What is a PassiveHouse?
A “PassiveHouse” is any building that has been designed and formally certified by the “Passive Haus Institute” (PHI) to be comfortable, healthy, and have very low heating/cooling energy demand. The certification process is entirely voluntary, it’s rigorous, it’s based in engineering and physics, and yes, it costs a little bit of money to undertake – however the upfront design and certification costs are paid back many times over in reduced running costs over the life of the building.
Why bother with a Certified Passive House?
Any Building Designer or Architect can design a comfortable, healthy and efficient building, right? There are loads of environmentally conscious designers out there, why bother with certification?
To us, it’s about rigorous independent proof of design effectiveness, and quality control throughout design & construction.
Passive House certification ensures that your home will be as comfortable, healthy and energy efficient as your designer/architect promises you.
As a consumer looking to spend a life changing amount of money on a home that you really want to be healthy, comfortable and efficient, it is comforting to rely on rigorous mathematical modelling and independent verification of your home’s performance. Alternatively, you can simply rely on your designer’s experience, rules of thumb, the National Construction Code, or worse yet, gut feel.
OK, but what is a PassiveHouse?
Passive House is a design approach – a way of thinking about buildings. It is not a construction system, nor a material, nor an aesthetic style.
In Australia we have a long and proud history of starting with the shape and use of our homes to meet the needs of occupants. With an abundance of relatively cheap energy over previous decades, there has historically been little need to worry about energy consumption. However we are becoming increasingly aware of the impact of excessive energy use on global heating. This awareness triggered the NatHERS energy rating system and regulatory hurdles to reduce energy use, which are having some impact across our country. Unfortunately, most people still build merely code compliant houses - ie. the worst house legally allowable.
We believe that our current regulatory ambition is not good enough - not for us today, nor for our children tomorrow. Our homes should use much less energy than is currently allowable, while simultaneously being comfortable and healthy. The PassiveHaus standard helps us design and build towards this ambition in a more holistic, repeatable and achievable way, resulting in seriously low energy consumption, excellent comfort and healthy indoor environments.
PassiveHouse does not specify how or what you build with, only how it should perform in everyday use – it’s a performance standard only. A PassiveHouse can be whatever you want it to be as far as looks, style, materials, finishes and construction system are concerned – some choices are easier to realise than others, but through the performance standard, it will always be healthy, comfortable and efficient.
What makes a Passive House special – from the occupants’ perspective?
- Fresh, filtered air is constantly supplied throughout the home. The air quality is comparable to having windows open 24/7. Only without the dust, pollen, noise and cold breeze.
- Mould on internal surfaces (a far too common resident in Australian homes) is avoided by ensuring temperature and humidity fall outside of the “mould growth window”, and additional modelling can be done to avoid its growth within the walls of your home too.
- Internal air temperature can be maintained at 20-25°C with extremely little heating/cooling energy required, regardless of the external air temperature.
- Drafts are virtually non-existent, because your home is almost airtight. No more cold ankles.
- Windows are neither too hot, nor too cold to sit near. No more “cold seat in the room” to avoid.
- Because its nearly airtight, external noise is heavily muted leading to a very calm and quiet interior.
- Energy use for heating/cooling is ~90% less than older style homes, and perhaps 75% less than new build homes meeting current minimum energy standards. This amounts to a significant cost saving, to the tune of several $1000’s per year compared to a typical home.
- The heater/cooler is rarely needed, and when it is, the internal temperature reacts quickly and then stays at that temperature for a comparatively long time.
- The house is designed to do the work for you. It is designed with passive solar principles in mind to minimise energy use, but can be very forgiving if you (for example) forget to close the external blinds in summer.
- A PassiveHouse does not rely on the occupants driving the house perfectly everyday (opening and closing windows, blinds, shutters, etc at the right times in the right places). Proactive occupants can really boost the energy efficiency, but even with inactive occupants, the house will perform quite well. Because of the care, love and attention given during the design and construction phases, achieving excellent energy efficiency during the buildings lifetime is assured.
This all seems too good to be true at first. It even seems Utopian. But it’s not.
In Australia, we have been generally blessed with a more forgiving climate than much of Europe. The methodology and technical tools developed overseas to live in harsher climates have led to healthy, comfortable and efficient homes – exactly the sort of home we want in Australia. As consumers we can demand more of the building industry – we can expect our homes to be healthy, comfortable and efficient – and we can expect them to perform as advertised.
The construction industry here is beginning to awaken to the potential of Passivehaus; we are starting to see extraordinary examples of the application of PassiveHaus design on a daily basis. And now savvy home owners and developers are demanding it across the country.
If you are thinking of building or renovating, reach out. Lets chat about PassivHaus, maybe its for you too.
You only get one chance to get the building fabric right.
Reach out to us now.