Outputs

Upon completion of the ERI calculation, summary output files and simulation files are available. See the sample_results directory for examples of these outputs.

Summary Files

Several summary files described below are found in the results directory.

ERI_Results.csv

The ERI_Results.csv file includes the ERI result as well as the high-level components (e.g., REUL, EC_r, EC_x, IAD_Save) that comprise the ERI calculation. The file reflects the format of the Results tab of the HERS Method Test spreadsheet.

Note that multiple comma-separated values will be reported for many of these outputs if there are multiple heating, cooling, or hot water systems.

See the example ERI_Results.csv.

ERI_Worksheet.csv

The ERI_Worksheet.csv file includes more detailed components that feed into the ERI_Results.csv values. The file reflects the formate of the Worksheet tab of the HERS Method Test spreadsheet.

Note that multiple comma-separated values will be reported for many of these outputs if there are multiple heating, cooling, or hot water systems.

See the example ERI_Worksheet.csv.

ERI______Home.csv

A CSV file is written for each of the homes simulated (e.g., ERIReferenceHome.csv for the Reference home). The CSV file includes multiple sections with different outputs.

1. Annual Energy Consumption by Fuel Type. Current fuel types are: “Electricity”, “Natural Gas”, “Fuel Oil”, “Propane”. It also includes an “Electricity: Net” field that incorporates any renewable generation.

2. Annual Energy Consumption By Fuel Type and End Use. Current fuel types are: “Electricity”, “Natural Gas”, “Fuel Oil”, “Propane”. Current end uses are: “Heating”, “Heating Fans/Pumps”, “Cooling”, “Cooling Fans/Pumps”, “Hot Water”, “Hot Water Recirc Pump”, “Hot Water Solar Thermal Pump”, “Lighting Interior”, “Lighting Garage”, “Lighting Exterior”, “Mech Vent”, “Whole House Fan”, “Refrigerator”, “Dishwasher”, “Clothes Washer”, “Clothes Dryer”, “Range/Oven”, “Ceiling Fan”, “Plug Loads”, “PV” (negative value for generation).

3. Annual Building Loads. Values are reported for heating, cooling, and hot water. Heating and cooling loads include duct losses. Hot water loads are grouped into A) Delivered (i.e., the load associated with hot water delivered), B) Tank Losses, C) Desuperheater, and D) Solar Thermal. The Delivered hot water load includes any contributions from desuperheaters or solar thermal systems.

4. Annual Unmet Building Loads. Values are reported for heating and cooling. These numbers reflect the amount of heating/cooling load that is not met by the HVAC system, indicating the degree to which the HVAC system is undersized. An HVAC system with sufficient capacity to perfectly maintain the thermostat setpoints will report an unmet load of zero.

5. Peak Building Electricity. Values, in Watts, are reported for the summer and winter seasons. The summer season is defined by the hours of the year when the cooling system is operating, and the winter season is defined by the hours of the year when the heating system is operating.

6. Peak Building Loads. Values, in kBtu, are reported for heating and cooling. Heating and cooling peak loads include duct losses.

7. Annual Component Building Loads. Component loads represent the estimated contribution of different building components to the annual heating/cooling building loads. The sum of component loads for heating (or cooling) will roughly equal the annual heating (or cooling) building load reported above. Component loads are currently disaggregated as follows:

Component Definition
Roofs Heat transfer through HPXML Roof elements adjacent to conditioned space
Ceilings Heat transfer through HPXML FrameFloor elements (inferred to be ceilings) adjacent to conditioned space
Walls Heat transfer through HPXML Wall elements adjacent to conditioned space
Rim Joists Heat transfer through HPXML RimJoist elements adjacent to conditioned space
Foundation Walls Heat transfer through HPXML FoundationWall elements adjacent to conditioned space
Doors Heat transfer through HPXML Door elements on surfaces adjacent to conditioned space
Windows Heat transfer through HPXML Window elements on surfaces adjacent to conditioned space, including direct/diffuse transmitted solar
Skylights Heat transfer through HPXML Skylight elements on surfaces adjacent to conditioned space, including direct/diffuse transmitted solar
Floors Heat transfer through HPXML FrameFloor elements (inferred to be floors) adjacent to conditioned space
Slabs Heat transfer through HPXML Slab elements adjacent to conditioned space
Internal Mass Heat transfer from additional assumed mass (furniture, interior walls, interior floors between stories) in conditioned space
Infiltration Airflow induced by stack and wind effects
Natural Ventilation Airflow through operable windows
Mechanical Ventilation Airflow (and potentially fan heat gain) from a whole house mechanical ventilation system
Ducts Conduction and leakage losses through supply/return ducts outside conditioned space
Internal Gains Heat gains/losses due to appliances, lighting, plug loads, water heater tank losses, etc. in the conditioned space

See the example ERIRatedHome.csv.

ERI______Home_Hourly.csv

If the --hourly argument is provided when running the workflow, a CSV file of hourly outputs is written for the Reference/Rated Homes (e.g., ERIReferenceHome_Hourly.csv for the Reference home).

Depending on the hourly output types requested, CSV files may include:

  • temperatures: Average space temperatures (in deg-F) for each space modeled (e.g., living space, vented attic, garage, unconditioned basement, crawlspace, etc.).
  • fuels: Energy use for each fuel type (in kBtu for fossil fuels and kWh for electricity).
  • enduses: Energy use for each end use type (in kBtu for fossil fuels and kWh for electricity).
  • loads: Heating and cooling loads (in kBtu) for the building.
  • componentloads: Heating and cooling loads (in kBtu) disaggregated by component (e.g., Walls, Windows, Infiltration, Ducts, etc.).

See the example ERIRatedHome_Hourly.csv.

ERI______Home.xml

A HPXML file is written for each of the homes simulated (e.g., ERIReferenceHome.xml for the Reference home). The file reflects the configuration of the home after applying the ERI 301 ruleset.

See the example ERIRatedHome.xml.

Simulation Files

In addition, raw EnergyPlus simulation input/output files are available for each simulation (e.g., ERIRatedHome, ERIReferenceHome, etc. directories).

Warning

It is highly discouraged for software tools to read the raw EnergyPlus output files. The EnergyPlus input/output files are made available for inspection, but the outputs for certain situations can be misleading if one does not know how the model was created. If there are additional outputs of interest that are not available in our summary output files, please send us a request.

See the example ERIRatedHome directory.