Originally developed in German in 1990s, Passive House is a dream goal for everyone who wishes to live in an energy efficient yet healthy and comfortable home. So what makes a house a Passive house? Here are some concepts.
- Average indoor temperature should be around 20°C – 25°C, despite of winter or summer.
- Heating and cooling demand < 15 kWh/m2 a year, which means < $90/year for a 100 m2 house.
- Humidity < 12g/kg for more than 20% of the year.
- Airtightness < 0.6ACH50
- Overall energy demand < 60kwh/m2/yr including heating, cooling, fixtures and appliances.
Tips to achieve Passive House
- Thermal insulation: Must be continuous throughout the building, including around the perimeter of the slab. In some climate zones, it is necessary to have insulation under the slab.
- Minimise thermal bridge: Eliminate any conductivity which may cause condensation. This means the use of those construction materials such as aluminium, steel and concrete should be avoided.
- Airtightness: No air gap around windows and doors or avoid ceiling penetrations such as downlights is one of the solutions to control water vapour transfer. Oriented strand board, plywood or specialised membranes are effective solutions to walls, roof and floor.
- High-performance windows and doors: Must be very well sealed and double or triple glazed. They also need to have appropriate shading to control the solar heat gain in seasons.
- Adequate ventilation: Even though Passive House requires airtightness, maintaining fresh air for occupants is essential. Heat exchanger is a low-cost system that can do the job well. It allows the outgoing air and incoming air interchange heat energy at the same temperature. So there will be no temperature shock to the occupants.
Currently, more people are looking at Passive House designs for their sweet homes. Not only because it works at its best in providing thermal comfort, but it is also a sustainable option, which will last long and more importantly, not hurt your purse for energy bills.
If you need BASIX or energy rating for your new or existing homes or projects, please do not hesitate to contact us for a quick chat.
Ref: https://www.yourhome.gov.au/passive-design/passive-house
