Capabilities

ERI Capabilities

The following ERI Standards and Addenda are currently available:

  • ANSI/RESNET/ICC 301-2014© “Standard for the Calculation and Labeling of the Energy Performance of Low-Rise Residential Buildings using an Energy Rating Index”.
  • ANSI/RESNET/ICC 301-2014 Addendum A-2015, Domestic Hot Water Systems, January 15, 2016
  • ANSI/RESNET/ICC 301-2014 Addendum E-2018, House Size Index Adjustment Factors, February 1, 2018
  • ANSI/RESNET/ICC 301-2014 Addendum G-2018, Solid State Lighting, February 2, 2018

Modeling Capabilities

The following building features/technologies are available for modeling:

  • Enclosure
    • Attics
      • Vented
      • Unvented
      • Conditioned
      • Radiant Barriers
    • Foundations
      • Slab
      • Unconditioned Basement
      • Conditioned Basement
      • Vented Crawlspace
      • Unvented Crawlspace
      • Ambient
    • Garages
    • Windows & Overhangs
    • Skylights
    • Doors
  • HVAC
    • Heating Systems
      • Electric Resistance
      • Furnaces
      • Wall Furnaces & Stoves
      • Boilers
    • Cooling Systems
      • Central Air Conditioners
      • Room Air Conditioners
    • Heat Pumps
      • Air Source Heat Pumps
      • Mini Split Heat Pumps
      • Ground Source Heat Pumps
    • Thermostat Type
    • Ducts
  • Water Heating
    • Water Heaters
      • Storage Tank
      • Instantaneous Tankless
      • Heat Pump Water Heater
      • Indirect Water Heater (Combination Boiler)
      • Tankless Coil (Combination Boiler)
    • Hot Water Distribution
      • Recirculation
    • Drain Water Heat Recovery
    • Low-Flow Fixtures
  • Mechanical Ventilation
    • Exhaust Only
    • Supply Only
    • Balanced
    • Energy Recovery Ventilator
    • Heat Recovery Ventilator
    • Central Fan Integrated Supply
  • Photovoltaics
  • Appliances
    • Clothes Washer
    • Clothes Dryer
    • Dishwasher
    • Refrigerator
    • Cooking Range/Oven
  • Lighting
  • Ceiling Fans

Accuracy vs Speed

The EnergyPlus simulation engine is like a Swiss army knife. There are often multiple models available for the same building technology with varying trade-offs between accuracy and speed. This workflow standardizes the use of EnergyPlus (e.g., the choice of models appropriate for residential buildings) to provide a fast and easy to use solution.

The workflow is continuously being evaluated for ways to reduce runtime without significant impact on accuracy. A number of such enhancements have been made to date.

There are additional ways that software developers using this workflow can reduce runtime:

  • Run on Linux/Mac platform, which is significantly faster by taking advantage of the POSIX fork call.
  • Use the --no-ssl flag to prevent SSL initialization in OpenStudio.
  • Use the -s flag to skip HPXML validation.
  • Do not use the --hourly-output flag unless hourly output is required.
  • Run on computing environments with 1) fast CPUs, 2) sufficient memory, and 3) enough processors to allow all simulations to run in parallel.