Beautiful one day, perfect the next. This is what the Queensland Government tells the rest of us in Australia anyway. But how does this abundance of sunshine relate to how we heat and cool our houses?
In 2013 the CSIRO carried out a study "The evaluation of 5-star Energy Efficiency Standard for residential buildings" in which they studied 414 houses in Brisbane, Adelaide, and Melbourne. They found that the winter heating predicted in the regulatory software tools had relatively good alignment with actual outcomes. But when it comes to cooling our houses in the sunshine state (QLD), the gateway to the outback (SA) and the place to be (VIC)… there was something amiss.
CSIRO found "The average cooling energy use in summer was greater in (…) higher-rated houses in Brisbane and Melbourne. (…) However, it is not clear whether this was due to (…) behavioural factors (…) [including] the extent of window opening and closing during summer."
Obviously if you face the majority of your windows east or west you will increase your cooling requirements. This is relatively well known especially for people who have ever lived in a house or apartment with large window areas facing the morning or afternoon sun. The natural response to combat this issue is to open your windows to ventilate the heat out of your living room. That’s fine if you are at home to do this.
Within the Regulatory system the assumptions are that you are at home and you are constantly monitoring the indoor and outdoor temperatures to determine if the time is right to open your windows for cross flow and receive mother natures "free-cooling" effect.
Design engineers will often carry out "What-if" scenarios. This is an approach taken to limit the risk of failure of any aspect in an engineering project. So, I asked myself, what-if…. I was too lazy, too old, too frail or too sensitive to outdoor pollution or noise and did not open my windows when I was meant to?
Carrying out some calculations using the CSIRO regulatory software on the CSR House design with a 6 star specification located in Schofields (Western Sydney), it was found that the cooling requirement would increase by 278 – 382% if the windows were never opened, depending on which way the house faces. This is big… really big!
The truth (i.e reality) probably lies somewhere in between 100-382% increase above the predicted regulatory calculations depending on the occupants.
However, the future of houses will not rely on occupants to limit cooling; after all we are a developed country with access to world class education and knowledge, so the house will do the thinking for you. The technologies exist and fall into a broad category of "smart ventilation." The R&D team at CSR Edmonds has developed a world class technology for this real world issue. CSR Edmonds Odyssey is designed to prevent this exact scenario by incorporating temperature sensors and automated ventilation controls that will do what the regulators expect you to do, take advantage of Mother Nature’s free cooling and prevent summer energy bill shock.
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