High Performance Rooftop Unit Challenge

Key Resources

In January 2011, the U.S. Department of Energy (DOE) joined industry partners in the Better Buildings Alliance (BBA) to release a design specification for 10-ton capacity commercial air conditioners, also known as rooftop units (RTUs). The specification was issued as an "RTU Challenge," since it aimed to catalyze the market introduction of cost-effective, energy-saving RTUs that would significantly outperform any models that were currently available. The BBA includes an array of building owners that purchase large volumes of RTUs, so their issuance of a specification outlining common performance requirements and desired features represents a powerful demand signal to manufacturers.

RTU Challenge Update Summer 2012

DOE announced on May 24 that Daikin McQuay's Rebel rooftop unit system is the first to meet DOE's Rooftop Unit (RTU) Challenge. Five manufacturers—Daikin McQuay, Carrier, Lennox, 7AC Technologies, and Rheem—are participating in this challenge to commercialize highly efficient commercial air conditioners that satisfy a DOE-issued specification for energy savings and performance.

The final participant list was announced by Dr. Kathleen Hogan, deputy assistant secretary for Energy Efficiency, at the Energy Department's first Efficiency Forum, a public stakeholder engagement event hosted by the National Renewable Energy Laboratory in Golden, Colorado

The companies have until April 1, 2013 to submit a product for independent evaluation according to the specification. When built to meet the specification, these units are expected to reduce energy use by as much as 50% over current standards. Nationwide, if all 10 to 20 ton RTUs met the specification, businesses would save over $1 billion each year in energy costs, helping American companies better compete on a global scale.

Read the full announcement.

Enormous Energy and Cost Savings Potential

RTUs are used in nearly half of all cooling conditioned commercial floor space in the United States. RTUs built according to the 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. Nationwide, if all 10-20 ton commercial units were replaced with units built to this specification, businesses would save about $1 billion each year in energy costs. DOE developed an RTU Comparison Calculator so one can easily compare the energy and financial benefits of high-efficiency units to standard equipment.

Primary features of the specification include:

  • High-performance Integrated Energy Efficiency Rating (IEER) of 18
  • Direct digital controls
  • Operational fault detection

Role and Opportunity for BBA Participants

The RTU Challenge aims to benefit all stakeholders that utilize 10-ton RTUs, so resources like the specification and RTU Comparison Calculator are freely available and promoted via webinars and other public engagement events. As partners in this initiative, participating BBA members have the added benefit of:

  • Informing the development of the specification
  • Leveraging DOE technical assistance to conduct demonstrations of successful RTUs
  • Participating in unique public relations opportunities, such as the Efficiency Forum, which highlight successes that can be replicated by the broader commercial sector.

As a signal of their support for the RTU Challenge, participating BBA members issued the following statement:
"We will strongly consider purchasing units that meet the specification, are consistent with our cost-effectiveness criteria, and align with our procurement timeframes. We look forward to working with the manufacturers and DOE to factory witness tests of prototype units that meet this specification. We understand that DOE has committed resources and technical assistance to help U.S. manufacturers design and develop products to meet this specification. We look forward to the near-term market introduction of reliable, energy-efficient and competitively priced rooftop units which increase the energy efficiency of the sector."

Participating BBA members include:

  • Cleveland Clinic
  • Costco Wholesale Corp.
  • Edens & Avant
  • Grubb & Ellis Co.
  • Gundersen Lutheran Health System
  • InterContinental Hotels Group
  • Lowe's Companies, Inc.
  • Macy's, Inc.
  • McDonald's Corp.
  • Publix Super Markets
  • Target Corp.
  • The Home Depot, Inc.
  • Walmart Stores, Inc.
  • Yum! Brands

Consider joining the BBA if you are interested in this and similar energy saving projects!

Role and Opportunity for RTU Manufacturers

In order to participate in the RTU Challenge, manufacturers of RTUs (not individual component suppliers) had to satisfy an initial DOE screening by May 15, 2012. During the screening, DOE technical experts reviewed preliminary product details to determine if the manufacturer was on a reasonable path to have a complete product ready for full DOE evaluation by April 1, 2013, and available to the market thereafter. The full DOE evaluation entails an in-depth review of certified IEER performance and any deviations from the specification, and only one candidate product per manufacturer can be submitted. If the full evaluation is satisfactory by this deadline, DOE will recognize the product for meeting the RTU Challenge.

Public relations activities are being pursued at various stages to ensure that key developments and resources reach a broad audience. Products that meet the RTU Challenge may also be eligible for demonstrations in BBA and federal facilities, and their performance may be characterized in DOE decision tools so that potential customers can evaluate these products relative to typical RTUs.

Visit this page again for regular updates on the RTU Challenge.