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RTU Comparison Calculator

About the Comparison Calculator

The Rooftop Unit Comparison Calculator (RTUCC) compares high-efficiency rooftop air conditioners to standard equipment in terms of life cycle cost. This web application provides an alternative to complicated building simulation models while offering more detail than simplified estimating tools that are commonly available. While simplified tools are typically based on full-load efficiencies and full-load equivalent operating hours, the RTUCC accounts for local climate and partial-load as well as full-load efficiencies.

The Comparison Calculator assists decision-making regarding the purchase or replacement of packaged rooftop air conditioning equipment by estimating a product´s lifetime energy cost savings at various efficiency levels. Other key features include the following:

  • The calculator is fully web-based.
  • Menu-driven format is easy to learn and use.
  • Quickly estimates life cycle cost, simple payback, return on investment, and savings-to-investment ratio.
  • Simulates operation under specific climate conditions at any of 237 U.S. locations selected by the user.
  • Reflects user-specified air-conditioning requirements and building-use patterns.
  • Results are easily downloaded as graphic files and tables for further analysis and presentation.

The results obtained with the Comparison Calculator will be useful to facility managers, financial officers, energy management professionals, air conditioning contractors, and other decision makers interested in maximizing both energy-efficiency and cost-effectiveness of cooling system investments. The calculator provides energy and cost estimates suitable for comparison purposes. The RTUCC was not designed to replace building load simulating software for heating and cooling systems design. Due to the dynamic nature of building heating and cooling, actual energy use will vary depending on the application.

The Comparison Calculator is a screening tool that estimates a product's lifetime energy cost savings at various efficiency levels. It provides energy and cost estimates suitable for comparison purposes only. The Comparison Calculator is not designed to replace building load simulating software for heating and cooling systems design. Actual performance and costs will vary depending on specific operating conditions. Neither the U.S. Department of Energy nor Pacific Northwest National Laboratory is responsible for any adverse outcome associated with results generated by the Comparison Calculator.

Rooftop Air Conditioner

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