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A PASSIVHAUS WORLD FIRST EXETER CITY COUNCIL | SPACE & PLACE
Exeter City Council has been constructing buildings to Passivhaus standards since 2009, as it strives to become carbon net zero by 2030. Initially focused on Passivhaus council housing, in 2015 the council approached architectural firm SPACE & PLACE about the potential of building a leisure centre to Passivhaus standards. Nic Bryant of SPACE & PLACE designed the new centre and explains: “Opened in 2022, St Sidwell’s Point Leisure Centre is the first multizonal Passivhaus sports centre in the world. We worked very closely with the Passivhaus Institute in Germany – which has certified the building – and specialist external consultants, and in many cases have outperformed the targets we were set.” Low-energy building Located in the middle of the city and spread over five floors, St Sidwell’s features a 25m eight-lane competition pool, a 20m x 8m community pool, kids’ splash pool, 700sq m gym, two studios, kids’ play zone, café and spectator seating and a health spa with spa pool, three
heat experiences, four treatment rooms, a relaxation area and a roof terrace. It is therefore significantly larger than another nearby centre, which has a smaller gym, two studios, a six-lane 25m pool, small learner pool, small health suite – spa, sauna and lounge – and a couple of physio rooms. Yet where this smaller centre uses 4,000 megawatt hours (mWh) of energy over the course of a year, in year one St Sidwell’s used just 1,500 mWh. “Sub-metering of electricity use will ultimately allow energy consumption of specific areas, such as the swimming pools, to be better understood,” says Bryant. Exceeding targets He continues: “One of the key measures in Passivhaus design is the energy use per square metre of a building. For St Sidwell’s, the Passivhaus Institute set a target of 367 kWh per square metre per year (kWh/m²/year). In year one, we achieved 305 kWh/m²/year, outperforming the target by 20 per cent.”
At St Sidwell’s Point, tepid spaces are used to keep cold and warm spaces apart
Other important Passivhaus measures include air tightness, with the target for St Sidwell’s set at 0.45 cubic metres per hour – “how much air can be let out of the building every hour per square metre,” explains Bryant, adding: “Usually, a target of 3 cubic metres is challenging but achievable for builders.” Impressively, St Sidwell’s has achieved air tightness of just 0.2 cubic metres per hour. U-values – measured in W/m 2 K – are another Passivhaus measure and relate to thermal performance of a building. The lower the U-value, the better insulated the building. Current building regulations specify a U-value of 0.18W/ m 2 K, although older facilities commonly come in around 0.35W/m 2 K. At St Sidwell’s, the U-value of the pool roof is 0.09 W/m 2 k. Internal and external walls, doors and windows throughout the centre also perform strongly. “Excitingly, we and the Passivhaus Institute believe further efficiencies could be made, so the original mechanical engineer – now in-house at the council – is exploring further refinements,” says Bryant. Design innovation How have Passivhaus targets been achieved and surpassed at St Sidwell’s? Bryant explains: “We focused first on the exterior envelope of the building, making it super-insulated and
airtight and eliminating the ‘cold bridges’ that create cold spots. We also used triple-glazed windows throughout. “But what makes this a world first is our use of tepid spaces to keep cold and warm spaces apart. For example, a corridor between a warm pool and a cold gym to avoid loss of heat from one into the other. Walls between the thermal zones are also insulated, plus we’ve located facilities that are cold – such as the gym – on the north side of the building, and facilities that are warm, such as the pool, on the south side. “It’s a complex design process, because the space still has to work efficiently and flow just like any other leisure facility. Consumers shouldn’t notice a difference from this perspective.” He concludes: “More Passivhaus leisure centres are now in the pipeline, both through ourselves and other architects. Hopefully they will get better and better each time; certainly the Passivhaus Institute is always looking to refine and continually improve performance. “I also believe we must be cleverer in our choice of location, building leisure centres next to data centres, power stations, shops with lots of refrigeration units – anywhere that emits a lot of heat – and encouraging such businesses to open in any space adjacent to existing leisure centres. “There’s an opportunity here for savvy councils to be proactive in bringing free energy to their centres.”
The whole leisure centre has been designed to ensure warm facilities, such as the pool, are on the south side of the building
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STATE OF THE UK FITNESS INDUSTRY REPORT 2023 STATE OF THE UK SWIMMING INDUSTRY REPORT 2024
STATE OF THE UK FITNESS INDUSTRY REPORT 2023
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STATE OF THE UK SWIMMING INDUSTRY REPORT 2024
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