WUFI-Passive XML Schema Reference

WUFI-Passive XML files are the primary data exchange format for Passive House energy models. They can be 30,000-100,000+ lines and contain the complete building model: geometry, constructions, windows, HVAC, DHW, renewables, and certification parameters.

XML Structure Map

Format version 3.x, Data Version 48+. Section order is consistent across projects; line numbers vary by project size.

Top-Level Overview

The XML has two structural tiers: root-level sections shared across all variants, and per-variant data containing the building model. Assemblies, WindowTypes, and SolarProtectionTypes are root-level type libraries — components inside each variant reference them by IdentNr.

Document Root

Inside a Variant

Each Variant contains five branches. Note that Components and Zones are siblings under Building, not nested.

Detailed Element Trees

Root & Project Metadata

WUFIplusProject
├── DataVersion (e.g. 48)
├── UnitSystem (0=SI, 1=IP)
├── ProgramVersion (e.g. "3.2.0.1")
├── Scope
├── DimensionsVisualizedGeometry
├── ProjectData
│   ├── Year_Construction
│   ├── OwnerIsClient
│   ├── Date_Project (Year, Month, Day, Hour, Minutes)
│   ├── WhiteBackgroundPictureBuilding
│   ├── Customer_{Name,Street,Locality,PostalCode,Tel,Email}
│   ├── Building_{Name,Street,Locality,PostalCode}
│   ├── Owner_{Name,Street,Locality,PostalCode}
│   └── Responsible_{Name,Street,Locality,PostalCode,Tel,LicenseNr,Email}
├── UtilisationPatternsVentilation (ventilation schedule collection)
├── UtilizationPatternsPH (occupancy schedule collection)
├── Variants (contains one or more Variant — see below)
├── Assemblies (opaque construction types — see below)
├── WindowTypes (window construction types — see below)
└── SolarProtectionTypes (shading device types)

Schedules

UtilisationPatternsVentilation
└── UtilizationPatternVent
    ├── Name, IdentNr
    ├── OperatingDays (days/week), OperatingWeeks (weeks/year)
    ├── Maximum_DOS, Maximum_PDF (high-speed period: hours, speed fraction)
    ├── Standard_DOS, Standard_PDF
    ├── Basic_DOS, Basic_PDF
    └── Minimum_DOS, Minimum_PDF

UtilizationPatternsPH
└── UtilizationPattern
    ├── IdentNr, Name
    ├── HeightUtilizationLevel
    ├── BeginUtilization, EndUtilization (hours)
    ├── AnnualUtilizationDays
    ├── IlluminationLevel [lux]
    ├── RelativeAbsenteeism
    └── PartUseFactorPeriodForLighting

Variant

Variant
├── IdentNr, Name, Remarks
├── Graphics_3D (geometry data)
│   ├── Vertices > Vertix (IdentNr, X, Y, Z)
│   └── Polygons > Polygon (IdentNr, NormalVector{X,Y,Z}, IdentNrPoints, IdentNrPolygonsInside)
├── Building
│   ├── Components (ALL opaque + aperture + shade surfaces for the building)
│   │   └── Component (see Component details below)
│   └── Zones (zone definitions)
│       └── Zone (see Zone details below)
├── ClimateLocation (see ClimateLocation below)
├── PassivehouseData (see PassivehouseData below)
└── HVAC (see HVAC below)

Components (under Building)

Component (opaque — Type=1)
├── IdentNr, Name, Visual
├── Type (1=opaque)
├── IdentNrColorI, IdentNrColorE (interior/exterior color IDs)
├── InnerAttachment (1=zone interior, -1=not attached)
├── OuterAttachment (-1=exterior/ambient, -2=ground)
├── IdentNr_ComponentInnerSurface (-1 or zone surface ID)
├── IdentNrAssembly (links to Assembly)
├── IdentNrWindowType (-1 for opaque)
└── IdentNrPolygons (list of polygon IDs)

Component (aperture — Type=2)
├── (same base fields as opaque, but IdentNrAssembly=-1)
├── IdentNrWindowType (links to WindowType)
├── DepthWindowReveal [m]
├── DistanceDaylightOpeningToReveal [m]
├── IdentNrSolarProtection (ID ref, -1=none)
├── IdentNrOverhang (ID ref, -1=none)
└── DefaultCorrectionShadingMonth (fraction 0-1)

Component (shade surface — Type=1, special case)
├── Type=1 (same as opaque)
├── InnerAttachment=-1, OuterAttachment=-1 (neither attached)
├── IdentNrAssembly=-1 (no assembly)
└── IdentNrWindowType=-1

Zones

Zone
├── Name, IdentNr
├── KindZone (1=conditioned, etc.)
├── KindAttachedZone
├── TemperatureReductionFactorUserDefined
├── RoomsVentilation (ventilation spaces)
│   └── Room
│       ├── Name, Type (room type code, 99=user-defined)
│       ├── IdentNrUtilizationPatternVent (links to ventilation schedule)
│       ├── IdentNrVentilationUnit (links to ventilation device)
│       ├── Quantity
│       ├── AreaRoom [m²]
│       ├── ClearRoomHeight [m]
│       ├── DesignVolumeFlowRateSupply [m³/h]
│       └── DesignVolumeFlowRateExhaust [m³/h]
├── LoadsPersonsPH (occupancy loads per space)
│   └── LoadPerson
│       ├── Name, IdentNrUtilizationPattern
│       ├── ChoiceActivityPersons
│       ├── NumberOccupants
│       └── FloorAreaUtilizationZone [m²]
├── LoadsLightingsPH (lighting loads per space)
│   └── LoadsLighting
│       ├── Name, RoomCategory
│       ├── InstalledLightingPower [W/m²]
│       └── LightingFullLoadHours [hrs/yr]
├── GrossVolume_Selection, GrossVolume [m³]
├── NetVolume_Selection, NetVolume [m³]
├── FloorArea_Selection, FloorArea [m²] (iCFA)
├── ClearanceHeight_Selection, ClearanceHeight [m]
├── SpecificHeatCapacity_Selection, SpecificHeatCapacity [Wh/m²K]
├── IdentNrPH_Building
├── OccupantQuantityUserDef
├── NumberBedrooms
├── HomeDevice (electrical equipment — appliances, lighting, MEL)
│   └── Device
│       ├── Comment, ReferenceQuantity, Quantity
│       ├── InConditionedSpace
│       ├── ReferenceEnergyDemandNorm, EnergyDemandNorm
│       ├── EnergyDemandNormUse, CEF_CombinedEnergyFactor
│       ├── IHG_UtilizationFactor
│       ├── Type (1=dishwasher, 2=clothes washer, 3=dryer, 7=cooktop,
│       │         13=MEL, 14=interior lighting, 15=exterior lighting, etc.)
│       └── (type-specific fields: Connection, CookingWith, FractionHightEfficiency, etc.)
├── ExhaustVents (exhaust-only ventilation devices)
│   └── ExhaustVent
│       ├── Name, Type (1=dryer, 2=kitchen hood)
│       ├── ExhaustVolumeFlowRate [m³/h]
│       └── RunTimePerYear [minutes]
├── ThermalBridges
│   └── ThermalBridge
│       ├── Name, Type (negative group number)
│       ├── Length [m], PsiValue [W/mK]
│       └── IdentNrOptionalClimate
├── SummerNaturalVentilationDay [1/hr]
└── SummerNaturalVentilationNight [1/hr]

ClimateLocation

ClimateLocation
├── Selection
├── Latitude_DB, Longitude_DB, HeightNN_DB, dUTC_DB
├── Albedo, GroundReflShort, GroundReflLong, GroundEmission
├── CloudIndex, CO2concenration, Unit_CO2concentration
└── PH_ClimateLocation
    ├── Selection
    ├── DailyTemperatureSwingSummer, AverageWindSpeed
    ├── Latitude, Longitude, HeightNNWeatherStation, dUTC
    ├── HeightNNBuilding, ClimateZone
    ├── GroundThermalConductivity, GroundHeatCapacitiy, GroundDensity
    ├── DepthGroundwater, FlowRateGroundwater
    ├── TemperatureMonthly (12 Items)
    ├── DewPointTemperatureMonthly (12 Items)
    ├── SkyTemperatureMonthly (12 Items)
    ├── {North,East,South,West,Global}SolarRadiationMonthly (12 Items each)
    ├── Peak Heating 1: Temperature, {N,E,S,W,Global}SolarRadiation
    ├── Peak Heating 2: Temperature, {N,E,S,W,Global}SolarRadiation
    ├── Peak Cooling 1: Temperature, {N,E,S,W,Global}SolarRadiation
    ├── Peak Cooling 2: Temperature, {N,E,S,W,Global}SolarRadiation
    ├── SelectionPECO2Factor
    ├── PEFactorsUserDef (16 fuel-type PE factors, kWh/kWh)
    └── CO2FactorsUserDef (16 fuel-type CO2 factors, g/kWh)

PassivehouseData

PassivehouseData
├── PH_CertificateCriteria (certification program enum)
├── PH_SelectionTargetData (2=user-defined targets)
├── AnnualHeatingDemand [kWh/m²a]
├── AnnualCoolingDemand [kWh/m²a]
├── PeakHeatingLoad [W/m²]
├── PeakCoolingLoad [W/m²]
├── PH_Buildings
│   └── PH_Building
│       ├── IdentNr
│       ├── BuildingCategory (1=residential, etc.)
│       ├── OccupancyTypeResidential
│       ├── BuildingStatus (1=new, 2=retrofit)
│       ├── BuildingType
│       ├── OccupancySettingMethod (2=user-defined)
│       ├── NumberUnits, CountStories
│       ├── EnvelopeAirtightnessCoefficient [1/h] (q50 or n50)
│       ├── SummerHRVHumidityRecovery (bypass mode)
│       ├── BuildingWindExposure
│       ├── FoundationInterfaces
│       │   └── FoundationInterface
│       │       ├── Name
│       │       ├── SettingFloorSlabType (6=user-defined)
│       │       ├── FloorSlabType (3=slab-on-grade, etc.)
│       │       └── (type-specific fields: areas, perimeters, U-values,
│       │            perimeter insulation properties)
│       ├── InternalGainsAdditionalData
│       │   ├── EvaporationHeatPerPerson [W]
│       │   ├── HeatLossFluschingWC, QuantityWCs
│       │   └── RoomCategory, UseDefaultValuesSchool
│       ├── MechanicalRoomTemperature [°C]
│       ├── IndoorTemperature [°C] (heating setpoint)
│       ├── OverheatingTemperatureThreshold [°C] (cooling setpoint)
│       └── NonCombustibleMaterials (boolean)
└── UseWUFIMeanMonthShading (true/false)

HVAC

HVAC
└── Systems
    └── System
        ├── Name, Type, IdentNr
        ├── ZonesCoverage
        │   └── ZoneCoverage
        │       ├── IdentNrZone
        │       └── Coverage{Heating,Cooling,Ventilation,Humidification,Dehumidification}
        ├── Devices
        │   └── Device
        │       ├── Name, IdentNr
        │       ├── SystemType, TypeDevice (see Device Type table)
        │       ├── UsedFor_{Heating,DHW,Cooling,Ventilation,Humidification,Dehumidification}
        │       ├── (ventilation devices only:)
        │       │   ├── UseOptionalClimate, IdentNr_OptionalClimate
        │       │   ├── HeatRecovery, MoistureRecovery
        │       │   └── PH_Parameters (Quantity, HumidityRecoveryEfficiency,
        │       │       ElectricEfficiency, DefrostRequired, FrostProtection,
        │       │       TemperatureBelowDefrostUsed, InConditionedSpace, NoSummerBypass)
        │       ├── (heat pump devices only:)
        │       │   ├── PH_Parameters (AuxiliaryEnergy, AuxiliaryEnergyDHW,
        │       │   │   InConditionedSpace, HPType,
        │       │   │   RatedCOP1/2, AmbientTemperature1/2 — monthly type,
        │       │   │   AnnualCOP, HPWH_EF — annual/hot-water type)
        │       │   ├── DHW_Parameters (CoverageWithinSystem, Unit, Selection)
        │       │   ├── Heating_Parameters (CoverageWithinSystem, Unit, Selection)
        │       │   └── Cooling_Parameters (CoverageWithinSystem, Unit, Selection)
        │       ├── (water storage devices only:)
        │       │   └── PH_Parameters (SolarThermalStorageCapacity,
        │       │       StorageLossesStandby, InputOption, QauntityWS,
        │       │       TankRoomTemp, TypicalStorageWaterTemperature, etc.)
        │       └── (PV devices only:)
        │           └── PH_Parameters (SelectionLocation, ArraySizePV,
        │               PhotovoltaicRenewableEnergy, OnsiteUtilization, etc.)
        └── PHDistribution
            ├── DistributionDHW
            │   ├── CalculationMethodIndividualPipes
            │   ├── DemandRecirculation, SelectionhotWaterFixtureEff
            │   ├── NumberOfBathrooms, AllPipesAreInsulated
            │   ├── SelectionUnitsOrFloors, PipeMaterialSimplifiedMethod
            │   ├── PipeDiameterSimplifiedMethod
            │   ├── TemperatureRoom_WR, DesignFlowTemperature_WR
            │   ├── DailyRunningHoursCirculation_WR
            │   ├── LengthCirculationPipes_WR, HeatLossCoefficient_WR
            │   ├── LengthIndividualPipes_WR, ExteriorPipeDiameter_WR
            │   └── Truncs > Trunc
            │       ├── Name, IdentNr, PipingLength, PipeMaterial, PipingDiameter
            │       ├── CountUnitsOrFloors, DemandRecirculation
            │       └── Branches > Branch
            │           ├── Name, IdentNr, PipingLength, PipeMaterial, PipingDiameter
            │           └── Twigs > Twig
            │               └── Name, IdentNr, PipingLength, PipeMaterial, PipingDiameter
            ├── DistributionCooling (if cooling devices present)
            │   ├── CoolingViaVentilationAir, CoolingViaRecirculation
            │   ├── Dehumidification, PanelCooling
            │   ├── (recirculation:) RecirculatingAirOnOff, MaxRecirculationAirCoolingPower,
            │   │   MinTempCoolingCoilRecirculatingAir, RecirculationCoolingCOP,
            │   │   RecirculationAirVolume, ControlledRecirculationVolumeFlow
            │   └── (dehumidification:) DehumdificationCOP, SEER, EER
            ├── DistributionVentilation
            │   └── Duct
            │       ├── Name, IdentNr
            │       ├── DuctDiameter [mm], DuctShapeHeight [mm], DuctShapeWidth [mm]
            │       ├── DuctLength [m]
            │       ├── InsulationThickness [mm], ThermalConductivity [W/mK]
            │       ├── Quantity
            │       ├── DuctType (1=supply, 2=extract)
            │       ├── DuctShape (1=round, 2=rectangular)
            │       ├── IsReflective
            │       └── AssignedVentUnits > IdentNrVentUnit
            ├── UseDefaultValues, DeviceInConditionedSpace
            └── SupportiveDevices
                └── SupportiveDevice
                    ├── Name, Type, Quantity
                    ├── InConditionedSpace
                    ├── NormEnergyDemand [W]
                    └── PeriodOperation [khrs]

Assemblies

Assemblies
└── Assembly
    ├── IdentNr, Name
    ├── Order_Layers (2=outside-to-inside)
    ├── Grid_Kind (2=standard)
    ├── Layers
    │   └── Layer
    │       ├── Thickness [m]
    │       ├── Material
    │       │   ├── Name, ThermalConductivity [W/mK]
    │       │   ├── BulkDensity [kg/m³], Porosity
    │       │   ├── HeatCapacity [J/kgK]
    │       │   ├── WaterVaporResistance, ReferenceWaterContent
    │       │   └── Color (Alpha, Red, Green, Blue)
    │       ├── ExchangeDivisionHorizontal (column widths for inhomogeneous layers)
    │       ├── ExchangeDivisionVertical (row heights for inhomogeneous layers)
    │       └── ExchangeMaterialIdentNrs (material IDs for divided cells)
    └── ExchangeMaterials (alternate materials for inhomogeneous layers)
        └── ExchangeMaterial
            ├── IdentNr, Name
            ├── ThermalConductivity [W/mK], BulkDensity [kg/m³]
            ├── HeatCapacity [J/kgK]
            └── Color (Alpha, Red, Green, Blue)

WindowTypes

WindowTypes
└── WindowType
    ├── IdentNr, Name
    ├── Uw_Detailed (true/false — use detailed U-value calculation)
    ├── GlazingFrameDetailed (true/false — use per-edge frame data)
    ├── FrameFactor (glass fraction, 0-1)
    ├── U_Value [W/m²K] (overall window U-value)
    ├── U_Value_Glazing [W/m²K]
    ├── MeanEmissivity (glazing emissivity)
    ├── g_Value / SHGC_Hemispherical (solar heat gain)
    ├── U_Value_Frame [W/m²K] (overall frame U-value)
    ├── Frame_Width_{Left,Right,Top,Bottom} [m]
    ├── Frame_Psi_{Left,Right,Top,Bottom} [W/mK] (install psi)
    ├── Frame_U_{Left,Right,Top,Bottom} [W/m²K]
    └── Glazing_Psi_{Left,Right,Top,Bottom} [W/mK] (spacer psi)

SolarProtectionTypes

SolarProtectionTypes
└── SolarProtectionType
    ├── IdentNr, Name
    ├── OperationMode
    ├── MaxRedFactorRadiation (reduction factor)
    ├── ExternalEmissivity, EquivalentAbsorptivity
    ├── ThermalResistanceSupplement, ThermalResistanceCavity
    ├── RadiationLimitValue
    └── ExcludeWeekends

Device Type Identification

The UsedFor_* boolean fields further distinguish purpose (heating, DHW, cooling, ventilation, humidification, dehumidification).

Heat pump HPType sub-types (in PH_Parameters):

Section Size Estimates (typical large multifamily, ~78,000 lines)

Navigating Efficiently

For files over 50,000 lines:

1. grep first — grep -n "SearchTerm" model.xml to find line numbers
2. Read targeted ranges — once you know a device is at line 73200, read lines 73190-73260 to get the full element
3. Use XML element names — searching for <HeatRecovery> or <InsulationThickness> is often faster than searching for device names
4. Assemblies and WindowTypes are near the end — typically the last 2,000-3,000 lines of the file
5. Devices are clustered — all devices for a system are sequential, so once you find one, the others are nearby

Quick Lookup Table

Field Dictionary

Maps WUFI-Passive UI labels to their XML element names.

Ventilation Devices

Heat Pumps

Hot Water Storage Tanks

PV / Renewables

Ducts

Windows — WindowType Definition

Windows — Component / Aperture Shading

These fields live on the aperture Component entries in the Building, NOT on the WindowType.

Thermal Bridges

Assemblies

Certification / PassivehouseData

Ventilation Spaces (Rooms)

Exhaust Ventilators

Supportive Devices

Unit Conversions

WUFI-Passive XML stores all values in SI units regardless of the project’s display unit system.

Ventilation

The factor 1.69901 appears in both airflow and electric efficiency conversions because both involve cubic feet per minute to cubic meters per hour. To verify a W/cfm value, multiply the XML Wh/m³ value by 1.69901 and see if you recover the expected W/cfm.

Thermal Performance

Energy Demand / Load

The demand (kBtu/ft²-yr to kWh/m²-yr) and load (Btu/hr-ft² to W/m²) conversions use the same factor because they are dimensionally equivalent for the area-normalized quantities WUFI uses.

Length / Thickness

Common duct insulation thicknesses: 1” = 25.4 mm, 1.5” = 38.1 mm, 1.875” = 47.625 mm, 2” = 50.8 mm.

R-value / Conductivity

Example: Composite duct insulation at R-6.5/inch -> k = 0.14423 / 6.5 = 0.02219 W/mK.

Temperature

Area / Volume

Common Verification Patterns

ERV/HRV heat recovery: XML: <HeatRecovery>0.857</HeatRecovery> — dimensionless fraction (0-1). No conversion needed. Compare directly against datasheet SRE/ATRE values.

ERV/HRV electric efficiency: XML: <ElectricEfficiency>0.333723600693</ElectricEfficiency> (Wh/m³). To verify against a W/cfm spec: 0.3337 x 1.69901 = 0.567 W/cfm.

Duct insulation: XML: <InsulationThickness>47.625</InsulationThickness> (mm) and <ThermalConductivity>0.02219</ThermalConductivity> (W/mK). To verify: 47.625 mm = 1.875 inches. k = 0.02219 -> R/inch = 0.14423 / 0.02219 = 6.5.

Certification target: XML: <AnnualHeatingDemand>11.357</AnnualHeatingDemand> (kWh/m²). To verify against kBtu/ft²: 11.357 x 0.31700 = 3.60 kBtu/ft².

Thermal bridge psi: XML: <PsiValue>0.4344</PsiValue> (W/mK). To verify against Btu/hr-ft-F: 0.4344 / 1.7307 = 0.251 Btu/hr-ft-F.

Window reveal depth: XML: <DepthWindowReveal>0.15875</DepthWindowReveal> (m). To verify: 0.15875 / 0.0254 = 6.25 inches.

Key Gotchas

Variants wrapper. Building data, HVAC, PassivehouseData, and ClimateLocation are all nested inside Variants > Variant, NOT at the root level. Only Assemblies, WindowTypes, and SolarProtectionTypes live at the root. An LLM looking for zones or devices must navigate through the Variant first.

Components are siblings of Zones, not children. Both Components and Zones are children of Building. Components hold the geometry and assembly/window-type links; Zones hold rooms, thermal bridges, and electrical equipment. Don’t look for components inside a zone.

RoomsVentilation, not Rooms. The ventilation room list element is <RoomsVentilation>, not <Rooms>. Each child is a <Room>.

UtilisationPatternsVentilation spelling. The ventilation schedule list uses British spelling (UtilisationPatterns... with ‘s’), while child elements and the occupancy list use American spelling (UtilizationPattern... with ‘z’). This matches WUFI’s own inconsistency.

FrameFactor vs DefaultCorrectionShadingMonth. FrameFactor on the WindowType is the glass-to-total area ratio for thermal calculation. DefaultCorrectionShadingMonth on the aperture Component (Type=2) is a separate solar correction factor. Don’t confuse them. On some projects, WindowType may have FrameFactor near 1.0 with near-zero frame widths because the U-value was pre-calculated externally.

ElectricEfficiency is in Wh/m³, not W/cfm. Divide by 1.69901 to get W/cfm, or multiply W/cfm by 0.58856 to predict the XML value.

Order_Layers on assemblies matters. Order_Layers=2 means layers are listed outside-to-inside. For floor assemblies over ground, “outside” = ground side.

Airflows are in m³/h, not CFM. Divide by 1.69901 to convert to CFM.

Thermal conductivity for ducts is composite. If duct insulation has multiple layers, the XML stores a single equivalent conductivity.

PsiValue on thermal bridges is in W/mK. Divide by 1.7307 to convert to Btu/hr-ft-F.

InternalGainsAdditionalData and Foundations are under PH_Building. These are nested inside PassivehouseData > PH_Buildings > PH_Building, not under Zone. Don’t look for foundation data at the zone level.

QauntityWS is intentionally misspelled. The hot water tank quantity field is <QauntityWS>, matching WUFI’s own XML naming. Do not “correct” this to QuantityWS.

Shade surfaces look like opaque components. Shade/overhang surfaces appear as Components with Type=1 (opaque) but with InnerAttachment=-1 and OuterAttachment=-1, and IdentNrAssembly=-1. They have geometry but no thermal properties.

OuterAttachment values. -1 = exterior (ambient), -2 = ground. This distinguishes above-grade walls from below-grade/ground-contact surfaces.

g_Value and SHGC_Hemispherical are the same value. Both elements are written with the same glass solar heat gain value. Either can be used for verification.