Hotels rank among the most energy-intensive buildings, operating around the clock to satisfy guests’ high expectations. Heating, ventilation and air conditioning, kitchens, swimming pools and laundry – all contribute to high operational emissions, which account for a large proportion of the hospitality sectors’ carbon emissions. These, in turn, make up 1% of the UK’s total carbon emissions.
Designers will be encouraged to pay more attention to the carbon intensity of hotels when the first version of the UK Net Zero Carbon Buildings Standard (UK NZCBS) is published later this year.
The cross-industry, voluntary standard aims to provide a single, consistent and science-based definition of what constitutes a ‘net zero carbon building’. It addresses operational and embodied carbon, and sets specific limits for both, to ensure a holistic approach to carbon reduction. To prove good performance, buildings must have 12 months of verified data, and there are rules on fossil fuels, renewables and refrigerants. A pilot version of the standard launched in September 2024, giving the industry the opportunity to test the feasibility of draft carbon limits for 13 building sectors, including hotels.
CIBSE Journal spoke to Mark Palmer, engineering director at Max Fordham, Ryan Horder and Juan Ferrari, both heads of hospitality & retail at Hoare Lea, and Joe Parr, performance engineer at Hoare Lea, to see how the standard might shape design strategies in the hotel sector.
Operational energy limits
Of the mandatory requirements in the standard, Horder identifies operational energy as the biggest challenge. ‘Maintaining continuous conditioning and hot water availability can conflict with energy-saving efforts,’ he says.
The UK NZCBS sets energy use intensity limits that decline steadily over time. For new-build hotels, the target is 85kWh.m–² in 2025, tightening to 45kWh.m–² by 2040. Retrofits face staged limits, from 120kWh.m–² in 2025 down to 55kWh.m–² by 2040.
The operational limits will force the sector to focus on maintaining good performance, according to Palmer. ‘It doesn’t matter how good your design is; if the building is not operated in the right way, you won’t achieve the standard,’ he says.
Parr believes that the early benchmarks for existing hotels are realistic. ‘The 2025 interim target of 180kWh.m–² per year aligns closely with the average energy use observed across Hoare Lea’s dataset of 146 hotels, of around 187kWh.m–² per year. But performance varies widely, from 50kWh.m–² per year to upwards of 500kWh.m–² per year depending on service intensity.’ He suggests the standard create more specific targets for hotel sub-categories, to reflect the diverse nature of the sector.
Technology – such as smart controls, heat recovery and efficient appliances – is also available to drive consumption figures down, but ‘consistent action and adoption across the sector is needed’, says Ferrari, who adds that indoor environmental quality should not be compromised when striving for energy efficiency. ‘Staff and guest wellbeing is linked to indoor environmental quality, so low carbon design should not forget to consider thermal comfort, air quality and lighting.’
Palmer believes there should be some recognition of the challenges of upgrading historical buildings. ‘Improving the building-fabric performance of listed buildings can be very limited. In those cases, it’s going to be near impossible to achieve the operational targets. On the other hand, the embodied carbon will be very low because they’ve been there for hundreds of years.’
To get to net zero, Hoare Lea recommends:Strategies for hotel decarbonisation
Embodied carbon limits
The UK NZCBS sets upfront embodied carbon limits that also tighten progressively: for new-build hotels, from 565kgCO₂e.m–² GIA in 2025 down to 160kgCO₂e.m–² GIA by 2040 and 40kgCO₂e.m–² GIA by 2050. For retrofits, the targets are lower still, recognising the carbon advantage of reuse.
Achieving these targets will be most challenging for new builds, says Palmer: ‘In buildings such as swimming pools, the embodied carbon is inherently high because of the types of finishes and the use of steel and concrete.’
Horder notes that embodied carbon in hotels is also influenced heavily by frequent refurbishments and fit-outs, especially in high-end establishments, adding substantially to life-cycle carbon.
Further reduction will have to come from improvement in the embodied carbon of the construction products and materials used, says Palmer.
Standardising low carbon materials and reuse strategies will be essential, adds Ferrari, encouraging life-cycle assessments early in design and prioritising circular economy principles.
Refrigerants and renewables
Some hotel typologies have inherent limits on onsite renewables, with tall buildings and small roof footprints restricting photovoltaic (PV) capacity, but Palmer sees the PV targets as ‘fairly achievable’, recognising footprint constraints while ensuring opportunities are maximised.
When it comes to refrigerants, the standard sets a global warming potential (GWP) limit of 677kgCO₂e.kg-1, aligned with R32 systems today. Palmer believes the target ‘could have been more ambitious’, but notes that it still allows variable refrigerant flow (VRF) systems, which have widely adopted R32, while encouraging a shift to lower-GWP options, such as R290 or CO₂.
Reliance on VRF and chillers will increase as fossil fuels are phased out, adds Parr, making leakage control and the selection of low-GWP refrigerants increasingly important. But Palmer notes that the industry is still too wedded to fossil fuels. ‘Too often, backup gas boilers are installed alongside heat pumps. The only way we’re not going to burn gas is to not have it on site,’ he says.
Hoare Lea is cautiously optimistic about the standard, and emphasises the importance of building stronger datasets for existing hotels to improve understanding of current performance levels and the practical limits of what can be achieved. Palmer, meanwhile, believes collaboration will be key: ‘Every aspect – the briefing, design, construction, quality control, handover and post-occupancy monitoring – has to be aligned. Everyone has to contribute to make it successful.’
