Reducing the energy used by commercial buildings remains a major challenge for the property sector. New government data suggests that making meaningful progress may depend as much on where we focus our efforts as the measures we ultimately implement.

The latest Non-Domestic National Energy Efficiency Data Framework (ND-NEED), published by the Department for Energy Security and Net Zero, provides a detailed picture of metered energy consumption across non-domestic buildings in England and Wales.

There are positive signs. Total electricity consumption fell by almost 2% in 2024 to 120 TWh, following a fall of around 3% the previous year. Weather-corrected gas consumption also fell by 1% to 151 TWh.

But the more useful finding for commercial property owners may be where that energy is being consumed.

A small proportion of buildings consumes mostof the energy

Among buildings where floor area information is available, those larger than 1,000m² represent only around 7% of the non-domestic building stock, yet account for approximately 61% of electricity consumption and 70% of gas consumption.

With around 1.77 million non-domestic buildings in England and Wales, improving the efficiency of the entire estate is a huge undertaking. For individual property owners and organisations managing portfolios, however, the figures point towards a more manageable question: which buildings should we tackle first?

This is where energy reduction needs to move beyond broad targets and become an asset-level exercise. The highest-consuming building in an estate is not necessarily the least efficient. It may simply be larger, more intensively occupied or have greater operational demands. Equally, an apparently efficient building may still contain straightforward opportunities to reduce consumption.

The important thing is to establish what is driving demand before deciding what to do about it.

That means looking beyond annual energy bills. Consumption profiles, occupancy patterns, operating hours, HVAC performance, controls, plant condition and planned replacement cycles can all help build a much clearer picture of where intervention will make a difference.

Different buildings need different answers

The ND-NEED data reinforces this point because energy usevaries significantly between sectors.

Hospitality buildings have the highest median energy intensity for both electricity and gas, followed by shops and healthcare buildings. Factories, meanwhile, account for 28% of non-domestic electricity consumption and 42% of gas consumption, making them the highest-consuming building category outside the report's broad 'Other' classification.

Those differences make a standard approach difficult. A hotel operating around the clock has very different requirements from an office occupied five days a week. Manufacturing facilities may have substantial process loads, while warehouses, healthcare facilities and retail environments each have their own patterns of use. Even two apparently similar office buildings can behave very differently depending on occupancy, plant, controls and how they are managed.

So, rather than beginning with a particular technology or predetermined list of improvements, the starting point should be the building itself.

Look at what you already have before deciding what you need

This is particularly important given the age of the UK'snon-domestic building stock. Of buildings with a known construction date, 63%were built before 1970, including 28% constructed before 1900.

Age does not automatically mean poor performance. Older buildings can perform extremely well when they have been sensitively upgraded and effectively operated, while newer buildings can still waste significant amounts of energy. However, much of the commercial estate was designed long before today's expectations around energy efficiency, controls and decarbonisation. Improving those buildings will be central to reducing overall demand.

That does not necessarily mean starting again.

We regularly see opportunities within existing M&E systems that can be addressed before wholesale replacement is considered. Plant may be operating for longer than necessary; heating and cooling can be working against each other; set points and time schedules may no longer match occupancy; pumps and fans can continue running at fixed speeds when demand varies considerably throughout the day.

Buildings change too. Spaces are refurbished, occupancy rises or falls and working patterns alter, but the services supporting them are not always reviewed at the same time.

Finding and correcting those issues can sometimes produce meaningful savings without significant capital expenditure. Where investment is required, understanding the existing system first also helps ensure that money is directed towards the right intervention.

Turn estate data into an investment plan

For organisations managing multiple buildings, this is particularly relevant. Rather than trying to improve every asset simultaneously, owners can use energy and building data to create a hierarchy of opportunity.

Which buildings account for the greatest proportion of the estate's consumption? Is that level of demand justified by their size and use? Which have ageing or inefficient plant? Where are controls limiting performance? Which assets already have refurbishment or replacement projects planned?

Overlaying those factors can help identify where investment is likely to achieve the greatest benefit. It can also reveal opportunities to combine projects. If a chiller, boiler or air-handling unit is approaching the end of its useful life, for example, that planned replacement can become part of a wider review of demand, controls and system design rather than simply replacing one item of plant with another.

That is potentially a much more effective use of capital than selecting technologies first and then looking for somewhere to deploy them.

Start with the opportunity, not the solution

The ND-NEED figures provide a useful national picture, but their real value is in prompting better questions at building and estate level.

Commercial property owners are being asked to reduce energy consumption and carbon emissions while managing ageing assets, maintaining comfortable environments and making limited capital budgets work harder. There will rarely be one intervention that solves all of those challenges.

What owners can do is establish where their greatest energy demand sits, understand what is driving it and prioritise the buildings where operational changes, M&E improvements or planned investment can have the greatest effect.

The data shows that energy demand is highly concentrated. For individual estates, the pattern may be different, but the principle remains useful: before deciding what to spend, understand where the biggest opportunity lies.

At Green Building Design Consultants, we work with clients to assess existing buildings and M&E systems, understand energy performance and identify practical opportunities for improvement. If you are considering how to prioritise investment across a building or wider estate, speak to our team about where to start.

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