By Joe Scholz, Director, QED Environmental Services
Following on from my last post about cognitive effects of indoor environment, I’d like to provide some commentary on NABERS Indoor Environment versus Energy Ratings. This post derives from a second presentation I made to AIRAH’s 2017 Future of HVAC conference.
Certain highly energy efficient buildings are simultaneously hitting high NABERS IE ratings, for example:
|100 St Georges Terrace Perth||5.5 Star||6 Star|
|QV1 Perth||5 Star||4.5 Star|
|50 Carrington St, Sydney||4.5 Star||5 Star|
|50 Markus Clark||5.5 Star||5 Star|
This contrasts with a common misconception that quality indoor environment will always require excessive ventilation with the associated high energy usage. There is an element of balancing energy and air quality – you shouldn’t manage for one and forget about the other. In this post I provide some tips for improving NABERS IE for a given energy rating.
Whilst ventilation is extremely important to the quality of indoor air, it is not the only factor driving NABERS IE ratings see the table below.
Overall 40% of the rating comes from thermal services and strong results from hourly monitoring is required for the higher NABERS IE ratings. Every non-compliance in hourly logs reduces the score.
See the following graph indicating that compliance of hourly logs above 95% is absolutely required to achieve a rating of 4 stars or more.
Another 40% of the rating is ventilation based, through once-off testing of carbon dioxide, particulates and carbon monoxide. In temperate and sub-tropical climates it is advisable to conduct the testing at the time of year that HVAC economy cycles are operational as this brings in more fresh air. In addition CO2 sensor accuracy and calibration should be checked along with managing the set points to avoid inconsistent CO2 conditions per floor.
In our experience measuring particulates across a large portfolio for over 10 years, the constant striving to improve the result, and willingness to make sensible investments in filtration, has seen impressive advance in conditions for occupants on this measure.
If you are interested to learn more about how air quality can improve the cognitive function and therefore productivity of employees watch the video below, or download our whitepaper: How indoor air quality can improve the cognitive function and productivity of building occupants
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