ year old RTUs to modern high-efficiency models (IEER 12+) can cut HVAC energy use by 30–50%.
Frequently Asked Questions
What efficiency rating applies to commercial RTUs?
Commercial RTUs use IEER (Integrated Energy Efficiency Ratio) for cooling. ASHRAE 90.1-2019 sets minimum IEER requirements by unit size. Minimum IEER ranges from 11–14 depending on cooling capacity. High-efficiency RTUs achieve IEER 16+.
What is the typical RTU lifespan?
Commercial RTUs typically last 15–20 years with proper maintenance. Units beyond 15 years are often candidates for replacement — newer models can use 40% less energy and may qualify for utility rebates and ITC.