Build it right.
Avoid energy regrets for decades.
The decisions you make during design and construction lock in your home's energy performance, bills, comfort and carbon footprint for 50+ years. Our guidance and scoring system help you get it right the first time.
Transparent • Data-driven • No vendor lock-in
Working with an architect? See the professional design-brief view · Browse a sample project
What matters most for your build?
Pick a priority to see how pathway recommendations shift — without changing the underlying score. Use this as a conversation starter with your architect or builder. Planning aid only; not SAP, PHPP, or HEM certification.
Preference-aligned pathway "Efficient Electrified" — readiness not evaluated; preference order only (score unchanged).
Envelope targets
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.
Research & sources
Linked, not compliance proof5 Critical Design Decisions
They sit on the areas scored today. Solar's 12% is reserved and currently adds 0. With no certificate, the highest possible score today is about 88. With the EPC anchor, the highest possible score today is about 90.
Thermal Envelope & Airtightness
Target U-values ≤0.15 W/m²K walls/roof, airtightness <1.0 ACH50, eliminate thermal bridges. Consider Passive House or equivalent.
Choosing cheap insulation or skipping blower-door test locks in high heat loss forever.
Heating & Cooling System
Install air/ground source heat pump from day one. Size correctly using heat loss calculation. Pair with underfloor or low-temp emitters.
Installing gas boiler "just in case" or oversizing systems wastes money and carbon.
Ventilation Strategy
Whole-house MVHR with ≥85% efficiency. Design for excellent air quality without energy penalty.
Relying on trickle vents or poor MVHR specification leads to stuffy homes or high running costs.
Solar PV, Battery & Orientation
Leave roof space for PV, a battery, and EV charging. That planning does not add points to the Health Score.
Poor roof design that prevents a later solar or battery install.
Hot Water & Plumbing
Heat-pump water heater or solar thermal + insulated pipe runs. Consider drain-water heat recovery.
Standard electric immersion or uninsulated pipes.
Your New-Build Checklist
Calculate accurate heat loss before specifying any plant
Model your home in our Score tool at every design stage
Prioritise fabric-first (envelope before systems)
Design for future flexibility options — plan space and controls for batteries and EV charging where relevant
Get independent energy consultant or use our methodology as brief for your architect
Plan for monitoring from day one (sensors, dashboard integration)
Our methodology translates your architect's drawings and specifications directly into a 0-100 Evolving Home Score.
- → Early concept: test different insulation specs
- → Planning stage: compare heat pump vs other options
- → Final spec: validate against real performance benchmarks
Takes 60 seconds • Free • No sign-up required for basic modelling
Size your build in context
Pick a climate profile and rough floor area to see indicative heat-loss bands and risk flags — the same planning logic architects use, in a lighter homeowner view. Planning aid only; not SAP, PHPP, or HEM certification.
MVHR with summer bypass for overheating seasons
Defaults to 120 m² if left blank — adjust when you have concept drawings.
What matters most for your build?
Indicative quantity ranges
Planning bands only — not SAP, PHPP, or HEM model outputs. Verify with qualified assessor.
Indicative bands only — verify with a qualified assessor before specification lock-in.
Ready to build a high-scoring home?
Use the score tool, share your plans with us, or read the full open methodology behind the scoring engine.
View sample PassportFor architects — design-stage briefs with sources
Part of Evolving Home's transparent approach to home energy performance.
Built for self-builders, architects, and forward-thinking developers.