Rosewood London: How Vacuum Plumbing Enabled a Heritage-Sensitive Luxury Hotel Conversion

By any measure, the conversion of the former U.S. Embassy at Grosvenor Square into the Chancery Rosewood Hotel is a marquee project: a Grade-listed modernist icon reimagined for luxury hospitality in one of London’s most scrutinized urban contexts. The brief was familiar and paradoxical: preserve the building’s fabric while delivering contemporary comfort, quiet operation, and water efficiency without the destructive side effects that typically accompany plumbing upgrades in old structures. In other words: do everything a five-star hotel demands, without cutting historic slabs or building new gravity stacks. The plumbing concept was developed by Evac, the company behind many of the world’s vacuum systems in ships, and increasingly, in buildings.

The way through was not a clever workaround but a different physics. Instead of relying on falls and large-diameter pipework, the delivery team specified an Evac vacuum plumbing system that moves wastewater under negative pressure. The result was a quiet, efficient sanitary architecture routed horizontally at high level through ceiling voids, with small-bore mains and minimal risers, all converging on a basement vacuum plant. Heritage fabric stayed intact; the plan followed guest experience rather than stacks; commissioning proceeded floor by floor; and the hotel now operates with materially lower water use than a comparable gravity system.

 “In a listed building, the floor slab isn’t just structure; it’s history,” says Kiet Trieu, Global Marketing Manager at Evac. “Our brief was to protect that history and still deliver contemporary comfort with a believable program. Vacuum plumbing is what made those aims compatible.”

The retrofit trap: when gravity dictates design

Architects and developers know the trap. On paper, an adaptive-reuse scheme can look straightforward; in practice, gravity plumbing dictates where bathrooms sit, how many risers you must live with, and how much concrete you need to cut to achieve falls. In heritage fabric, each penetration triggers conservation protocols, latent-condition discovery, noise, dust, vibration, cost and risk that multiply across floors. The planning consequences are just as severe: risers steal sellable area and force awkward room modules; below-sewer spaces become expensive; long runs amplify acoustic concerns. In high-end hospitality, that’s a design, cost, and guest-experience problem.

Vacuum plumbing reframes the constraints. Because conveyance is pressure-driven rather than fall-driven, mains can run long distances at high level in small diameters (often 50–75 mm), threading structure and services with a fraction of the clash risk. Fixtures connect via vacuum interface units that open on command, moving discharge into the main. A centralized collection unit (in this case five Evac N°30 HQE units in the basement) creates the vacuum and discharges reliably to sewer with duty/standby redundancy. Complexity lives in a plant room, not in guest floors.

“The elegance is in what you don’t do,” says Trieu. “You don’t trench. You don’t cut slabs. You don’t proliferate risers. You route small, you route high, and you centralize the mechanics where they’re serviceable.”