New Features

Highlights of this release (V8.1.0.009)

The highlights – improved and new features – are displayed by category.


  • Bug fixes throughout.


  • New data set for residential air-conditioner and heat pump performance curves.
  • 2013 ASHRAE Design Conditions files (Annual and Monthly) available from Helpdesk


  • Allow ZoneList for Steam and Other Equipment internal gains.

Windows and Daylighting

  • New option for windows based on ASHWAT model.
  • New zone daylight distribution model when using complex fenestration systems.
  • User-definable solar and visible spectrum weighting functions.

Zone and Surface Models

  • Dynamic clothing model for People thermal comfort.
  • Pre-calculated solar heat gains on inside faces of surfaces can be scheduled.
  • EMS actuators for outdoor air conditions for surface outside face heat transfer modeling boundary conditions.

Natural and Mechanical Ventilation

  • Cross ventilation natural ventilation model improved.

HVAC and Refrigeration

  • A unitary system with multispeed AC and multistage gas furnace
  • Comprehensive model for unitary HVAC systems.
  • Packaged thermal storage cooling coil.
  • Variable speed cooling tower based on Merkel model.
  • Zone forced air unit for evaporative coolers.
  • Central dedicated outdoor air serving fan coil units.
  • HVACTemplate for new comprehensive unitary system.
  • HVACTemplate for zone baseboard heaters.
  • HVACTemplate for heat and cool VAV terminals.
  • HVACTemplate for constant volume systems (non-unitary).
  • HVACTemplate for variable refrigerant flow equipment.
  • HVACTemplate for dual duct systems.
  • Expanded HVACTemplate options including ideal loads outdoor air and humidity controls, baseboard heat with all system types, fancoil controls, return fans, and fan powered VAV recirculation from plenum.

Controls and User Functions

  • Staged zone thermostat.
  • On/off setpoint managers for single zone heating and cooling.
  • User-defined plant equipment operation scheme based on EMS.
  • HVAC system optimal start control.
  • Operational fault modeling for air economizer control sensor offset.


  • Component model sizing diagnostics for easily comparing user-specified values to autosized values.


  • WeatherConverter produces 2013 design day files for appropriate locations.

Documentation and Guides

  • New document Plant Application Guide
  • Documentation has been updated for all documents.


  • Windows (XP, Vista, Windows 7, Windows 8, Windows 8.1) 32 and 64 bit versions
  • Linux (Ubuntu 12.04 and compatible) 32 and 64 bit versions; RHEL 5.0 compatible available on request via helpdesk.
  • Mac (10.7, 10.8 and 10.9) 64 bit versions
  • EnergyPlus V8.1 has been tested on all of these platforms
  • EnergyPlus does intensive computations, for high performance, computers should have a lot of memory and fast hard disk speeds.

And many other enhancements and speed improvements throughout.