Our method of assessing buildings’ energy efficiency can often be inaccurate and misleading. Would we do better by adopting the NABERS scheme used in Australia? asks Adam Branson
The UK’s current main method of assessing a building’s energy efficiency has significant problems. Energy Performance Certificates (EPCs) are often criticised for simply not being sufficiently accurate, partly due to the fact that it is incredibly easy to become a qualified assessor.
With commercial EPCs, it only takes a couple of weeks, while for domestic EPCs it is mere days. Rumours abound of domestic certificates being produced after no more than a cursory look at Google Earth.
A more fundamental charge is that, even when conducted assiduously by a competent assessor, EPCs do not truly reflect a building’s performance.
An EPC provides a view on how a building’s design suggests it could theoretically perform. What it doesn’t do is measure how a building actually performs.
The UK came close to adopting an in-use certification scheme under the coalition government. Display Energy Certificates (DECs) were due to come into play and would have been compulsory for all commercial property, but this was ditched at the 11th hour following a reported intervention by the then chancellor – and serial killer of green regulations – George Osborne.
Dec and nabers
However, DECs are compulsory for larger public buildings and the government is planning a consultation on introducing a new in-use scheme. The Better Buildings Partnership (BBP), a group of leading commercial property owners and developers focused on sustainability research and advocacy, is at an advanced stage in working up a proposal based on the Australian model. So, what might the new system look like?
The National Australian Built Environment Rating System, or NABERS for short, was introduced back in 1998. At first, it was a voluntary programme that simply looked at the in-use energy performance of existing office buildings. But the government wanted to do more to incentivise take-up.
‘The government helped to boost the uptake in the market by mandating a particular level of performance in their procurement,’ says Sonal Jain, sustainability director at property adviser JLL.
‘Unlike the UK, the government leases a lot more space in Australia, so they are a key tenant in the market. Investors started to respond and the government was soon followed by other occupiers who started to demand the use of the scheme.’
NABERS is based on a one to six-star rating, with one representing poor performance and six a highly performing building. In order to further increase its efficacy, the government gradually raised the level it would accept when procuring space. Again, the market followed its lead. ‘In some cases, they’re now saying that they will only take buildings that are five star plus,’ says Jain. ‘That is signalling to the market and in a sense moving the market to that level.’
If the building starts decreasing in performance, its rent goes down
And that, of course, has had an impact on rents. ‘If the building starts decreasing in performance, its rent goes down,’ says Bennetts Associates director Peter Fisher. ‘So, there is a strong motivation for landlords to maintain systems. It’s also about getting people to use buildings as well as they can be used. There hasn’t been a massive technological change. They’re using the same technology but they are using it better.’
By 2010, it was clear the market had accepted the system, and the government legislated to make the use of NABERS compulsory. From that point onwards, whenever a building was sold or leased, a NABERS rating had to be provided to the buyer or prospective occupier. Today, 78 per cent of offices in Australia have a rating with the proportion growing all the time as further property transactions take place.
Another important aspect of the scheme is that it distinguishes between the space and systems that are genuinely controlled by landlords and those that are controlled by tenants. That means the landlord-only score provides an objective measure of the energy efficiency regime over which they preside.
‘The base building is what the landlord has control over, so common parts and heating and cooling systems for the whole building, for example,’ says Richard Twinn, senior policy adviser and head of the Advancing Net Zero (ANZ) programme at the UK Green Building Council (UKGBC).
NABERS in numbers
The amount saved in energy bills by landlords and occupiers using the rating scheme since it began
The percentage of Australia’s office space with a NABERS rating
6 million tonnes
The amount of CO2 emissions saved in the last two decades through the office programme alone – enough to power 93,430 homes for one year
‘It removes the tenant areas from the score. It tells a tenant how good the landlord is rather than how good the building is on the basis of all these tenants who are doing lots of different things.’
Also vital to NABERS’ success is the use of what are called commitment agreement protocols. The protocols are legally binding contracts between developers and landlords and the supply chain. They establish the level of energy efficiency required on new-build and refurbishment projects and ensure that this is delivered.
‘They embed that in the contract of those delivering the buildings and deliver that performance in use,’ says BBP chief executive Sarah Ratcliffe.
The statistics associated with the scheme are impressive. Over the last 10 years, the average rating for properties has increased from a score of 3.3 to 4.5 out of 6, which translates into a 35 per cent improvement in energy efficiency. ‘The effect has been transformational,’ says Jain. At the same time, the scope of NABERS has grown significantly. The scheme now covers new buildings and includes data on water use and waste. It has also expanded to include other property sectors, such as hotels and apartment blocks.
Twinn isn’t surprised at NABERS’ impact. ‘In a lot of cases, buildings just aren’t being used properly,’ he says. ‘A recent study showed that a significant amount of office energy use comes from people not being able to turn the heating off in the summer, so they have the air conditioning going at the same time. Switching to in-use allows you to identify issues and then building managers come on the hook for how good the building is.’
Andrew Waugh, co-founder of architect Waugh Thistleton, calls NABERS ‘a brilliant scheme’ and believes it is driving a move towards more straightforward low-carbon design that works in practice.
As Glenn Murcutt said, man was not destined to live perpetually at 22 degrees
‘It is so much more effective than building regulations LEED or BREEAM,’ he says. ‘My suspicion is that we will quickly learn that, in our tepid climate, these ever increasingly complex building systems will be shown to be pointless in the face of taking a jacket off or putting a sweater on. As Glenn Murcutt said, man was not destined to live perpetually at 22 degrees.’
NABERS has also had a big impact in terms of the volume of landlords looking to upgrade their existing stock in order to remain competitive.
According to Jain, this has been largely due to the transparency the scheme provides. ‘It tells you how good or bad your building is in terms of energy and no one wants to have an average performance,’ she says.
The BBP has been looking at NABERS for some time, undertaking a literature and evidence-based review to see whether a similar scheme could work in the UK. Having established that it could, the next stage was to test it in practice.
‘We had a number of developers [245 Hammersmith Road, developed by Legal & General and designed by Sheppard Robson, pictured top] who put forward live office developments where we tested the key principles of the rating system to try and see how much of a performance gap there was [between theoretical and in-use performance],’ says Ratcliffe. ‘Those pilots demonstrated that not only was it possible to adopt this process in the UK but also that it was desperately needed.’
BBP recently signed a memorandum of understanding with NABERS, under which it has access to all the intellectual property it has developed. The partnership is also working up the rating system itself, as well as guidance documents to aid adoption.
These, Ratcliffe says, will be available for beta testing imminently. In addition, BPP has confirmed nine developments that will formally test the system. While their identities have not yet been released, the ‘pioneer’ developers include The Crown Estate, The Derwent Group, Great Portland Estate, Grosvenor, Landsec, Legal & General, Lendlease, Nuveen and Stanhope.
Initially, the British version of NABERS, known as Design for Performance (DfP), is targeting new-build development, but Ratcliffe says that it could be used for existing stock, provided the data is available to make the distinction between landlord and tenant areas.
For his part, Fisher believes that DfP will help architects to make the right sustainability calls early on in the design process and will increasingly begin to drive deep retrofit schemes, in line with the AJ’s ‘very timely’ RetroFirst campaign.
The combination of NABERS/DfP and net zero carbon will begin to push much more refurbishment work
He says: ‘Eventually I suspect the combination of NABERS/DfP and net zero carbon – in particular embodied carbon – will begin to push much more refurbishment work. The data shows the gains that can be made with simple interventions. At the most basic level this will be upgrading of services, in particular control systems. But it will evolve into deeper and more architectural refurbishment.
‘Similar concerns will also impact how we design new builds. These will be required to have much better durability and reuseability. The threat to property owners is that their stock will quickly be outdated.’
While NABERS does not account for whole-life carbon use, Twinn says that the UKGBC is working with BBP to see how its research on the embodied carbon half of the equation could line up with DfP. The BBP is also keenly aware of the need for training and quality assurance to underpin the new system.
Getting government buy-in for DfP would be the big win. That hasn’t happened yet, but Ratcliffe is cautiously optimistic. She is encouraged by the announcement of a consultation on an in-use rating system next year and says communication channels are open.
‘We have been keeping government informed and they are watching it,’ she says. ‘I can’t say what government is going to do but we have been engaging quite closely.’
Image top: Sheppard Robson’s 245 Hammersmith Road, developed by Legal & General, and one of the initial British pilot projects