Thermal Performance & Passive Design Principles
Thermal comfort in Australia is climate-driven. A high-performing building isn’t “more expensive by default”—it is more intentional. This section covers passive design hierarchies, insulation continuity, and airtightness.
1. The Passive Design Hierarchy
- Orientation and zoning: put living spaces where they get beneficial sun; separate hot/cold zones where appropriate.
- Shading: block summer sun while allowing winter sun (especially north-facing glazing).
- Envelope: insulation, glazing, and airtightness are your main levers.
- Ventilation: cross-ventilation, night purging (climate permitting), and exhaust control in wet areas.
- Efficient systems: heating/cooling efficiency matters, but only after the envelope is right.
2. Insulation: Continuity Beats Nominal R-Value
Insulation performance collapses when it’s compressed, gapped, or discontinuous. Common failure points:
- downlights and ceiling penetrations,
- uninsulated bulkheads and soffits,
- missing insulation at corners and junctions,
- poorly detailed slab edges in some climates.
3. Airtightness: Comfort, Condensation, and Energy
Uncontrolled air leakage increases heating/cooling load and drives condensation risk. Airtightness is mostly about details: sealing wraps, taping laps, and properly detailing penetrations.
4. Glazing: The Most Expensive Square Metre on the Job
Glazing is a powerful comfort tool and a powerful defect tool. Treat window selection and installation as a critical package: flashing details, reveal sealing, and compatibility with wraps and cladding systems.