Five Key Elements of a Passive House
Exceptionally energy-efficient passive homes use 80-90% less energy than an average home. Designed to be resilient to temperature peaks, passive homes are a great choice for our Victorian weather. If you are interested in building a passive house along Victoria's south coast, you will want to understand the five design principles that make up a passive home.
Passive Home Design Principles
According to the Australian Passive House Association, a Passive House is designed and built in accordance with five simple building science principles:
Airtightness
Thermal insulation
Mechanical ventilation heat recovery
High-performance windows
Thermal bridge-free construction
1/ Airtightness
The cornerstone of every Passive House is its air-tight building envelope. To achieve this, it is essential to maintain a continuous airtight barrier around the home. Best practice typically involves establishing an airtight barrier on the inner surface of the thermal envelope. This guarantees minimal gaps and cracks, affording complete control over the internal environment and vastly enhancing thermal comfort, eliminating annoying draughts for good.
2/ Thermal Envelope
The key is to establish a continuous, fully insulated barrier around the entire building, including walls, floors, and ceilings. High-quality insulation is crucial, applied consistently with minimal breaks for structural elements and penetrations, ensuring optimal performance. It is important to acknowledge that a highly insulated house can be prone to overheating, especially during shoulder seasons. Implementing strategies such as cross ventilation and minimising east and west-facing glazing can help mitigate this issue.
3/ Mechanical ventilation heat recovery (MVHR)
This doesn’t imply that you’re restricted from opening your windows! In a Passive House, a Mechanical Heat Recovery Ventilation (MHRV) system continuously delivers filtered fresh air while removing stale air. These systems efficiently recover heat from the extracted air, effectively ventilating the home without placing added strain on heating or cooling systems. As buildings become more airtight, mechanical ventilation becomes essential for maintaining a healthy indoor environment.
4/ High-performance windows
Ensuring excellent insulation extends beyond the solid areas of your building envelope to include your windows. Say goodbye to single glazing; instead, opt for double or triple glazing with thermally broken or non-metal frames. Window size should be tailored to each orientation, allowing solar radiation to enter during winter for free heating while preventing excessive solar gain in summer. Additionally, pay attention to their sealing quality, as leaky windows are simply not acceptable.
5/ Thermal bridge free construction
While good insulation is crucial, it's important to recognize that it has its limits. Thermal bridges present vulnerabilities in the building envelope, enabling heat to escape. These can be likened to weaknesses in the building's defence, often occurring where insulation is interrupted, such as a balcony slab, window frames, structural steel or the junction between a wall and concrete foundation. Thermal bridges create cold spots within the building envelope, where moisture is prone to condense. This raises the risk of condensation buildup and subsequent mould growth, which are precisely the issues we aim to prevent.
Passive Home Builder for Geelong, Surf Coast and Bellarine
If you are looking for a passive home builder to help you design and build your custom home, Live Green Homes can provide the expertise to ensure your home aligns with the five passive home design principles. As certified Passive House tradespeople and consultants, Live Green Homes has experience designing custom passive homes that are energy-efficient and unique for our region.
Reach out to our team to learn why we are one of the preferred passive home builders in the Greater Geelong, Bellarine Peninsula and Surf Coast regions.