Does air tightness matter in Australia?

air tightness matter in Australia

There is an embedded notion in Australia we do not need to worry about making our houses airtight (or energy efficient for that matter) because our climate isn’t extreme enough. We don’t have annual snow fall across much of our lands and we have air conditioners. Just crank the A/C on a hot day, heater on a cool day and she’ll be right mate. I’d like to unpack this a little bit as I believe it is not only those who live in arctic conditions that care about:

  • Energy wastage
  • Being comfortable
  • Healthy indoor air or
  • Mould


I think that the first reaction to the concept of air tightness is simply one of confusion and also of fear. Confusion as to why air tightness is necessary, fear of the additional cost of addressing it and anecdotally, I have found that there is a fear of lack of fresh air and even suffocation in an air tight home. See below for a discussion of each of these points.

Why is improved air tightness necessary in Australia?

I did a bit of a Google and have found that across Australia, temperatures can regularly get down to -5 Celsius or up to 45 degrees Celsius every single year, with the tropical climate zones also getting extreme levels of humidity for large portions of the year (up to 100%). So we certainly do have extreme conditions in many areas, which in my book, validates the need to pay attention to detail when building the structures that will house and protect us from the elements and that we will be paying for for many years. Looking after common air leakage pathways is a simple process and is the easiest and cheapest way to take control over the conditions inside your home.

Additional Cost

Air tightness detailing can be as simple or as detailed as you like. On the simple end, you engage a consultant to draw a red pen line around your air barrier and then educate the trades to pay attention to detail around penetrations along that line (say… approximately $500 in consulting fees plus some caulking). On the detailed end, you are having a full schematic review of your air barrier, purchasing and installing air tightness layers in your walls and ceiling and taping and installing HRV systems (this will run into thousands). There is broad scope between the two and any level of awareness and attention put on air tightness is an improvement on the current standard building practice and so I encourage you to start simple.

Indoor Air Quality

Amongst the general public, as well as pockets of the architecture and construction industry not directly involved in energy efficiency, there is an association of suffocation with airtight buildings and I do understand why; the terminology sounds like you’re putting your head in a plastic bag! But I assure you, this is not the case at all.

On the simple, cheaper end of the scale, it is likely you will not be closing up your building envelope far enough to cause any indoor air quality issues. On the detailed end of the scale, an air tight home is continuously mechanically ventilated and will never be without clean, fresh air. In both scenarios, there is absolutely nothing stopping you from opening the windows up to allow air to run through your home or leaving your sliding door wide open.

Air tightness in Australia is not necessarily about combatting arctic conditions, although we do certainly experience extreme temperatures. It is primarily about obtaining improved control over the internal environment of your home; separating the inside from the outside and ensuring that any air that enters your home is entering either via doors and windows or filtered ventilation systems rather than through dirty, dusty wall cavities bringing with it dust mites, moisture and unwanted temperature fluctuations.

It’s not rocket science, just awareness!

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