By Shauna Murray

Earlier this week, we held a webinar about the launch of NABERS UK; a simple reliable system for rating the energy performance of office buildings across England, Scotland and Northern Ireland.

The performance gap between design energy consumption and actual energy use has been widely publicised over recent years; NABERS UK and Design for Performance have been launched to bridge this gap.

During the webinar our panel of experts discussed what NABERS has achieved in Australia since its launch, what NABERS UK is, the rating process and the next steps you should take to make your existing workplace asset more sustainable.

During the Q&A there were lots of your questions we didn’t get to answer so we thought we’d address them here.

Q. When will NABERS UK be launched and do you know if it is likely to extend to Ireland?

A. NABERS UK was launched at the end of 2020 with publication of the methodology and rating scales, and now the next step will be for the scheme administrators Building Research Establishment (BRE) to open the accreditation process for assessors. We don’t yet have the confirmed timescales for that, but we expect that the first ratings might be issued next year.

We don’t currently know of any plans to extend the scheme to Ireland and this will be a question for BRE. NABERS UK is being positioned as complementary to BREEAM though, so it’s very possible that once the UK scheme is up and running they will explore demand for NABERS in similar markets like Ireland where BREEAM already has a strong presence.

Q. Due to the different seasonal profiles between the two countries, what are the envisaged challenges in the UK as opposed to Australia?

A. The NABERS UK scale has been set specifically for the UK based on benchmark data from across the UK, including buildings from Scotland and the north of England. What that means is that the rating scale adjustment will make it equally easy to achieve 5 stars in Glasgow as in Brighton-Hove (relatively speaking). Though a project in Glasgow may use more energy in an absolute sense, it’s not penalised by its location when the rating is calculated.

Based on the data in the NABERS UK rating tool technical report there are 5 buildings out of the 160-odd buildings in the benchmarking set that would be eligible for 6 star ratings.

Q. Can you talk a little about the governance of NABERS UK. Is it industry led, or a mix of industry and government? Presumably this is funded by assessment costs?

A. NABERS UK has been entirely industry-led so far, with the Better Buildings Partnership having driven the Design for Performance initiative and agreed with NABERS (Aus) to bring the scheme to the UK. BRE is now picking up the role of scheme administrator and intends for it to be self-sustaining through assessment fees.

Q. Do you have a feeling for the average additional modelling costs to accurately model ‘energy in use’ in the UK?

A. It depends on the complexity of the project as well as what the target rating is. In Australia, where there’s a strong track record of delivering buildings that achieve 4 and 5 star ratings the extent of simulation required is much less detailed than a UK project targeting the UK GBC Paris Proof 6 star NABERS UK target.

For complex buildings and those aiming for the highest levels of performance, simulation really needs to be embedded throughout the design process, with detailed modelling done at RIBA 2, RIBA 3, RIBA 4, updated through construction if the design or selections change and updated at RIBA 6 with commissioned figures and monitored against operational data for the first year in use. As a result, there can be significant difference in the simulation costs depending on the situation, but we’re always happy to sit down with project teams and put together costs schedules that reflect the individual project requirements.

Q. Is NABERS looking at schools/education facilities and do you know what the main differences may be if they do?

A. NABERS UK is not currently looking at the education sector and is starting out with just commercial offices. Schools and education facilities are already required to have Display Energy Certificates (DECs) which do a similar job to NABERS UK in terms of rating operational energy performance but at a whole building level (i.e. not broken down by areas of control). There is demand for the NABERS approach in offices because it is able to account for the landlord-tenant split in managing energy use. But a whole building approach offered by a DEC is often sufficient for education facilities because it is likely to be fully controlled by a single entity.

Q. Would it be better to get the EPC working better with more requirements for operational data than introducing a new rating scheme?

A. The EPC does need to be improved and the Government has said in the EPC Action Plan that it intends to improve the EPC using operational data. This will most likely be done by replacing some of the assumptions in the modelling with measured data about the performance of the building fabric and systems. But the EPC will still only cover the theoretical asset performance showing how it could perform if operated properly. NABERS UK and Display Energy Certificates on the other hand measure the actual performance based on how it is being used and operated.

So in the short term is likely that there will be both asset ratings (EPC) for regulatory purposes like minimum standards for rented properties and operational ratings (NABERS UK, DECs) which seek to drive ongoing improvements in how a building is being run.

Q. If a tenant isn’t worried about the landlords NABERS rating does it matter to the landlord (if the scheme targets landlords only)?

A. Under NABERS, the landlord is rated for only the landlord energy use: tenant lighting, small power etc. are not included in the landlord’s rating. Of course, the landlord energy includes air conditioning, and extended hours of operation will require additional energy, so NABERS uses the hours of operation data to make allowance for the landlord needing to operate the building for longer hours: effectively the benchmark is higher to match the increased hours, so the rating stays the same. What this means is that it’s still an equitable rating for the landlord, even if the tenant doesn’t care at all about saving energy.

Q. What percentage of offices in Australia have a NABERS rating?

A. It’s mandatory to declare the NABERS rating at point of sale or lease of more than 1,000m2. This means that most building owners just make sure they always have a valid NABERS rating in order to let any residual vacant space or to enable sale if a favourable purchase offer comes along. I’d estimate we’re looking at 85-90% of all commercial offices in Australia with a rating. If the owner opts into their rating being made publicly available these can be downloaded from the NABERS website.

If you would like more information, head over to our website or get in touch with our team:

Simon Wyatt, Sustainability Partner

E: s.wyatt@cundall.com

Jenn Elias, Senior Sustainability Engineer

E: j.elias@cundall.com

Richard Twinn, Principal Sustainability Consultant

E: r.twinn@cundall.com

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Shauna Murray, Sustainable Design

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