Install units produced by the High Performance Rooftop Unit Challenge that meet the high performance rooftop unit specification
In January 2011, the U.S. Department of Energy (DOE) joined industry partners in the Better Buildings Alliance to release a design specification for 10-ton capacity commercial air conditioners, also known as rooftop units (RTUs).
The specification was a part of the High Performance Rooftop Unit Challenge initiative, to urge U.S. manufacturers to build and deliver innovative, competitively-priced, energy-saving rooftop units that meet the Commercial Building Energy Alliance-driven requirements of a high-performance specification. In May 2012, Daikin McQuay's Rebel rooftop unit system became the first to meet challenge. Four other manufacturers—Carrier, Lennox, 7AC Technologies, and Rheem—are participating in this challenge.
Units built according to the High Performance Rooftop Unit Specification are expected to reduce energy use by as much as 50% compared to the current ASHRAE 90.1 standard, depending on location and facility type. Nearly half of the cooling-conditioned commercial floor space in the U.S. features rooftop units. Businesses nationwide would save about $1 billion each year in energy costs if they replaced their 10-20 ton commercial units with units that meet this specification. DOE also developed a calculator to compare the energy and financial benefits of high-efficiency units to standard equipment.