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Reaching net zero: Don’t let your building get left behind

Article by Chris Newman, Zero Carbon Design Manager, Mitsubishi Electric

Reaching net zero: Don’t let your building get left behind
Chris Newman

There is a growing body of legislation focused on reducing energy consumption and decarbonising heating in the UK’s commercial building stock – across offices, retail space, universities and more. As a result, existing buildings are now at risk of becoming ‘stranded assets’ if they fall short of meeting these standards both now and in the future.

Some building owners are already facing the up to meeting higher standards for Energy Performance Certificates (EPCs) and switching from gas boilers to renewable heat pumps. Those buildings that don’t will fall further behind environmental requirements every year that upgrades aren’t made – and eventually they will become un-lettable and essentially stranded assets for building owners. For example, 1.4 BN square feet of retail space may be unlettable by 2030 if EPC ratings aren’t improved in the sector.

There is a clear business incentive to decarbonise too. Interest in sustainable buildings is reflected in property investment – with the number of green loans growing massively as investors seek out ‘future-proofed’ built assets.

Therefore, it is vital that building owners and managers develop a stronger understanding of net zero goals and how to adapt spaces in line with upcoming regulatory changes. One important aspect to consider is rethinking the technologies used to heat, cool and ventilate them.

The challenge of defining ‘net zero carbon’

Buildings are currently responsible for 20% of all carbon emissions across the UK, so decarbonising them is a big step on the road to net zero. The Government is supporting this transition, first by setting the net zero goal for 2050 back in 2019, and more recently by introducing Part L of the Building Regulations, which establishes higher standards for energy efficiency for new and existing buildings. A wider consultation on the importance of reducing embodied carbon is also taking place following the rejection of Part Z late last year.

But while these regulations are helping to improve the energy efficiency of the built environment, they don’t provide clarity on the issue of what ‘net zero buildings’ actually are, how they should perform or an agreed standard to denote them. This means while there is a destination for net zero, there is no map for builders, architects, consultants or contractors to get there.

As a result, the UK Net Zero Carbon Building Standard, developed by a group of leading industry bodies including CIBSE and the Carbon Trust, is aiming to establish a set of criteria for measuring net zero carbon performance, such as energy use and embodied carbon.

In the future, this should help building owners and managers to evidence that their buildings are built and operating in line with climate science and will enable all stakeholders to differentiate between buildings that are net zero, and those that aren’t.

Finding ways to boost efficiency and cut carbon

In the absence of a clear map for achieving net zero, there are still areas that building owners can focus on now. Boosting energy efficiency and cutting embodied and operational carbon emissions can both help to keep built assets operational and meeting increasingly strict regulations. However, it is also important to consider systems that will deliver on occupant comfort and maintain a healthy indoor environment when retrofitting or refurbishing your building.

With energy consumption responsible for 40% of greenhouse gas emissions worldwide, energy use is an essential area for building owners and managers to consider. The Net Zero Carbon Buildings Standard also estimates that non-domestic buildings will have to achieve a 59% reduction in energy use to reach net zero, meaning lowering energy use will be vital to reaching this goal.

One way to measure a building’s energy use is by using Energy Use Intensity (EUI), which can help identify which areas are using the most energy, as well as the amount of energy a building is using overall. This can help identify any areas requiring improvement, as well as informing the type of equipment chosen to install in each space.

It is also important to measure embodied carbon – not just operational carbon. This includes the carbon impact of the wider supply chain – everything from using HVAC equipment, to the carbon impact of its manufacture, maintenance, repair, transport and even disposal at end of life. When it comes to new buildings, the embodied carbon can be significantly reduced by focusing on materials used, how things are transported to site, and the impact of the products installed in the building. For existing buildings, little can be done to alter the embodied carbon created during construction – but re-using existing buildings through refurbishment is a better alternative than demolish-and-rebuild.

A review of the HVAC systems operating in a building is also an important starting point for boosting efficiency. For example, by checking what refrigerants are used in the existing air conditioning system, whether heat recovery is being used in ventilation systems, and even the service and maintenance regimes. This can help inform the kind of equipment chosen for the building in future, and ensure that existing kit is running effectively.

Opting for the right technology

After assessing and understanding the current state of building equipment and layout, the next step is finding equipment that lowers carbon and energy use and meets a building’s specific requirements.

Where possible, it’s important to replace current equipment with lower-carbon alternatives, including lower-GWP (Global Warming Potential) refrigerants like R32. These can help lower the amount of energy used and help to protect a building against changing F-Gas regulations committing to the phase down of HFCs (hydroflauorocarbons) by 2030.

Switching to more renewable forms of heating can also help to improve energy efficiency in a building. Heat pumps, for example, are able to provide heating and hot water for a wide range of building applications, while also being around 300-400% more efficient to run than a gas boiler.

Ambient heat loop networks, which make use of heat extracted from cooling areas to deliver space and water heating in nearby spaces, are also ideal for mixed-use buildings with cafes, gyms, offices and apartments located alongside each other.

It’s also important to look at the amount of energy these systems use, with an energy management system, so that energy can be monitored and trends for improvement identified. With an ongoing maintenance programme focused on efficient operation, it’s also possible to highlight where efficiencies can be improved and how efficiency targets can be met.

By assessing carbon and energy output, and adopting lower-carbon technologies, building owners and managers can be sure that their buildings are moving towards net zero. Even in the absence of a clear formula to identify ‘net zero’ buildings, this will help ensure the UK’s building stock doesn’t end up as ‘stranded assets’ in the future.

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