‘Walking the talk’: building performance at 20 Fenchurch Street

At 20 Fenchurch Street, collaborative, data-led interventions have improved building performance dramatically. Andy Pearson looks at how proactive facilities management and occupier engagement have reaped huge energy savings

When it opened in 2014, 20 Fenchurch Street was hailed as one of the most sustainable buildings of its type in London, with a Breeam rating of Excellent.

Key to maintaining its sustainable operation has been the optimisation of the building’s energy performance. The landlord, H-Properties, gave this new impetus in 2022, when Savills was appointed as facilities manager. It immediately introduced new initiatives to optimise the operation of the building services systems.

One year later, and despite a 37% rise in occupancy, Savills’ interventions have resulted in a 22% reduction in water use, an 11% reduction in gas consumption and a 5% reduction in electricity use.

This impressive achievement was recognised at this year’s CIBSE Building Performance Awards (BPA), where the scheme won the Facilities Management (FM) category. The award judges said Savills’ entry showed ‘how a proactive approach to FM can yield dividends over a relatively short timeframe’.

Nicknamed ‘the Walkie Talkie’, 20 Fenchurch Street is one of London’s most iconic buildings. Its distinctive design, by Rafael Viñoly Architects, is the result of the increasing size of its floor plates, from the ground floor lobby all the way up to the transparent, three-level Sky Garden and observation deck that crown the 160m-high tower. Between the double-height ground-floor lobby and the rooftop public garden, there are 32 levels of Grade A office space.

As soon as it was appointed, Savills adopted a collaborative approach to working with its service providers. It moved its office from the 23rd floor down to the basement, to be close to their offices in order to improve collaboration and communication.

Cooperation was further enhanced through the introduction of early morning team huddles, led by Savills’ team leaders, where the day’s priorities were outlined and actions requiring a more coordinated cross-team approach were identified.

Some tenants are driven to save energy by competition against their peer occupiers

In 2023, the newly appointed FM team worked on ‘good behaviours’ to foster a cultural change within all service provider teams and engage with occupiers. This ‘environmental stewardship’ ethos helped to promote no-cost solutions to lighting and HVAC energy waste simply by optimising timeclocks. This delivered a meaningful saving against 2022’s energy consumption, despite a significant increase in ‘return to the office’ occupancy (36.6%).

Additionally, thanks to its ‘digital led maintenance’ initiative, the team was able to use data to identify water-saving opportunities, resulting in a near 22% decrease on the consumption in 2022.

As well as the daily huddle, Savills introduced weekly service provider meetings and monthly review meetings, at which service providers were expected to present their key performance indicators (KPIs), discuss their performance, and set future objectives to further improve their performance.

To help drive energy savings and optimise the building’s operation, Savills introduced a variety of measures, including applying a low-temperature hot water (LTHW) ‘hold off’ – to make sure LTHW pumps do not operate when heating is not required during the warmer months – and adjusting plant running times, to better reflect changes in occupancy trends.

Savills also set out to optimise the valve-exercising schedules for the two cooling and two heating plate heat exchangers on each floor (see panel, ‘Smoothing energy demand by reducing valve exercise’). Occupiers were encouraged to reduce the number of hours the heat exchangers were in operation to reflect their occupancy. Sean Harlow MCIBSE, Savills’ head of engineering at 20 Fenchurch Street, says: ‘95% of occupiers have reduced heat exchanger operational hours by at least one hour per day and some have gone much further.’

Smoothing energy demand by reducing valve exercise

Energy data analysis by the energy management team, using the smart building platform, found an energy spike produced by the chillers and boilers, and their pumping systems, at 02:00 hours every night. Subsequent investigations found the cause to be the plate heat exchanger valve-exercise regime.

There are two cooling and two heating plate heat exchangers serving each of the tenant floors. Valve exercising is the planned, routine operation of the LTHW and chilled water valves serving the heat exchangers, to ensure they continue to function correctly.

The regime involves opening and closing valves through a full cycle, then returning them to their normal position. This stops them from becoming stuck because of inactivity and prevents costly repairs. The heat exchanger valves were scheduled by the BMS to exercise at 02:00 hours every night. However, the process of opening and closing the valves caused the central plant to operate, which resulted in the night-time energy-use spike.

To solve the issue, the BMS engineer was able to reduce the frequency of the regime so that the valves now exercise once a week. In addition, Savills implemented a central system hold to prevent the chillers starting up and boilers firing while water was circulated.

‘The spikes were effectively reduced by 87% by reducing the exercise frequency to once a week, and then the plant “inhibit” helped smooth energy demand,’ says Sean Harlow, Savills head of engineering at 20 Fenchurch Street.

The Savills team engaged occupiers to also recommission the lighting controls system throughout the landmark building, to ensure lighting on the majority of tenant floors is turned off outside of business hours. In addition, it encouraged them to repair faults and recommission elements of the lighting control, including presence detection, to turn lights off at night and in unoccupied spaces during office hours. As a result of this initiative, Savills saved 3,780kWh of electricity over 13 months, which helped win it the Air Quality and Climate Action Award at the Clean City Awards.

One of Savills’ most significant interventions was to introduce comprehensive energy monitoring, by employing Atrius, a cloud-based smart building management platform. More than 700 sub-meters now collect data, which is analysed and displayed via the online platform. This has enabled occupiers to have access to live consumption data.

The energy management system is accessible by tenants to monitor their energy consumption and check for anomalies in energy use. ‘The system’s main aim is to provide occupiers with energy-use dashboards and to identify energy-use trends, with the greater aim that education on the cause of these trends would lead to good environmental behaviours,’ explains Harlow.

The smart building platform is also used by Savills’ external energy consultant EO team. It uses the energy data to identify further energy-saving opportunities and address anomalies in thermal energy consumption, which are discussed in its monthly meetings with the facilities management team.

H-Properties appointed Aecom for the property’s Net Zero Pathway initiative, working with Savills’ UK engineering team to support an aligned planned maintenance programme report and undertake a separate energy audit.

‘Aecom and other partners have supported us in finding issues and in resolving these,’ Harlow says. ‘For example, during the Net Zero Pathway works, we identified that pumping energies were not consistent and determined that a recommissioning exercise was required. This was done by the onsite engineering team and resulted in an energy saving of up to 30%.’

At the same time, Savills started to build strong relationships with the occupants of the office floors. To encourage this association, Savills developed its ‘Energy Strava’ tool – a similar concept to the website used by athletes to compare their performance.

The tool anonymously ranks each tenant’s energy performance relative to how others are doing, with the intention of motivating them to outperform their neighbours. Harlow describes it as ‘the coolest engagement tool deployed’. While some tenants want to save energy for environmental or economic reasons, he adds, some ‘are driven by competition against their peer occupiers’.

It’s a tool that appears to be highly effective; Savills reports that more than 50% of tenants have requested its support to help them reduce their energy consumption to improve their Energy Strava ranking.

Harlow cites the example of one occupier who came bottom in the ranking. It engaged with Savills to try to understand the causes of its poor performance and the steps it could take to improve. ‘We helped them on their energy journey,’ he says.

He gives another example of a well-performing tenant that was ‘floating’ between second and fourth in the energy ranking. ‘They proactively made adjustments to lighting and HVAC controls to make the necessary energy savings to reach the No 1 spot,’ he says.

Comprehensive energy monitoring has been introduced at 20 Fenchurch Street, where more than 700 sub-meters collect data

In the same vein, the ‘Scavenger Hunt’ is an occupier-specific questionnaire introduced by Savills to increase energy engagement with tenants. Before a tenant takes up occupancy, Savills provides guidance to help occupiers recognise and adopt environmentally friendly fit-out practices. During their subsequent occupancy, Savills will work with the tenants to help them minimise energy use.

‘Engagement has to be two-way, so I created a “Scavenger Hunt” for occupiers to answer questions about their HVAC system and its operation,’ explains Harlow.

The questionnaire is followed up with a one to one with occupiers, after which their answers are analysed in the context of data from the building management system (BMS). ‘We are able to have an informed discussion, which allows us to work with the tenant to optimise their HVAC services to improve their operation and provide better comfort and wellness,’ says Harlow.

More recent interventions by Savills to save tenants energy include adding a ventilation night purge (between 2am and 5am) to the tenant floors when internal temperatures remain high. The primary ventilation system extracts warm air from high level on each floor, which is subsequently discharged to the outside. Supply air dampers open to allow cooler air to be drawn passively onto the floors. The initiative works well and, thanks to the BMS modifications, the system can be enhanced by bringing the supply air fans into operation.

‘The key benefit is that the on-floor temperatures are lower at the start of the day, so there is a lower chilled water energy demand,’ explains Harlow.

Another modification that is used when it is warm outside is an exterior air temperature interlock to hold off the heating system. Heat captured from the ceiling voids is used to meet the heating demand of occupiers instead. ‘The outside air temperature determines the operation of this optimisation rule,’ says Harlow.

Since its BPA submission, Savills has continued its work to improve the building’s energy performance. As a result, gas consumption has reduced by 37% compared with the previous 12 months, which – with Degree Day analysis – equates to a 42% saving. Electricity use has reduced by a further 4%, when compared with the previous 12 months, and landlord energy has reduced by 16.6%.