As differentiated from the Australian system, in which building codes and standards are modified and sometimes ignored by state governments, the EU establishes concrete objectives that feature heavy fines if their directive is followed.
In regards to NZEB compliance, the EU has permitted each member state to decide its own definition and benchmarks regarding how it will be achieved. It has not, however, surrendered control.
For example, the EU has advised that member nations in the Oceanic Zone, such as Ireland, should consume at most 50-60 kWh per square metres yearly of primary energy usage for housing, while generating 35 kWh per sqm yearly of on-site renewables.
For non-domestic users, the numbers are 85-100kWh per sqm yearly with 45 kWh per sqm per year of renewables.
Conversion rate or energy loss is accepted at a factor of 3.3. Therefore, two thirds of the original potential energy suffers a loss when converting to end use, or by the time it reaches your home.
The Irish residential cap of 50-60 kWh per sqm per annum equals to 15.5-18.2 kWh per sqm end use energy per annum.
In regards to the average Australian home, about 250 sqm, the yearly consumption of end use energy, should fall between 3875 kWh and 4550 kWh if compared to the Irish target.
In Australia, the nationwide standard yearly end use energy consumption is 5915 kWh, according to the ACIL Allen Consulting AER electricity distribution data.
This places Australians substantially above the markers advised by the EU.
In consideration of an Australian climate comparable to Ireland, Tasmania is a reasonable comparison. Tasmania’s energy usage in the typical residence is a huge 8813 kWh. Improvement is needed in this area.
The EU emphasises airtightness as a prime pathway to attaining NZEB. The TGL in Ireland—the Australian equivalent is Section J–maintains an upper limit of air surrendered through the building fabric of 5 cubic metres hourly per sqm per annum.
This is a reduction from the 7 cubic metres hourly per sqm established in 2011.
The NatHERS modelling tool, which establishes the standard for energy efficient homes, possesses an air tightness level between 12 and 15 air changes per hour. That’s above the 2005 level in Ireland.
And the EU directive will mandate that each new, single dwelling house and apartment must undergo a blower door test performed with pressurised and depressurised elements.
The test results for Irish homes undergoing blower door testing:
- 2005: 11.8 cubic metre hourly per sqm
- 2017: 3.66 cubic metre/h per sqm
- 2019: 2.85 cubic metre/h per sqm
This marked improvement was credited to a dedicated industry and a phased introduction.
Australians heat or cool their homes at least 50 per cent yearly. You are pouring energy and cash into your residence to keep a livable environment only to discover that 12-15 times per hour, most of that air is escaping.
This is the time for the Australian building industry to advance with a fabric first approach. They must guarantee that outer walls, ceilings and floors are expertly constructed with little leakage, to contain conditioned air and manage energy bills.
Evidence shows that houses performing in the 5m3/hr/m2 sector maintain enhanced interior air quality (substantially lowering smoke infiltration) and lower the risk of dampness and mould, considering that the mechanical system can ensure steady quality and humidity controlled air when the residence is closed.
And of course, damp air must be stopped from penetrating your building and rotting its materials with time.
The Australian building Industry must, as the old saying goes, build the change that it seeks. A few innovations can lead to healthier interior environments, lower energy bills, and a greener environment.