The design principle Passive House or Passivehaus began in Germany in the early 1990s. It’s a certified standard of building that aims to provide homeowners with a healthy, comfortable living environment in buildings that are energy efficient. By creating an insulated building envelope, that also acts as an airtight barrier, occupants get the pleasure of enjoying fresh, filtered air that is kept a consistent 20-25 degrees year-round, no matter what extreme weather conditions are happening on the outside.
Implementing passive house principles into building design has proven to save up to 90% of energy usage in the building. So not only are you helping fight climate change, you’re also saving huge amounts on energy bills and providing a healthy home for your family.
The 5 principles behind passive house are…
Step one: Thermal insulation
In a passive home, walls are well-insulated in a continuous and complete barrier, which keeps internal temperatures at a comfortable, natural level.
With a well-insulated home, it’s actually possible to keep the building warm via the use of kitchen appliances, energy from light bulbs and human body temperature, if needed.
It’s a myth, however, that you wouldn’t have any form of heating or cooling system within a passive home. It would just have limited use.
Step two: Thermal bridge–free construction
Thermal bridges are weak points in the building fabric that allow heat to travel through the walls. This occurs in places where the interior structure changes direction, when different materials connect and around window openings. This is a common problem in construction within Australia where there is often insufficient insulation and lack of an airtight barrier.
Thermal bridge–free construction is an integral part of passive home design, because all the work of insulating can be undone through these thermal highways. Be sure to consult an experience builder before construction to ensure weak points in the design are kept to a minimum.
Step three: High performance windows
Eighty per cent of homes in Australia still use single pane glass, which is known as a poor insulator because it makes the home too hot in summer and too cold in winter. Passive homes, however, use double or triple glazed windows, which is fantastic for maintaining temperatures.
The orientation of a passive home should be carefully considered as well. The house should be built in a way that sun can stream in through north-facing windows proportioned to the house size, so that solar energy heats the house for free. With a large roof that extends outwards, shutters on the windows and intentional shading from trees, a passive house will be sheltered from that hot afternoon sun, so that it remains comfortable in summer.
Step four: Creating an airtight building envelope
A passive home is about creating an airtight building envelope. The building envelope of a house consists of the roof, subfloor, exterior doors, windows and walls – basically any structure that separates the outside environment from the inside.
An airtight building envelope prevents leaks where heat could escape, as well as draughts that could see cold air to seep in during winter and hot air to flow through in summer. Windows, doors and other openings are carefully sealed through rigorous testing so the internal temperature of your home can be controlled year-round.
Step five: Heat recovery ventilation
A vital part of passive home design is the heat recovery ventilation (HRV) system, which allows for air circulation without losing any heat. Fresh air, free of the toxins that can be found in air flowing in through windows, is filtered into the house.
Stale air is removed, but not without first extracting the heat from it. The heat exchanger then uses this to heat the house. With this system, heat is recycled while the air is always fresh. So, in your home, you can still open the windows, but you don’t need to rely on them to enjoy fresh air.
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Sticking to these 5 core principles will help create a high performing, sustainable building that will last a very long time. Our Director Jon has successfully completed the Certified Passive House Tradesperson course, so if you want to know if these techniques can be implemented on your renovation project, or your thinking of a knock down re-build, then get in touch today for a FREE consultation!