What really makes buildings efficient? A suite of surveys reveal remarkable results – and actionable items – that could easily up your star-rating, writes Dr Paul Bannister.

The technical issues associated with energy efficiency in the commercial office sector are relatively well established, though widespread application remains elusive thanks to a range of much discussed market failures.

The Low Energy High Rise (LEHR) project was established with the Warren Centre at the University of Sydney to seek methods to increase the uptake of energy and water efficiency. Rather than focusing on the market failures and barriers, however, we asked what was different about organisations or buildings apparently succeeding in the face of these problems.

In particular, we wanted to know what was the correlation between building technology, building management and building performance. So we undertook three surveys, one of base building technologies and management, one of tenancies on how they interact with the building, and another of building, property and asset managers uncovering their knowledge, attitudes, authorities and responsibilities.

In a world-first result, we have been able to demonstrate clear statistical evidence that certain factors really do correlate with efficient outcomes. If organisations address the major findings of the report, they can readily achieve an improvement of 1-1.5 NABERS stars. This translates to a 30 per cent improvement in sector performance, which in turn translates to a 1.2 per cent reduction in Australia’s national greenhouse emissions.

The scale of this impact is remarkable given the findings relate to management and low-end technical measures rather than major capital upgrades. Furthermore, an even higher impact would appear possible given the findings should be at least partly able to be generalised to other parts of the commercial buildings sector.

Rather than just the bare results, which are of limited assistance in informing actions and decisions, we developed a range of action-oriented recommendations based on the key findings and a degree of extrapolation.

Anyone can do it
Most building types can be operated at up to 3.5 stars, even if the underlying technology isn’t particularly efficient.

Buildings with variable air volume (VAV) air-handling units are capable of both the best and the worst performance, probably due to their reliance on control to produce efficient operation.

There was no significant difference between building grades, with all groups having both high and low performing examples.

While more recent buildings definitely perform better on average, all age groups have examples at the top and bottom of the scale.

In most cases, 4 stars are feasible without changing HVAC system type or reducing the building grade. This is important as it illustrates the strong potential for retrofit upgrades in the building stock rather than knock-down and rebuild.

The results also clearly indicate that economy cycles produce an improvement in building performance. Statistically, the difference in means between those with and without an economy cycle was 0.57 stars, though that has to be qualified to some extent as the survey sample was biased to temperate climates where the results are better than in tropical areas.

Incremental upgrades
Buildings perform better when managers undertake regular incremental upgrades and focus on eliminating older technologies.

There was strong support in the data for the proposition that sites that had conducted minor works in the past five years performed better on average than those that had not. For NABERS Energy, the effect was 0.6 stars while for NABERS Water the effect was 0.51 stars.

Interestingly, sites that had reported major upgrades did not show a significant performance benefit. This may be because such sites were coming from a very low base, or it may be that major upgrades genuinely don’t work. Anecdotal evidence suggests both may be true to some extent.

The recommendation to focus on elimination of older technologies arises from the aggregation of a number of questions relating to building technology, covering glazing, cooling technology, air-conditioning type, air-conditioning zoning and reheat, lamp technology and the control technology.

The aggregate outcome is not so much a measure of good technology as a measure of the degree to which the building fails to meet good practice. The result therefore indicates that a building with good basic infrastructure has a better chance of achieving a higher performance than a building that has significant impediments in design or equipment.

The elimination of such heritage technology can often be done incrementally, supporting the first half of the finding.

Reporting performance
Buildings that perform better tend to measure and report NABERS performance to tenants and the public, though this interpretation requires some care as there is a strong risk of reverse causality, in essence that buildings report because they perform well rather than the other way around.

To avoid this problem, the focus was placed on reporting to tenants separately from reporting to the public, as the former was considered to be less likely to be biased. The data were built from the combination of answers on whether the site held regular meetings with tenants and whether they reported energy efficiency performance.

As such, it indicates a level of positive engagement with tenants correlated with improved efficiency. The relationship shows a magnitude of 0.55 stars. For reference, the apparent impact of public reporting was approximately 0.5 stars.

Reasons to care
Better performers tend to provide the operators, maintenance staff and contractors with reason to care about the performance.
This finding is based on three separate statistical results.

The first, and possibly most controversial, is that buildings managed by in-house staff significantly outperform buildings managed by contractors.

The second finding was that staff-maintained buildings performed better than contractor-maintained buildings, which showed a remarkably large impact of 0.86 stars.

Finally, the provision of efficiency incentives to maintenance contractors correlates with better performance. It is noted, though, that all the respondents with such incentives actually applied penalties for non-performance rather than incentives for good performance.

While it is tempting on these findings to argue aggressively for in-sourcing of operation and maintenance, the depth of the sample and results are probably insufficient to draw such a strong conclusion. A less aggressive interpretation suggests that better results accrue when the operators and maintenance workers have a reason to care about performance, for whatever reason.

Strong managers, trained staff
Buildings that perform better have strong management leadership around energy or water efficiency, share common objectives and agendas for efficiency throughout the management chain, and retain efficiency savings in budgets.

Several results supported this finding. Sites where the main efficiency driver came from within the ownership group had better performance on average by 1.29 stars. Where multiple layers of management felt they had the ability to control energy efficiency, sites performed better on average by 0.88 stars.

There was also a weak but significant correlation between the number of years that savings were retained in budget and the NABERS performance. The longer, the better.

These factors together point strongly towards a basic conclusion that organisations that decide to do something about energy efficiency do genuinely go on to achieve those improvements.

Buildings also perform better when staff are given training in energy efficiency and are not overly conservative with efficiency technologies. Sites with an energy efficiency training program rated 0.51 stars higher than those without one. The rating was also better where building managers reported a higher level of skill in energy efficiency, though this was the only result where skills appeared to translate to performance.

Where the building manager only considered proven technology, the site was a generally poorer performer. Interestingly, the strongest such impact was that conservatism around water efficiency technologies had a 0.51 star impact on both the energy and water rating.

Conservatism regarding energy efficiency was not statistically significant, with water a better indicator of general conservatism possibly due to its more recent appearance as an issue.

Water and energy
A strong feature of the data was the cross-correlation between actions in energy and water. This implies there is a strong relationship between sites that successfully implement energy efficiency and those that successfully implement water efficiency.

This is further supported by the strong similarities between the findings for management and energy efficiency and those for management and water efficiency. This suggests that once the correct management structures are in place for one, the other follows.

The high level of cross-correlation between all these findings means it is not possible to treat the results additively. It is clear that an improvement of 1–1.5 stars is achieveable.

Dr Paul Bannister is MD of Exergy Australia.