Better Buildings Partnership – bridging the performance gap in UK offices

In terms of energy efficiency in UK buildings, a performance gap exists between what was intended at the design stage and what actually happens at the use stage. Better Buildings Partnership’s (BBP) Design for Performance (DfP) initiative has been designed to fix this.

This new approach being pushed by the BBP is predicated upon measurable performance outcomes and is based upon a 3-year review of the National Australian Built Environment Rating System (NABERS) Energy Rating & Commitment Agreement.  Sarah Ratcliffe, chair of the DfP executive board, and programme director at the BBP, explained the proposed change of approach like this:

The UK property industry desperately needs verification and disclosure of performance in use because, without these, the market cannot drive improvements in performance.

The problems pertaining to the current system are well-known:

  • Failing regulations
  • Current voluntary schemes check design intent, but seldom inspect whether this translates into better performing buildings 
  • Operational data is hard to get
  • Operational performance is not reported upon and is therefore invisible to investors, occupiers and the market in general

A picture has formed of a market that is operating blind, with no reliable way of ascertaining which buildings are performing well and which are not. In Australia, on the other hand, operational ratings are required, rather than the theoretical ones that form the basis of Energy Performance Certificates (EPCs), which were introduced into the UK following a European Union directive in 2007. A recent article about EPCs for ScienceDirect outlines a further aspect of the problem:

The performance gap, i.e. the difference between estimated and actual energy performance…, may be preventing adoption of bottom-up energy efficiency measures.

This intimates that EPCs may be not only doing the job they were created to do, but that 12 years on from their introduction, may actually be part of the problem. In that context, moving away from the current design-for-compliance model to one that can insert measurable performance outcomes at the brief stage makes sense.

What testing has taken place and is the plan achievable?

The DfP team and the BBP have run pilots and feasibility studies throughout the last 7 years. Initial findings clarified that NABERS could not be used accurately on existing schemes, as heating, ventilation and air conditioning (HVAC) energy use could not be considered discretely from tenants’ other energy uses. Therefore, DfP decided to concentrate on developing the scheme solely for new buildings. Following this, a 2015 feasibility study in conjunction with Australian experts and pilots undertaken in the last 2 years tested the scheme in actual office developments. This has convinced the DfP that a national scheme equivalent to NABERS has legs in the UK. Moreover, the myriad failings of the current design-for-compliance process were writ large in the pilot studies, as Robert Cohen, technical lead at DfP, states:

The current system of applying energy efficiency requirements based on a theoretical model – the results of which are never, and can never be, verified by measurements – is so fundamentally flawed it is remarkable it’s continued for so long.

Of course, the success of this project will not just be based on its technical capacity to measure accurately and deliver the required ratings: it will also need industry buy-in, upskilling, engagement, training and a recognised accreditation scheme. Furthermore, it is important to leave scope for future transformation, as alluded to by one expert in the sector: “developers need to be mindful not to lock in the energy profile of a building, as the future may bring new efficiency measures and a rise or fall in energy demands.”

How will the benefits be obtained?

The aim is to achieve total market transformation. A key part of that is advanced modelling, which is standard in Australia and not part of the thinking in the UK. Virtual running of buildings before construction utilising software common in Australia will enable this to be done quite easily. Advanced simulation requires HVAC modelling and gives a much greater level of precision, with defined control systems that are written into the draft operations and then used by the engineers when designing the controls. This means the real building ends up being controlled in much the same way as its virtual version did at the modelling stage.

NABERS began as a voluntary scheme, and became mandatory throughout the market via the size of asset requiring disclosure slowly shrinking over time. The DfP believes this can be achieved in the UK in a much shorter period of time; as well as clearly making sense for creating environmentally sounder buildings, it adds a layer to the engineers’ jobs that make them more exciting. This can be used by firms to attract the best people and increase their retention once they’re on board. A win-win, then, for assets, the environment and engineering? Here are some headline statistics from Australia:

  • 870 million dollars in energy bills saved by users since 1999
  • 6 million tonnes of CO2 emissions saved – enough to power 93,430 homes for 1 year (based on Office Energy ratings only)
  • 78 percent of Australia’s office space is rated with NABERS

There is a difference worth pointing out, though: NABERS is a government programme and as such has state backing and buy-in. The BBP, on the other hand, is an umbrella for a number of companies from the private sector, who all have very good reasons, both commercial and environmental, to push the adoption in the UK of an equivalent scheme to NABERS. What remains to be seen is whether it can obtain the necessary government buy-in to roll this out across the sector. Will the move from voluntary to mandatory be more difficult in the UK? Only time will tell.

Mainer Associates can assist with a variety of services aimed at closing the performance gap including, occupation phase energy modelling (TM54), soft landings procedures, Post Occupancy Evaluation, energy monitoring strategies and BREEAM In-Use. Please contact us at