Back to architect homeSample project — mock data

Sample — 3-bed semi-detached (mock)

Energy independence north star · SW postcode archetype

Evidence grade

Confidence

Medium — mostly estimated

Floor area

118 m²

Download this mock brief as JSON, Markdown, or PDF — planning aid only, not a certified export.

Evolving Home · Architect brief

Sample — 3-bed semi-detached (mock)

New buildNorth star: Energy independenceactive roof

For your 118 m² semi project · BS8 1QU — Energy independence north star

Generated 09/07/2026, 08:26:38

Design brief summary

Preference-aligned pathway "Active Roof" — readiness not evaluated; preference order only (score unchanged).

Envelope targets

walls: U ≤ 0.18 W/m²K (concept target)
roof: U ≤ 0.12 W/m²K (concept target)
airtightness: ≤ 1.0 ACH @ 50 Pa (design target)
glazing: Balance g-value and Uw by orientation; avoid overglazing south façades

Risk flags

[medium] Overglazing risk — Large unshaded south glazing increases overheating before heating load drops.
[medium] Thermal bridge detailing — Junctions at balconies, corners, and extension ties need explicit psi-value strategy.

This pack is design-stage decision support from Evolving Home. It is not a SAP calculation, PHPP balance, HEM assessment, or Energy Performance Certificate. A qualified On Construction Domestic Energy Assessor (or PHPP consultant) must produce the authoritative compliance model for Building Regulations and/or Passive House certification.

Passive House (PHPP) certification and UK Building Regulations (SAP/HEM) are separate workflows. This brief supports early design intent only.

Assumptions ledger (compact)

Key assumptions, evidence gaps, and verification hooks for consultant handoff.

Project assumptionsEstimated
For your 118 m² semi project · BS8 1QU — Energy independence north star
Project assumptionsEstimated
Recommended pathway (preference-ranked): active roof — unknown
Project assumptionsEstimated
Climate profile: Temperate (UK)
Project assumptionsEstimated
2 storeys (design intent)
Project assumptionsEstimated
Budget sensitivity: balanced
Envelope & glazingEstimated
walls: U ≤ 0.18 W/m²K (concept target)
Envelope & glazingEstimated
roof: U ≤ 0.12 W/m²K (concept target)
Envelope & glazingEstimated
airtightness: ≤ 1.0 ACH @ 50 Pa (design target)
Envelope & glazingEstimated
glazing: Balance g-value and Uw by orientation; avoid overglazing south façades
Envelope & glazingEstimated
Glazing: ~18% floor area — balanced glazing
Evidence gapsMissing
Loft depth / roof build-up not verified on site
Evidence gapsMissing
No blower-door test scheduled — airtightness target is design intent only

Consultant handoff preview

Live previewPreview only

Project assumptions

·For your 118 m² semi project · BS8 1QU — Energy independence north star
·Recommended pathway (preference-ranked): active roof — unknown
·Climate profile: Temperate (UK)
·2 storeys (design intent)
·Budget sensitivity: balanced

Envelope & glazing

·walls: U ≤ 0.18 W/m²K (concept target)
·roof: U ≤ 0.12 W/m²K (concept target)
·airtightness: ≤ 1.0 ACH @ 50 Pa (design target)
·glazing: Balance g-value and Uw by orientation; avoid overglazing south façades
·Glazing: ~18% floor area — balanced glazing

Evidence gaps

·Loft depth / roof build-up not verified on site
·No blower-door test scheduled — airtightness target is design intent only

Questions for SAP / HEM assessor

·Confirm notional vs actual specification path
·Overheating screening method for primary living rooms
·Renewable contribution accounting and battery assumptions

Questions for PHPP consultant

·Thermal bridge Psi-values for preferred junction details
·Heating/cooling load after fabric specification locked
·Ventilation summer bypass strategy with MVHR

Glazing risk: LowThermal mass opportunity: MediumSolar potential: HighCooling load flag: Low

Beta — Planning viewnew buildactive roof

Preference-aligned pathway "Active Roof" — readiness not evaluated; preference order only (score unchanged).

Envelope targets

walls: U ≤ 0.18 W/m²K (concept target) Source
roof: U ≤ 0.12 W/m²K (concept target) Source
airtightness: ≤ 1.0 ACH @ 50 Pa (design target) Source
glazing: Balance g-value and Uw by orientation; avoid overglazing south façades Source

Risk flags

[medium] Overglazing risk — Large unshaded south glazing increases overheating before heating load drops.
[medium] Thermal bridge detailing — Junctions at balconies, corners, and extension ties need explicit psi-value strategy.

Passive House (PHPP) certification and UK Building Regulations (SAP/HEM) are separate workflows. This brief supports early design intent only.

Research & sources

Linked, not compliance proof

Indicative quantity ranges

Planning bands only — not SAP, PHPP, or HEM model outputs. Verify with qualified assessor.

Peak heat loss

5–10 kW (indicative peak, not SAP/PHPP)

Annual demand band

4130–6490 kWh/yr space heating/cooling demand band

Overheating basis

Moderate — confirm with orientation and glazing schedule

PV indicative range

4.7–8.3 kW roof PV indicative range (subject to shading and roof area)

Ventilation assumption

Whole-house MVHR when airtightness target ≤ 1.5 ACH50

Confidence

Medium — multiple inputs captured; pathway: active roof

North-star comparison

Re-ranks narrative — score unchanged unless inputs change

Energy independence

Pathway order: Active Roof → Ground-Coupled

Size solar and storage after demand reduction; plan for future battery and EV integration.

Risk focus: Grid export and battery economics uncertain at concept

Sustainability

Pathway order: Efficient Electrified → Ground-Coupled

Lock envelope performance and thermal bridge strategy at concept stage; compare embodied vs operational tradeoffs.

Risk focus: Embodied carbon tradeoffs need LCA review

ROI

Pathway order: Efficient Electrified → Active Roof

Stage investments by payback confidence; electrify heating only after fabric targets are set.

Risk focus: Payback bands directional only — not quoted here

Max-techExperimental

Pathway order: Active Roof → Ground-Coupled

Treat advanced controls and grid services as layered options — never substitutes for envelope fundamentals.

Risk focus: Higher uncertainty — experimental controls and VPP

Design-stage scenarios

Compare options at concept — demo planning view; not a lodged compliance model.

Baseline / compliant-minimum

Meet regulatory intent with lowest upfront disruption — acceptable for tight budgets.

Medium confidence

Main moves

· Target Part L notional building U-values at concept
· Standard double glazing; MVHR deferred
· ASHP sized on preliminary heat loss

Risks: Overheating on south rooms; Higher lifetime bills vs fabric-first; Future retrofit harder

Fabric-first low-risk

Lock envelope performance early; smallest plant for long-run comfort.

Medium confidence

Main moves

· U ≤ 0.15 walls/roof concept targets
· Airtightness ≤ 1.0 ACH50 design intent
· Balanced glazing with shading strategy
· MVHR with summer bypass

Risks: Cost premium vs baseline; Thermal bridge detailing at junctions

Efficient electrified / PV-ready

Electrify heat and hot water with roof optimised for self-consumption.

Low confidence

Main moves

· Fabric-first envelope (moderate ambition)
· ASHP + cylinder sized after demand reduction
· South/east-west roof reserved for ~4–6 kWp
· Future battery / EV circuit provision

Risks: Oversizing PV before demand reduction; Grid export assumptions

Evidence ladder

Recommendations sharpen as facts move from estimated → known. Score confidence bands reflect the same honesty.

Known

Client-stated floor area, confirmed build type

Estimated

U-values from archetype; glazing ratio from concept drawings

Missing

Blower-door result, loft depth, wall construction confirmation

What improves confidence: site survey, EPC lodgement, blower-door test, measured post-occupancy data (planned).

Compliance-adjacent checks

Flags for professional review — Evolving Home does not sign off Part L, Part O, SAP, PHPP, or HEM.

Issue	Why it matters	Who verifies	Evidence	Next action
Part L / energy performancePart L	Fabric and plant choices affect notional vs actual performance path.	SAP / HEM assessor or regional equivalent	partial	Lock U-value targets and confirm assessment route at technical design
Ventilation strategyVentilation	MVHR requires airtightness QA and summer bypass planning.	Ventilation designer / assessor	partial	Confirm ACH target and MVHR summer bypass with assessor
Heating plant sizingHeating	Heat pump sizing must follow fabric-first heat loss, not rule-of-thumb.	Heating engineer / MCS installer	partial	Align with Air-source heat pump sized after heat loss — low-temperature distribution…
Design intent onlyDesign intent	Evolving Home does not lodge SAP, PHPP, or HEM files.	Qualified assessor	assumed	Export intent pack and schedule formal modelling

Client meeting one-pager

Plain EnglishPlanning aid

Share with clients before consultant appointments — highlights intent, risks, and decisions without certification language.

For your 118 m² semi project · BS8 1QU — Energy independence north star

Size solar and storage after demand reduction; plan for future battery and EV integration. This brief ranks pathways for your stated priority — it does not replace accredited energy modelling.

Top risks to discuss

Overglazing risk — Large unshaded south glazing increases overheating before heating load drops.
Thermal bridge detailing — Junctions at balconies, corners, and extension ties need explicit psi-value strategy.

Client decisions

Balance daylight and heat loss with orientation-aware glazing
Heating route: ashp — confirm emitter sizing after fabric targets lock
Ventilation: whole-house MVHR — align with airtightness target
Budget sensitivity (balanced) — trade-offs between fabric depth and plant complexity
North-star priority: energy independence — shapes pathway ranking in this brief

Consultant verification next steps

Book SAP / HEM assessor early — confirm notional vs actual specification path
Schedule overheating screening for primary living rooms and high-glazing façades
Lock envelope U-values and airtightness QA plan before plant sizing
Model renewable contribution and storage assumptions with assessor

Consultant handoff preview

Live previewPreview only

For your 118 m² semi project · BS8 1QU — Energy independence north star. Illustrative pack contents — not a lodged SAP, PHPP, or HEM file. Pro exports include versioned assumptions from your saved project.

Project assumptions

·For your 118 m² semi project · BS8 1QU — Energy independence north star
·Recommended pathway (preference-ranked): active roof — unknown
·Climate profile: Temperate (UK)
·2 storeys (design intent)
·Budget sensitivity: balanced

Envelope & glazing

·walls: U ≤ 0.18 W/m²K (concept target)
·roof: U ≤ 0.12 W/m²K (concept target)
·airtightness: ≤ 1.0 ACH @ 50 Pa (design target)
·glazing: Balance g-value and Uw by orientation; avoid overglazing south façades
·Glazing: ~18% floor area — balanced glazing

Evidence gaps

·Loft depth / roof build-up not verified on site
·No blower-door test scheduled — airtightness target is design intent only

Questions for SAP / HEM assessor

·Confirm notional vs actual specification path
·Overheating screening method for primary living rooms
·Renewable contribution accounting and battery assumptions

Questions for PHPP consultant

·Thermal bridge Psi-values for preferred junction details
·Heating/cooling load after fabric specification locked
·Ventilation summer bypass strategy with MVHR

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