The code carries this ID and the SHA-256 fingerprints of the Revit model and its IFC export, so a scan can be checked against the files.
At a glance
Areas are read from the Revit model through its IFC export; gross area is from sheet A100. Energy figures are first-pass design estimates for the Passive House specification in this twin.
185.78m²
Gross building area
108.7m²
Heated floor area (excl. garage)
3bed
Bedrooms, 2 bathrooms
Apredicted
EPC band (indicative)
≈16kWh/m²a
Space heating demand (PH limit 15)
0.10W/m²K
External wall U-value (PH)
0.80W/m²K
Window Uw (PH)
7.56kWp
Solar PV, 10 kWh battery
≈90L/p/d
Water use (Part G method)
439
Twin elements
Rooms and fabric
Rooms are the IfcSpace objects in the model, with areas measured from their geometry. Build-ups are the Revit compound layers.
Room schedule
No.
Room
Area
115
Kitchen Dining Living
37.44 m²
110
Garage
31.20 m²
118
Master Bedroom
15.11 m²
112
Corridor
14.82 m²
113
Bedroom 1
10.20 m²
119
Bedroom 2
10.20 m²
116
Bathroom
7.81 m²
111
Utility
5.40 m²
117
Ensuite
4.24 m²
114
Hall
3.51 m²
Total, 10 rooms
139.93 m²
External wall550 mm
Render Material 255-255-25525 mmFEA-Rigid insulation (Flat Roof)250 mmMasonry - Concrete Block250 mmPlasterboard25 mm
AEG L7WBG741R washer; hob, oven tower and extractor hood
Passive House specification
The twin carries a Passive House design layer over the Revit model. Each Revit element shows its as-modelled value and the Passive House target in its record. Targets follow the PHI criteria; certification needs a PHPP model and a blower-door test.
Roof 300 Spanish tiles; no insulation layer modelled
400 mm mineral wool at ceiling, airtight membrane, 50 mm service void
U 0.09
Ground floor and foundation
Grindys floor U 0.113 on strip foundation walls
Insulated raft: 300 mm EPS 150 under 250 mm raft, 150 mm edge upstand, UFH screed
U 0.10
Windows
Windows_Sgl_Plain, Uw 5.562 (family default)
PH-certified triple glazing, Ug 0.53, g 0.50, installed in the insulation line
Uw ≤ 0.80
External doors
Ud 3.69
PH-certified entrance and terrace doors, triple seal
Ud ≤ 0.80
Airtightness
Not specified
Wet plaster and taped membrane, services in void below
n50 ≤ 0.6 h⁻¹
Thermal bridges
Not specified
Raft edge and window junctions detailed thermal-bridge-free
ψ ≤ 0.01 W/mK
Ventilation
None
MVHR in the loft, intake and exhaust via the chimney
≥ 90 % recovery
Heating and hot water
Fondital gas boiler + Toshiba unit
Toshiba Estia heat pump as main source, UFH at low flow temperature; boiler not used
SCOP ≈ 4
Energy performance
Indicative only. The EPC band is a design prediction, not a certificate; it needs a SAP 10.2 assessment by an accredited assessor. Passive House figures are a first-pass hand calculation, to be confirmed in PHPP.
EPC rating (predicted)
A 92+◀ Predicted A
B 81–91
C 69–80
D 55–68
E 39–54
F 21–38
G 1–20
Based on the Passive House fabric, heat pump heating and hot water, 7.56 kWp PV and a 10 kWh battery. With the gas boiler as main heating the band would fall, likely to B.
Space heating demand
≈ 16 kWh/m²a PH limit 15: refine in PHPP
Heating load
≈ 14 W/m² PH limit 10
Heat loss coefficient
≈ 66 W/K (fabric + ventilation)
Airtightness
n50 ≤ 0.6 h⁻¹ (design target)
Heat recovery
≥ 90 %, MVHR in the loft
PV generation
≈ 6,400 kWh/yr if the rear slope faces south; ≈ 3,900 kWh/yr if north
Storage
10 kWh LiFePO4 battery, 6 kW hybrid inverter
Lighting
All LED: 87 × 6 W downlights, external LED, soffit lamps changed to 5 W LED
To reach the space-heating limit: Uw 0.75, wall U 0.09 and 92 % heat recovery together bring the estimate to about 14 kWh/m²a. The bungalow form and the attached garage make compactness the main challenge.
Water efficiency
Building Regulations Part G calculation method with the low-flow fittings now recorded on each sanitary element.
Fitting
Specification
L/person/day
WCs (2)
Dual flush 4 / 2.6 L
13.5
Basin taps
4 L/min aerated
6.3
Bath
155 L to overflow
17.1
Showers (2)
6 L/min with flow limiter
26.2
Kitchen tap
6 L/min
13.0
Washing machine
≈ 6 L/kg
12.6
Dishwasher
Default 1.25 L/place setting
4.5
Total (× 0.91 + 5 L external)
Part G optional requirement 110, standard 125
≈ 90
Building systems
Added in the twin as separate elements with Twin IDs. Open the twin and use Plumbing, Ventilation, Electrical or Energy in the Model panel to see each system.
Water and waste
Hot and cold 15 mm PEX from the 200 L cylinder and mains inlet, through the loft to all 9 fittings; 40–50 mm trapped wastes to the below-slab foul drains
Ventilation
PH-certified MVHR in the loft over the utility; 5 supply valves (bedrooms, living, dining), 4 extracts (kitchen, bathroom, ensuite, utility); 160 mm intake and exhaust up the chimney to louvres on opposite faces
Foundation
Insulated raft under the heated footprint; the garage sits on a separate slab outside the thermal envelope
Solar PV
18 × 420 Wp panels on the rear roof slope, DC cable through the loft to the utility
Inverter and battery
6 kW hybrid inverter and 10 kWh battery on the utility north wall, radial circuit R4
Smart metering
SMETS2 import/export electricity meter, smart water meter in the boundary box, in-home display in the hall
Wi-Fi and controls
3 PoE Wi-Fi access points on Cat6 from the router, home energy hub in the utility, 9 smart UFH room thermostats, MVHR controller
External lighting
Revit soffit downlights over the terrace and porch now on circuit L4 with LED lamps
Element inventory
Every Revit element keeps its Revit element ID and IFC GlobalId, and opens with its full record in the twin. The main roof is one Revit roof split into six faces. A further 231 elements were added in the twin: 147 electrical, 35 utility connections and heating, 16 water and waste, 12 ventilation, 15 smart controls, 5 solar and battery, and the insulated raft.
Furniture34
Walls27
Casework25
Light fittings20
Plumbing fixtures18
Kerbs12
Doors12
Rooms10
Foundation walls10
External surfaces9
Roof faces7
Mechanical equipment6
Windows6
Rainwater goods5
Columns2
Generic models1
Ceilings1
Floors1
Appliances1
Fencing1
Utility connections
Traced from the services sketch of 11 Oct 2026 and added to the twin as separate elements. Routes are indicative. Depths and sizes are typical assumptions until the services are surveyed.
Service
Route
Size
Depth
Foul drainage
Ensuite WC → bathroom WC → inspection chamber IC1 (east of kitchen); kitchen sink → IC1; IC1 → public sewer in the road
110 mm uPVC
0.35–1.70 m
Mains water
Road main → boundary stop tap → up the west side → through the slab to the mains inlet and stopcock in the utility
25 mm MDPE
0.75 m
Electricity
LV mains in the road → up the west side → external meter box → meter tails to the consumer unit in the utility
Service cable in 50 mm duct
0.60 m
Fibre
Network duct in the road → up the east side → through the east wall to the ONT in the living area
32 mm lead-in duct
0.45 m
Rainwater
Four downpipes, the garage apron channel drain and a front drain from the kitchen and porch downpipes, all joining a west-side drain to the road connection
110 mm uPVC
0.45–1.75 m
Underfloor heating
Boiler primaries → 10-port manifold in the utility → nine room circuits in the screed
16 mm PE-RT, 200 mm centres
in screed
Utility room plant: Fondital Antea CTFS 24 boiler, Fondital 200 L cylinder, UFH manifold, mains water inlet and stopcock, consumer unit. The electric meter is in an external box on the west wall beside the Toshiba unit.
Electrical layout
An indicative design added in the twin. Every device and circuit is its own element with a Twin ID, room and circuit. Confirm with the electrical designer to BS 7671 before installation.
Room
Downlights
Sockets
Switches
Kitchen Dining Living
24
11
1 (3-gang)
Corridor
12
2
1
Master Bedroom
9
5
1
Garage
9
3
1
Bedroom 1
6
4
1
Bedroom 2
6
4
1
Bathroom
6
1 shaver
1
Hall
6
1
1
Utility
6
3
1
Ensuite
3
1 shaver
1
Total
87
35
10
Plus 7 external lights on circuit L3. The Revit model adds 20 soffit downlights over the porch and rear terrace.
Downlights
6 W fire-rated LED, 3000 K, ≈ 550 lm, IP65 in bathroom and ensuite
Sockets
13 A double switched at 450 mm; 4 worktop doubles at 1050 mm; shaver units in bathroom and ensuite
Switches
2-way dimmable plates at 1200 mm beside the door
External, front
Wall lanterns either side of the garage door and at the entrance
External, rear
Wall lantern at the master French doors and at the terrace bi-fold
External, sides
Bulkhead beside the west glazed door; wall lantern beside the east glazed door
Circuits
L1, L2 lighting (6 A); L3 external (6 A RCBO); R1, R2 ring finals (32 A RCBO); R3 radial (20 A RCBO); all from the consumer unit in the utility
Lifecycle
Stages follow the RIBA Plan of Work. Planning is approved (Gedling 2024/0465, demonstrator assumption), so the project is at stage 4, technical design. Records attach to the ID as each stage completes.
Records linked to this ID
Source and integrity
The files this ID is built from, with fingerprints that tie it to one exact version of each.
