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Single-Family Detached

Consider the highlighted “Single-Family Detached” building footprint with the following high-level URBANopt GeoJSON inputs:

  • 1 story above ground
  • unvented crawlspace foundation
  • vented attic
  • 2 car garage

single_family_detached

An example 3D rendering of the single-family detached building is shown below.

single_family_detached

Note that the footprint of the modeled unit, less the garage, is always rectangular even though the GeoJSON footprint may not be. See Other Assumptions for more information.

The 3D building surfaces stored in HPXML and OSM models represent the area and orientation of ground and exterior exposure of surfaces, but do not represent their position relative to each other. An example geometry rendering for a translated HPXML file is given below.

single_family_detached

Modeling Notes

  • “Single-Family Detached” home models may contain unconditioned non-living spaces that are included as part of the total building area, such as a garage. As a result energy use intensities (EUIs) for homes, often calculated in units of kBtu/sqft/yr, will vary based on the unconditioned floor area if total building area is used for the calculation. Alternatively, conditioned floor area can be used for such calculations.
  • “Single-Family Detached” home models may be heated only, cooled only, or both heated and cooled.
    • Partial Conditioning: heating and cooling may be applied to just a portion of the living space of the home or to the entire living space. Representation of partial conditioning of the living space of a home is accomplished by adding ideal air load system to heat and cool the unconditioned portion of the living area. In this situation, district heating or cooling loads may show up in end uses for the home.
    • Undersized Mechanical System: District heating or cooling loads may also show up in end uses when a designed mechanical system cannot meet the load required to maintain thermostat temperatures. An example would be an evaporative cooling system in a hot humid climate.
    • For both the partially conditioned and undersized examples, it is possible for reporting or post processing to filter out these unintended district heating and cooling loads.
  • It is important to know, that unlike the commercial models that will result in unmet heating or cooling hours, the residential models will not have any unmet heating or cooling hours. To understand how the HVAC system is conditioning for “Single-Family Detached” home models, users should look at district heating and cooling loads.

GeoJSON Schema

The URBANopt GeoJSON schema differentiates between sets of required and optional fields for “Single-Family Detached” residential buildings:

Required fields:

Field Type Enums Notes
floor_area number   Conditioned floor area.
number_of_stories_above_ground integer    
number_of_stories integer   Includes foundations.
number_of_bedrooms integer   Must be > 0.
foundation_type string (1) slab
(2) crawlspace - vented
(3) crawlspace - unvented
(4) basement - unconditioned
(5) basement - conditioned
(6) ambient
 
attic_type string (1) attic - vented
(2) attic - unvented
(3) attic - conditioned
(4) flat roof
Stories > 1 for conditioned attics.

Optional fields:

Field Type Enums Notes
system_type string (1) electric resistance
(2) furnace
(3) boiler
(4) central air conditioner
(5) room air conditioner
(6) evaporative cooler
(7) air-to-air heat pump
(8) mini-split heat pump
(9) ground-to-air-heat-pump
 
heating_system_fuel_type string (1) electricity
(2) natural gas
(3) fuel oil
(4) propane
(5) wood
 
onsite_parking_fraction number (1) No (0)
(2) Yes (1)
 
template string   See Customizable Template

An example “Single-Family Detached” building feature snippet is shown below.

  {
    "type": "Feature",
    "properties": {
      "id": "14",
      "name": "Residential 1",
      "type": "Building",
      "building_type": "Single-Family Detached",
      "floor_area": 3055,
      "footprint_area": 3055,
      "number_of_stories_above_ground": 1,
      "number_of_stories": 1,
      "number_of_bedrooms": 3,
      "foundation_type": "crawlspace - unvented",
      "attic_type": "attic - vented",
      "system_type": "Residential - furnace and central air conditioner",
      "heating_system_fuel_type": "natural gas",
      "onsite_parking_fraction": 1,
      "template": "Residential IECC 2015 - Customizable Template Sep 2020"
    }

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