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NREL - National Renewable Energy Laboratory
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2005 R&D 100 Award Winner

TREAT with SUNREL™ Energy Analysis Software

Principal Developers: Michael Deru, Ron Judkoff and Paul Torcellini of National Renewable Energy Laboratory; Rick Gerardi, Andrew Fisk, and Lee Butler of New York State Energy Research and Development Authority (NYSERDA); Ian Shapiro, Maria Karpman, Nayden Nechev, Rob Rosen, and Mary Ellen Joy of Taitem Engineering, Inc.; and Gregory Thomas, Mark Lorentzen, Eric Woods, Ethan MacCormick of Performance Systems Development.

The National Renewable Energy Laboratory (NREL), along with the New York State Energy Research and Development Authority (NYSERDA) and its partners, created a tool that made it much easier for building professionals to perform accurate energy audits and reduce the impact of building energy use on the environment. That tool is TREAT 2.6 (Targeted Residential Energy Analysis Tools) with SUNREL™. TREAT with SUNREL is a comprehensive energy analysis tool that models building energy consumption and identifies the most cost effective energy efficiency upgrades for both single-family and multifamily buildings. Hundreds of auditors, engineers, and contractors have used it thousands of times to provide quick answers to energy use questions. Several innovations make TREAT with SUNREL stand out from other software; TREAT:

  • Matches actual fuel bills with energy models
  • Predicts occupant behavior so models are more realistic
  • Uses hourly weather data for more precise predictions
  • Offers whole-building solutions
  • Incorporates gains from solar radiation, lights, and appliances
  • Allows interactive energy savings calculations
  • Provides energy ratings for models
  • Provides room by room heat loss
  • Reports on health and safety issues
  • Tracks energy savings
  • Links users to outside data resources.

NREL developed SUNREL —the building energy simulation engine in TREAT — in the mid-1980s with several updates over time, and uses SUNREL to execute the heat and mass transfer calculations required for a detailed energy simulation of a building. The tool gives building performance contractors and energy auditors a competitive edge in the areas of accurate energy-use analysis, energy efficiency improvement options and customer confidence.

NYSERDA sponsored the development of TREAT, a simple but sophisticated software interface, that makes it easy for auditors to perform accurate energy audits and to prioritize building upgrades that improve the energy efficiency of buildings. NYSERDA now requires auditors to use TREAT for their Home Performance with Energy Star® and New York Energy Star Labeled Homes Programs. NYSERDA also uses TREAT exclusively for its Assisted Multifamily Program and its Residential Technical Assistance Program. But the use of TREAT extends beyond New York — auditors from California to New Hampshire use it. Washington State just selected TREAT for use in its low-income weatherization program. In addition, TREAT is the only pre-approved software suitable for all DOE Weatherization building types.