There is a saying in the sustainable housing design industry “build tight and ventilate right“.
Many of us have lived the majority of our lives in what are now known as “leaky homes”. These homes have many places where unwanted air exchanges occur and this is what contributes to our heating and cooling bills. According to testing conducted by the CSIRO, some of Australia’s older homes (particularly weatherboards on stumps) have an hourly air change rate ( ACH is the measurement of how many times per hour the air is exchanged in a house) of between 30 and 50; with the average coming in at 15.4 ACH; and the average ACH of homes built at The Cape come in at under 5 ACH.
There is a lot to know about airtightness when designing a home and it is a fine line ensuring toxic gasses can’t build up in a very air-tight home which has gas appliance (not applicable at The Cape as gas is not supplied to the development); knowing when to adopt air exchange technologies for passive homes; and preventing problems associated with the buildup of condensation. Thankfully, as consumers, we don’t need to have these skills and can rely on our sustainable architects, designers, and builders to get this balancing act just right.
However, there are a few things we can learn about living in such homes, to ensure the way we go about our daily lives don’t contribute to problems occurring down the track – and that is where the saying “design tight and ventilate right” comes into it. When we live in a well designed, draught-proof home, we open windows and doors because we want to, not because we have to. If you are noticing a little bit of condensation on your windows, you can do some simple things like ensuring you run your exhaust fans in the kitchen and the bathroom; and cracking open a south facing window a little overnight can help prevent condensation.
If you would like to read more about how condensation is managed in buildings and the types of things that experts consider when designing and building your new home, you can follow the resource links below.
Condensation in buildings handbook (Australian Building Codes Board)
Condensation management (written by Jenny Edwards for Renew Magazine)
Our Cape Life 