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.

Schema version WUFI-Passive 3.3.x

Data version 48+

Maintainer bldgtyp

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XML Structure Map¶

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

WUFIplusProject
├── DataVersion
├── UnitSystem (0=SI, 1=IP)
├── DaylightSavingTime
├── ProjectData (project name, dates, agents)
├── Graphics3D (3D viewport state — skip)
├── ClimateLocation (weather file, site data)
├── UtilizationPatterns_NonRes (schedule collections)
├── UtilizationPatterns_Ventilation (ventilation schedule collections)
├── Zones
│   └── Zone
│       ├── Name, Volume, FloorArea
│       ├── Components (opaque + aperture surfaces)
│       │   └── Component
│       │       ├── IdentNr, Name, Type (1=opaque, 2=aperture)
│       │       ├── IdentNrAssembly (links to Assembly)
│       │       ├── IdentNrWindowType (links to WindowType, apertures only)
│       │       ├── DepthWindowReveal (apertures only)
│       │       └── DefaultCorrectionShadingMonth (apertures only)
│       ├── Rooms (ventilation spaces)
│       │   └── Room
│       │       ├── Name (matches ventilation device name)
│       │       ├── DesignVolumeFlowRateSupply [m³/h]
│       │       └── DesignVolumeFlowRateExhaust [m³/h]
│       ├── ThermalBridges
│       │   └── ThermalBridge
│       │       ├── Name, PsiValue [W/mK], Length [m]
│       │       └── Type
│       ├── InternalGainsData
│       └── GroundFloor / Foundation data
├── PassivehouseData
│   ├── PH_CertificateCriteria
│   ├── AnnualHeatingDemand [kWh/m²a]
│   ├── AnnualCoolingDemand [kWh/m²a]
│   ├── PeakHeatingLoad [W/m²]
│   ├── PeakCoolingLoad [W/m²]
│   ├── PH_Buildings
│   │   └── PH_Building (building data, airtightness, occupancy)
│   └── UseWUFIMeanMonthShading (true/false)
├── HVAC
│   └── Systems
│       └── System
│           ├── Name, Type, IdentNr
│           ├── ZonesCoverage
│           ├── Devices
│           │   └── Device
│           │       ├── Name, IdentNr
│           │       ├── SystemType (1=ventilation, 2=heating, 5=HP, 10=PV)
│           │       ├── TypeDevice
│           │       ├── UsedFor_Heating/DHW/Cooling/Ventilation
│           │       ├── HeatRecovery (ventilation devices)
│           │       ├── MoistureRecovery (ventilation devices)
│           │       └── PH_Parameters
│           │           ├── ElectricEfficiency [Wh/m³] (ventilation)
│           │           ├── HumidityRecoveryEfficiency (ventilation)
│           │           ├── Quantity (ventilation)
│           │           ├── RatedCOP1, RatedCOP2 (heat pumps)
│           │           ├── AnnualCOP (DHW heat pumps)
│           │           ├── HPWH_EF (DHW heat pumps)
│           │           ├── ArraySizePV [kW] (PV)
│           │           └── PhotovoltaicRenewableEnergy [kWh/yr] (PV)
│           └── PHDistribution
│               ├── DistributionDHW
│               │   └── Truncs > Trunc > Branches > Branch > Twigs
│               │       (piping lengths, materials, diameters)
│               └── DistributionVentilation
│                   └── Ducts
│                       └── Duct
│                           ├── Name
│                           ├── DuctLength [m]
│                           ├── InsulationThickness [mm]
│                           ├── ThermalConductivity [W/mK]
│                           ├── DuctType (1=supply, 2=extract)
│                           ├── DuctShape (1=round, 2=rectangular)
│                           └── AssignedVentUnits
├── Assemblies
│   └── Assembly
│       ├── Name, IdentNr
│       ├── Order_Layers (2=outside-to-inside)
│       └── Layers
│           └── Layer
│               ├── Thickness [m]
│               └── Material
│                   ├── Name, ThermalConductivity [W/mK]
│                   ├── BulkDensity [kg/m³]
│                   └── HeatCapacity [J/kgK]
└── WindowTypes
    └── WindowType
        ├── Name, IdentNr
        ├── FrameFactor (glass fraction, 0-1)
        ├── U_Value [W/m²K] (overall)
        ├── U_Value_Glazing [W/m²K]
        ├── g_Value / SHGC_Hemispherical
        ├── Frame_Width_{Left,Right,Top,Bottom} [m]
        ├── Frame_U_{Left,Right,Top,Bottom} [W/m²K]
        ├── Frame_Psi_{Left,Right,Top,Bottom} [W/mK]
        └── Glazing_Psi_{Left,Right,Top,Bottom} [W/mK]

Device Type Identification¶

SystemType	TypeDevice	What it is
1	1	Mechanical ventilation (ERV/HRV/NERV)
2	2	Direct electric or fossil heater
5	5	Heat pump (heating, cooling, or DHW)
10	10	Photovoltaic / renewable

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

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

Section	Typical line range	Typical size
Zone Components (geometry)	1,000–55,000	50,000+ lines
Zone Rooms (ventilation spaces)	55,000–58,000	2,000–5,000 lines
Thermal Bridges	72,000–73,000	~200 lines
PassivehouseData	73,000–73,130	~130 lines
HVAC Devices	73,130–73,950	~800 lines
DHW Piping	73,950–74,450	~500 lines
Ducts	74,450–75,300	~900 lines
Assemblies	75,600–76,400	~800 lines
WindowTypes	76,400–78,200	~1,800 lines

Quick Lookup Table¶

You want to find...	Look in...
Ventilation units (ERV/HRV/NERV)	`HVAC > Systems > System > Devices` (TypeDevice=1)
Heat pumps, heaters	`HVAC > Systems > System > Devices` (TypeDevice=2 or 5)
DHW water heaters	`HVAC > Systems > System > Devices` (UsedFor_DHW=true)
PV / renewables	`HVAC > Systems > System > Devices` (SystemType=10)
Ducts	`HVAC > Systems > System > PHDistribution > DistributionVentilation > Ducts`
DHW piping	`HVAC > Systems > System > PHDistribution > DistributionDHW > Truncs`
Thermal bridges	`Zones > Zone > ThermalBridges`
Window types (thermal properties)	`WindowTypes > WindowType` (near end of file)
Window components (shading, reveals)	`Zones > Zone > Components > Component` (Type=2)
Opaque assemblies	`Assemblies > Assembly` (near end of file)
Certification targets	`PassivehouseData > AnnualHeatingDemand`, etc.
Space ventilation airflows	`Zones > Zone > Rooms > Room`
Climate / location	`ClimateLocation` or `ProjectData` section

Field Dictionary¶

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

Ventilation Devices¶

WUFI UI Label	XML Element	XML Location	Units in XML
Heat recovery efficiency / SRE	`<HeatRecovery>`	Device	fraction (0–1)
Moisture recovery efficiency	`<MoistureRecovery>`	Device	fraction (0–1)
Humidity recovery efficiency	`<HumidityRecoveryEfficiency>`	Device > PH_Parameters	fraction (0–1)
Electric efficiency	`<ElectricEfficiency>`	Device > PH_Parameters	Wh/m³
Quantity	`<Quantity>`	Device > PH_Parameters	count
Frost protection required	`<DefrostRequired>`	Device > PH_Parameters	boolean
Temperature below which defrost is used	`<TemperatureBelowDefrostUsed>`	Device > PH_Parameters	°C
No summer bypass	`<NoSummerBypass>`	Device > PH_Parameters	boolean
In conditioned space	`<InConditionedSpace>`	Device > PH_Parameters	boolean

Heat Pumps¶

WUFI UI Label	XML Element	XML Location	Units in XML
COP at test point 1	`<RatedCOP1>`	Device > PH_Parameters	dimensionless
COP at test point 2	`<RatedCOP2>`	Device > PH_Parameters	dimensionless
Ambient temp at test point 1	`<AmbientTemperature1>`	Device > PH_Parameters	°C
Ambient temp at test point 2	`<AmbientTemperature2>`	Device > PH_Parameters	°C
Annual COP (DHW)	`<AnnualCOP>`	Device > PH_Parameters	dimensionless
HPWH Energy Factor	`<HPWH_EF>`	Device > PH_Parameters	dimensionless

PV / Renewables¶

WUFI UI Label	XML Element	XML Location	Units in XML
Array size	`<ArraySizePV>`	Device > PH_Parameters	kW
Annual PV energy	`<PhotovoltaicRenewableEnergy>`	Device > PH_Parameters	kWh/yr
On-site utilization	`<OnsiteUtilization>`	Device > PH_Parameters	fraction (0–1)

Ducts¶

WUFI UI Label	XML Element	XML Location	Units in XML
Duct length	`<DuctLength>`	Duct	m
Insulation thickness	`<InsulationThickness>`	Duct	mm
Thermal conductivity of insulation	`<ThermalConductivity>`	Duct	W/mK
Duct diameter	`<DuctDiameter>`	Duct	mm
Duct shape (round/rectangular)	`<DuctShape>`	Duct	1=round, 2=rect
Duct type (supply/extract)	`<DuctType>`	Duct	1=supply, 2=extract
Reflective insulation	`<IsReflective>`	Duct	boolean
Rectangular height	`<DuctShapeHeight>`	Duct	mm
Rectangular width	`<DuctShapeWidth>`	Duct	mm

Windows — WindowType Definition¶

WUFI UI Label	XML Element	XML Location	Units in XML
Frame factor (glass fraction)	`<FrameFactor>`	WindowType	fraction (0–1)
Window U-value (overall)	`<U_Value>`	WindowType	W/m²K
Glazing U-value	`<U_Value_Glazing>`	WindowType	W/m²K
g-value / SHGC	`<g_Value>` or `<SHGC_Hemispherical>`	WindowType	fraction (0–1)
Frame width (per edge)	`<Frame_Width_{Left,Right,Top,Bottom}>`	WindowType	m
Frame U-value (per edge)	`<Frame_U_{Left,Right,Top,Bottom}>`	WindowType	W/m²K
Frame psi-install (per edge)	`<Frame_Psi_{Left,Right,Top,Bottom}>`	WindowType	W/mK
Glazing psi-spacer (per edge)	`<Glazing_Psi_{Left,Right,Top,Bottom}>`	WindowType	W/mK

Windows — Component / Aperture Shading¶

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

WUFI UI Label	XML Element	XML Location	Units in XML
Depth of window reveal	`<DepthWindowReveal>`	Component (Type=2)	m
Distance from glazing edge to reveal	`<DistanceDaylightOpeningToReveal>`	Component (Type=2)	m
Default correction factor (mean month shading)	`<DefaultCorrectionShadingMonth>`	Component (Type=2)	fraction (0–1)
Solar protection device assignment	`<IdentNrSolarProtection>`	Component (Type=2)	ID ref (-1=none)
Overhang assignment	`<IdentNrOverhang>`	Component (Type=2)	ID ref (-1=none)
Window type assignment	`<IdentNrWindowType>`	Component (Type=2)	ID ref

Shading factors are multiplicative

WUFI applies shading from reveal geometry, overhang, solar protection, and the Default correction factor as separate multiplicative factors. The DefaultCorrectionShadingMonth should contain only its intended correction — WUFI independently computes reveal-depth shading from DepthWindowReveal. What this field represents varies by project; always check the project's methodology documentation.

Thermal Bridges¶

WUFI UI Label	XML Element	XML Location	Units in XML
Psi value	`<PsiValue>`	ThermalBridge	W/mK
Length	`<Length>`	ThermalBridge	m
Type	`<Type>`	ThermalBridge	enum

Assemblies¶

WUFI UI Label	XML Element	XML Location	Units in XML
Layer order	`<Order_Layers>`	Assembly	2=outside-to-inside
Layer thickness	`<Thickness>`	Layer	m
Material thermal conductivity	`<ThermalConductivity>`	Material	W/mK
Material density	`<BulkDensity>`	Material	kg/m³
Material heat capacity	`<HeatCapacity>`	Material	J/kgK

Certification / PassivehouseData¶

WUFI UI Label	XML Element	XML Location	Units in XML
Annual heating demand target	`<AnnualHeatingDemand>`	PassivehouseData	kWh/m²a
Annual cooling demand target	`<AnnualCoolingDemand>`	PassivehouseData	kWh/m²a
Peak heating load target	`<PeakHeatingLoad>`	PassivehouseData	W/m²
Peak cooling load target	`<PeakCoolingLoad>`	PassivehouseData	W/m²
Certification criteria selection	`<PH_CertificateCriteria>`	PassivehouseData	enum
Target data selection	`<PH_SelectionTargetData>`	PassivehouseData	enum (2=user)
Airtightness (n50 or ACH)	`<EnvelopeAirtightnessCoefficient>`	PH_Building	1/h
Number of units	`<NumberUnits>`	PH_Building	count
Number of stories	`<CountStories>`	PH_Building	count

Ventilation Spaces (Rooms)¶

WUFI UI Label	XML Element	XML Location	Units in XML
Room/space name	`<Name>`	Room	text
Floor area	`<AreaRoom>`	Room	m²
Clear height	`<ClearRoomHeight>`	Room	m
Design supply airflow	`<DesignVolumeFlowRateSupply>`	Room	m³/h
Design exhaust airflow	`<DesignVolumeFlowRateExhaust>`	Room	m³/h
Ventilation unit assignment	`<IdentNrVentilationUnit>`	Room	ID ref

Unit Conversions¶

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

Ventilation¶

From (IP)	To (SI/XML)	Factor	Notes
CFM	m³/h	× 1.69901	`CFM × 1.69901 = m³/h`
W/cfm	Wh/m³	÷ 1.69901	`(W/cfm) / 1.69901 = Wh/m³`

Thermal Performance¶

From (IP)	To (SI/XML)	Factor
Btu/hr-ft²-F	W/m²K	× 5.6783
W/m²K	Btu/hr-ft²-F	× 0.17611
Btu/hr-ft-F	W/mK (linear, psi)	× 1.7307
W/mK	Btu/hr-ft-F (linear, psi)	× 0.57782

Energy Demand / Load¶

From (IP)	To (SI/XML)	Factor
kBtu/ft²·yr	kWh/m²·yr	× 3.1546
kWh/m²·yr	kBtu/ft²·yr	× 0.31700
Btu/hr·ft²	W/m²	× 3.1546
W/m²	Btu/hr·ft²	× 0.31700

Length / Thickness¶

From (IP)	To (SI/XML)	Factor
inches	meters	× 0.0254
inches	millimeters	× 25.4
feet	meters	× 0.3048

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¶

From (IP)	To (SI/XML)	Formula
R/inch (hr-ft²-F/Btu-in)	W/mK	`k = 0.14423 / (R_per_inch)`
W/mK	R/inch	`R_per_inch = 0.14423 / k`

Temperature¶

From (IP)	To (SI/XML)	Formula
°F	°C	`(°F - 32) / 1.8`
ΔF	ΔC	`ΔF / 1.8`

Area / Volume¶

From (IP)	To (SI/XML)	Factor
ft²	m²	× 0.09290
ft³	m³	× 0.02832

Common Verification Patterns¶

ERV heat recovery: <HeatRecovery>0.857</HeatRecovery> — dimensionless fraction. Compare directly against datasheet SRE/ATRE.
ERV electric efficiency: <ElectricEfficiency>0.3337</ElectricEfficiency> (Wh/m³) → 0.3337 × 1.69901 = 0.567 W/cfm
Duct insulation: <InsulationThickness>47.625</InsulationThickness> (mm) = 1.875". <ThermalConductivity>0.02219</ThermalConductivity> → R/inch = 0.14423/0.02219 = 6.5
Certification target: <AnnualHeatingDemand>11.357</AnnualHeatingDemand> (kWh/m²) → 11.357 × 0.31700 = 3.60 kBtu/ft²
Thermal bridge psi: <PsiValue>0.4344</PsiValue> (W/mK) → 0.4344 / 1.7307 = 0.251 Btu/hr-ft-F

Key Gotchas¶

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 ≈ 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.