Design principles
Passive House principles: how to read the building envelope
A building can look modest and have a carefully resolved envelope; a dramatic green facade can tell you little about its energy demand. Passive House is a performance standard with a verification process. To read it architecturally, follow the boundary between inside and outside, then ask how the design is modelled, built and checked. This guide explains the principles and the evidence to request, rather than assigning certification or a comfort result to a photographed building.
Start with the exact claim
Separate a design intention, a certified component and a certified building.
The Passive House Institute publishes building criteria for Passive House, EnerPHit and PHI Low Energy Building. These are distinct standards, not interchangeable labels. The institute also certifies components; a certificate for a window does not certify the building containing it.
Source: Passive House Institute: Building certification
Source: Passive House Institute: Building and component certification
Copy the wording used for the project. Does it say designed to a standard, certification in progress, or certified? Ask which building, stage and certificate it refers to. For an apartment, establish whether the evidence covers the block, a particular part or the dwelling you are considering. Keep an unverified claim on the open-questions list.
| Statement | Useful next document | What it does not establish |
|---|---|---|
| Designed using Passive House principles | Design brief and performance model | Completed building certification |
| Certified component | Component certificate and installation detail | Whole-building performance |
| Certified building | Building certificate with scope and standard | Your household’s future bills |
| Measured energy use | Period, meters, occupancy and weather context | A directly comparable result for another home |
Trace one continuous envelope
Read insulation, airtightness and thermal bridges as connected layers.
Australian government guidance describes a fabric-first approach: insulation controls heat transfer, an airtight enclosure limits uncontrolled leakage, and thermal-bridge reduction addresses local paths for heat flow through the envelope. These functions need to work together; none can be inferred from wall thickness in a brochure.
Source: Australian Government Your Home: Passive House
On a section, trace the outside boundary of the conditioned space through wall, roof, floor and window. Where a balcony, beam or entrance meets it, ask for the junction detail. The question is how the intended layers continue at that point, not whether the facade appears heavy or lightweight.
Repeat the exercise at a service penetration and the edge of a window. Record the relevant detail number and revision. This is a way to organise a conversation with the design team; choosing materials, assessing moisture risk and approving junctions require project-specific technical work.
Read the window in its climate
The frame, glass, installation and shading belong to the same question.
The PHI building certification guide explains that measures depend on the local climate. Its examples distinguish window strategies in colder and warmer settings. There is no reason to transfer one glazing specification or orientation rule to every city simply because the same standard is being discussed.
Source: Passive House Institute: Building Certification Guide
Locate the exact window in a seasonal shading study. Ask what the frame and installed junction contribute, how sunlight is controlled and which parts open. Compare the bedroom at night with the living room in the afternoon rather than applying one judgement to all glazing.
A deep balcony may shade a window at one solar angle and leave it exposed at another. If that question matters, request the study for the actual elevation and floor. A coloured thermal image or a sunny rendering needs its date, method and context before it becomes evidence.
Airtightness and ventilation do different jobs
Ask both how uncontrolled leakage is tested and how planned fresh air reaches the rooms.
Your Home identifies airtightness, mechanical ventilation with heat recovery and high-performance windows among the core Passive House principles. Airtightness concerns the enclosure; it does not mean that a home is intended to operate without fresh air. The ventilation arrangement needs its own explanation.
Source: Australian Government Your Home: Passive House
Request the intended supply, extract and transfer routes on the apartment plan. What happens with bedroom doors closed? Where are controls, filters and access for servicing? Ask for the commissioning record and the resident instructions alongside the airtightness test result.
Distinguish the controlled system from optional window use and from the plan for cooking, cooling and unusual outdoor conditions. Ask the team how those situations are handled in this dwelling. Do not translate a low leakage result into an indoor-air-quality or noise guarantee.
Follow the chain from model to completed work
An integrated process matters as much as the list of five principles.
The Passivhaus Trust’s principles primer connects building fabric with performance and comfort criteria, modelling in the Passive House Planning Package and quality assurance through design, construction and commissioning. This explains why a checklist of products is an incomplete description of the approach.
Source: Passivhaus Trust: Principles primer
Make a simple evidence sequence: current model, coordinated drawings, construction checks, test results and any certification. Ask what changed between the design version and the completed work, and how those changes were reflected in the assessment. If the building is unfinished, record which items are still future commitments.
Compare scope before comparing energy figures
Keep performance evidence separate from a forecast of your bills.
For two homes, put the standard, certification scope, climate, model version and available measurements on separate lines. Ask whether an energy figure is a design calculation or metered use, which area definition it uses and which services it includes. Leave a figure unranked when the comparison basis is missing.
Then return to the lived questions: room arrangement, summer exposure, controls you can understand and maintenance you can reach. A performance standard is a particular form of evidence, not a substitute for checking whether the actual apartment fits your routine. Do not assume a named oyopo project is certified unless its own verified documentation says so.
Bring the performance questions back to the exact apartment plan
Questions to take with you
- Record the exact standard and whether the claim is proposed, in progress or certified.
- Check the scope and applicable version of the certificate.
- Trace the envelope through a balcony, window and service junction.
- Review window exposure and shading for the local climate.
- Keep airtightness testing separate from ventilation commissioning.
- Identify resident controls, filter access and maintenance responsibility.
- Compare energy figures only on a documented common basis.
How this guide was prepared
oyopo combines original architectural analysis with published information from architects and project teams. Sources identify the basis for project facts. The review date records the latest content check; design intentions and proposed facilities are distinguished from completed work. These articles are not site inspections or independent performance assessments.
Sources and further reading
Passive House Institute: Building certificationOfficial standards and current certification criteria entry point. Check the version applicable to the actual certification process.
Australian Government Your Home: Passive HouseExplanatory building-physics guidance, not a certificate or an energy assessment for a featured project.
Passive House Institute: Building Certification GuideFive principles and climate-dependent design measures. No universal construction specification is reproduced here.
Passive House Institute: Building and component certificationDistinguishes standards, building certificates and component certification.
Passivhaus Trust: Principles primer2025 explanation by the UK professional organisation of the integrated design and quality-assurance approach.
