What is Passive House?
Last year I was fortunate enough to undertake studies and become a certified Passive House Tradesperson. I had been interested in this particular course for several years and had done quite a bit of reading up on this style of building. It caught my attention as everything I was reading made sense, but couldn't understand why it had not gained much traction in Australia. I finally enrolled and went back to school. It was a very intense week of training with a few moments of information overload, but it was hands down the best course that I have undertaken. It completely opened my eyes about the building industry and the urgent need for change in Australia. Over the next few weeks, I will take you on a journey of what I learnt and go into more detail about Passive House.
Passive House is an internationally recognised construction concept that practices the highest standards of building. It can be defined as the most rigorous, voluntary, energy and health-based standard that the building industry can offer. It originated out of Germany and has been around for roughly 30 years.
For a home to be certified as a Passive House, there are 5 key principles that need to be followed.
1 - Airtightness
The building envelope must achieve extremely low air leakage. We want to stop any air leaking in or out. I consider this the most important part of a build and we will touch on this in more detail in a future post.
2 - Thermal Insulation
We all know what this is, so it shouldn't be news to anyone. All that is asked is that it is carried out correctly, is as thick as possible and is continuous.
3 - High Performing Windows
Quality windows are essential. These need to be triple glazed with multi low e coating to insulate the glass. They must be well sealed so no energy is lost as you can have all the glazing in the world, but if the window leaks it won't cut it.
4 - Mechanical Ventilation and Heat Recovery
This will provide you with clean and fresh air. It will lead to fewer pollutants in the air and reduce the risk of condensation and mould. It will also recover the heat or coolness that is already in the home that would otherwise be wasted.
5 - Thermal Bridge Free
All penetrations through the insulation must be kept to a minimum. This means avoiding materials that have a high conductivity rate (copper and aluminium) and using thermal breaks if required.
Although it may seem like there are a lot of stringent criteria that needs to be met for Passive House, these concepts are not new. A lot of these principles simply involve carrying out tasks that we already would for a standard home, but implementing them to a higher standard. We already insulate our home, however a lot of the time it is not installed correctly with gaps left in many spots. Instead we should be installing this continuously with no gaps. We are already putting windows in our home, however generally they are leaky and not well sealed. Instead we would install well-sealed triple glazed windows. We are also currently attempting to put an external membrane on our homes, however little care is taken when installing it. Instead we should be using the correct products, taping our joins and creating an airtight building. Most of the requirements for Passive House are not out of the ordinary, they just need to be implemented to the highest standard possible.
So what's so good about these homes?
It's not all about being green or trying to be sustainable, but about using data and science to build a home that will last the test of time and perform well.
Data shows that a Passive House will consume up to 90% less heating and cooling than compared to a standard build. We are also able to control the ventilation of these homes through the HRV System which provides clean fresh air, making them great for people with allergies or who are asthmatic. It helps remove pollen and dust from the air, limiting your exposure to any harmful triggers. These homes will also remain habitable for a longer period when there are power outages compared to a conventional type of build – especially during Australia’s summer heatwaves. Lastly, these homes will last. Most renovations are built using a 30-year mortgage. There is no return for investment on these loans and in more cases than not, these homes will need to be updated to be future-proofed. We don't know exactly how long a Passive House will last (many experts believe up to 100 years) but those built 30 years ago are still seeing the same performance compared to when they were built. They also qualify for reduced rates on your mortgage through green lending, as there is less risk associated with them.
A Passive House is long-lasting quality. If you build quality, you should only need to build once. But if you build cheap, be prepared to build twice or even thrice. We all want a home that is comfortable and healthy, more so now than ever. A Passive House is a great way to live and we can't wait to share more of our thoughts as to why you should go Passive. If you're currently thinking of building and are interested in building Passive, please reach out for a chat.