In today’s world, a home cannot be defined as sustainable if it is not air tight and does not include mechanical ventialtion

There is enough information to understand the effects of poor indoor air quality on the occupants of a home, and if the occupant's health is put at risk, how is that sustainable?

If we look at what the term sustainable means, the Cambridge dictionary defines it as 'causing or made in a way that causes little or no damage to the environment and is, therefore, able to continue for a long time.'

It also defines the word environment as 'the air, water, and land in or on which people, animals and plants live.' The key word there is air, and this needs to be addressed.

Most of us spend a large percentage (90%) of our lives indoors, so we need to start thinking about the air quality in our homes. Poor indoor air quality may cause you to become sick in your own home (Google 'sick building syndrome'). So how can we call a home 'sustainable' if it fails to provide the occupants with a healthy environment?

(Hot tip, you probably shouldn't)

But you can only build airtight by using mechanical ventilation. Uncontrolled ventilation does not work, period. You are reliant on the occupants opening windows at the correct times of the day and at the mercy of the outdoor conditions. If it's freezing outside like it is at the moment, are you going to leave your windows open all day when you have just spent a small fortune heating the home?.... plus the WHO estimates that polluted outdoor air kills over 7 million people annually, so yeah let's bring that air inside without filtering it!!!

But hey, these are not just our thoughts; there are endless studies and data to back this up (see the slides above), and we will let that do the talking.

We understand that many elements need to be considered when discussing sustainability in homes, such as being conscious of our material choices, respecting our natural resources and optimising energy and water use. We are just saying that indoor air quality is one of the most important aspects of a sustainable home and shouldn't be ignored.

Being a Passive House builder in Melbourne means this is not an issue for us and the indoor air quality of our clients home is as good as it can be!

source - Passive Analytics

The idea of a leaky home is crap, you are entirely reliant on what is happening outside, you can see this on the left graph with the co2 levels (ie weather and convection).

The high-performance home on the right is super controlled, and it doesn’t matter what is happening outside; the system just does its thing