Since 1st November 2011, office owners and lessors have been required, in most cases, to obtain a Building Energy Efficiency Certificate (BEEC) before offering an office space of 2000m² or more for sale, lease or sublease.  On 1st July 2017, the disclosure threshold fell from 2000m² to 1000m². BEECs last for up to 12 months, expiring when either the NABERS Energy rating or the Tenancy Lighting Assessment on the BEEC expires.  

This page provides a summary of activity under the CBD Program, including a summary of the building energy efficiency data published through the Building Energy Efficiency Certificates.

Number of Building Energy Efficiency Certificates (BEECs)

The following chart and table show the number of BEECs issued per year. The numbers shown are the total number of certificates issued per financial year.  In some cases, a single building may be issued more than one certificate in a financial year: these are counted separately here.  Analysis of the number of unique buildings that participated in the program is presented in the next section. 

The first BEECs were not issued until 1st November 2011, so the number of BEECs issued in 2011-12 is less than for other years. The number of BEECs remained stable from 2012-13 to 2016-17.  There was a sharp increase in the number of BEECs issued in 2017-18 following the reduction of the mandatory disclosure threshold from 2,000m² to 1,000m² on 1st July 2017.  

CBD Program - number of BEEC's issued per year

Table: CBD Program - number of BEECs issued


Number of BEECs issued

2011-12 (from 1st November 2011)
















Number of Buildings Certified

The following chart and table show the number of buildings certified per financial year. The total number of buildings participating in the program each year is slightly lower than the number of BEECs issued, as some buildings receive more than one BEEC per year. This happens for a variety of reasons, such as when a NABERS rating is replaced or updated or when a space not covered by a current part-building Tenancy Lighting Assessment is offered for lease.

The table also shows the unique area of office space certified per year. Building area information was only collected from January 2015, so the area summary commences in 2015-16.  Note that this differs from the NABERS rated area in that it includes both occupied and vacant Net Lettable Area (NLA), whereas the NABERS rated area is based on occupied NLA.        



Website stats - Number of buildings participating in CBD



Number of unique buildings certified– new entrants

Number of unique buildings certified–previous program participants in earlier year(s)

Total number of unique buildings certified per FY

Area of unique buildings certified (m² NLA)

2011-12 (from 1/1/2011)








































Since the second year of the program in 2012-13, most of the certified buildings have previously participated in the program.  The proportion of repeat certifiers remained above 75% until 2017-18 when the disclosure threshold changed.  The high proportion of repeat certifiers reflects both the frequency at which disclosure obligations are triggered due to tenant or owner turnover, and the common practice of maintaining a current BEEC at all times.  Maintaining a current BEEC allows owners and lessors to act quickly if they need to put a building or space on the market.  Some finance providers also require building owners to maintain a current BEEC.

From 2013 to 2017 the average number of new program entrants was around 200 buildings per year.  These new entrants represent both new buildings and older buildings where a lease or sale process has triggered a disclosure obligation for the first time. In 2017-18 the number of new program entrants rose to over 300 buildings, when the mandatory disclosure threshold fell from 2,000m² to 1,000m². The number of repeat certifiers also rose, reflecting the greater likelihood of triggering a disclosure obligation in leasing operations due to the lower disclosure threshold.


NABERS Energy Ratings on BEECs

The NABERS Energy Rating on the BEEC is assessed on a scale of 0 to 6 stars. The NABERS Energy rating displayed on the BEEC is calculated without Greenpower, and is assessed on the basis of the base building energy, unless this is not available, in which case the whole building rating is displayed.  About 90% of BEECs use the base building rating.

The average NABERS Energy Rating on all BEECs issued has improved from 2.9 stars when the program was introduced in 2011-12 to 3.7 stars in 2017-18.  On an area-weighted basis where bigger buildings count more heavily than smaller buildingsthe average NABERS Energy rating has been over 4 stars since 2014-15.  Bigger buildings tend to receive better NABERS ratings than smaller buildings.  This occurs for a variety of reasons, including portfolio performance targets set by high-end institutional owners, better-resourced and more professional building management in larger buildings, and because larger buildings tend to be newer or more frequently refurbished.

The fastest improvement in the average NABERS Energy rating happened during the first few years that the program was in effect, when the owners of buildings that had not previously been rated acted quickly to capture energy efficiency opportunities that were “low-hanging fruit”. The slower improvement in average NABERS Energy rating during more recent years may also reflect the increased difficulty in moving from, say, 4.5 to 5 stars compared with 3.5 to 4 stars: a better-performing building needs to save a much greater proportion of its total emissions to achieve a given improvement in the NABERS Energy rating.

In 2017-18 the average NABERS Energy rating worsened for the first time since the introduction of the program.  This reflects the change in the threshold which saw the inclusion of a large number of smaller, poorer performing buildings for the first time in the program.

The following chart and table show the average NABERS Energy rating during each year since BEECs were first issued in 2011. The area-weighted average NABERS rating in the graph and table above has been calculated using the TLA area, since the whole building area was not collected on BEEC applications before 2015. 

Website stats - Average NABERS ratings on BEECs


Year Simple average NABERS ratings - all BEECs Area weighted average NABERS - all BEECs
2011-12 (from 1/11/11) 2.9 3.4
2012-13 3.3 3.7
2013-14 3.5 3.9
2014-15 3.7 4.1
2015-16 3.7 4.2
2017-18 3.7 4.1

Tenancy Lighting Assessments on BEECs

The Tenancy Lighting Assessment uses the "Nominal Lighting Power Density (NLPD)" to indicate the efficiency of lighting in office tenancies.  It is based on the type and number of lamps and luminaires installed in general office areas.  The NLPD is expressed in Watts per metre squared. A lower number indicates a more efficient installation. The NLPD is reported separately for each tenant suite or floor, whichever is the smaller. These separately reported areas are referred to as "functional spaces".  Tenancy Lighting assessments certified before 1st September 2016 were valid for twelve months.  Since 1st September 2016, tenancy lighting assessments have been valid for five years, following a recommendation in the 2015 CBD Review completed by Acil Allen.

The following chart and table shows the average NLPD in all functional spaces on all certified BEECs.

Website stats - Lighting efficiency on BEECs, average


Year Average lighting efficiency (NLPD, W/m²) Area-weighted average lighting efficiency (NLPD, W/m²) NLPD description
2011-12 (from 1 Nov 11) 14.3 13.1 Median
2012-13 13.1 11.7 Median
2013-14 12.6 11.3 Median
2014-15 11.8 10.5 Median
2015-16 11.3 10.0 Median
2016-17 10.8 9.6 Simple: median, Area-weighted: good
2017-18 10.8 9.3 Simple: median, Area-weighted: good

The energy efficiency of office lighting systems has improved dramatically since the program was introduced. The area-weighted average Nominal Lighting Power Density (NLPD) across all functional spaces certified under the program is now in the “good” category. 

The proportion of functional spaces where the lighting energy efficiency is rated “Excellent” has grown faster than any other category, with the proportion of “Good” spaces also growing from 2011-12 to 2016-17.  This reflects technological change due to the roll-out of LED technology, which has been readily available since the program was introduced in 2011-12. In 2017-18 the proportion of “Good” spaces fell for the first time, while the proportion of “Excellent” spaces continue to grow. The following chart shows the distribution of functional spaces certified in each calendar year.  Note that this is not weighted for the area of the functional spaces.

Website stats - Lighting efficiency on BEECs, distribution


Very poor Poor Median Good Excellent
2011-12 (from 1 Nov 11) 24% 24% 28% 13% 11%
2012-13 19% 21% 26% 17% 17%
2013-14 16% 20% 26% 18% 21%
2014-15 14% 18% 24% 20% 25%
2015-16 12% 15% 24% 20% 28%
2016-17 11% 13% 23% 22% 31%
2017-18 11% 13% 22% 20% 33%

The improvement in lighting efficiency happened fastest during the early years of the program.  The introduction of five-year TLA validity in September 2016 means TLAs are now much more rarely updated, creating a lag in the annual statistics.  It will not be until 2021-2022 that many TLAs issued in 2016-17 will be updated.  In addition, the lowered disclosure threshold from 1/7/2017 added a cohort of older, smaller buildings with less efficient lighting installations.

With over 50% of spaces now rated as either “good” or “excellent”, it is also noted that there is plenty of “head-room” at the high-performing end of the rating scale.  The deemed-to-satisfy efficiency requirement for new office lighting under the 2019 National Construction Code is proposed to be set at 4.5 W/m², which is well within the “Excellent” category as defined on the BEEC.