Case Study - The Biltmore Hotel, Mayfair

Client: The Biltmore Hotel
Location: Grosvenor Square, Mayfair, London
Project Type: Luxury hotel renovation, replacing Georgian sash windows

Nine Zero was engaged as part of the £60 million transformation of the former Millennium Hotel into The Biltmore Mayfair, now part of Hilton’s prestigious LXR Hotels & Resorts collection.

The project required the full replacement of over 200 timber sash windows within a historically significant Georgian building. We were tasked with retaining the architectural integrity of the façade while upgrading performance to meet modern hospitality standards.

Our team manufactured and supplied bespoke timber sash windows that preserved period detailing while delivering enhanced thermal performance, acoustic insulation, and long-term durability suitable for a five-star hotel environment.

Our work with developers

We support developers and commercial stakeholders on large-scale, heritage-sensitive projects. In this case, the scale of the refurbishment and the building’s high-profile location required precision manufacturing, reliable production scheduling, and strict adherence to architectural specifications.

Working alongside the wider project team, we manufactured to exact measurements, ensuring consistency and alignment with the overall refurbishment programme.

Working with developers

Scope of work

The project encompassed the manufacture and supply of:

Over 200 bespoke timber sash windows
Custom glazing configurations
Acoustic-enhanced glazing units
Period-accurate glazing bar detailing

Each window was crafted from sustainably sourced timber, combining traditional joinery methods with modern material technologies.

To meet the operational demands of a luxury hotel in central London, the windows incorporated:

High-performance double glazing
Specialist acoustic glass to reduce external noise
Durable timber frames engineered for longevity
Precision-balanced sash mechanisms for consistent performance

The final specification ensured the building retained its Georgian proportions externally, while internally achieving improved thermal efficiency and guest comfort.

Challenges and achievements

The scale of the project presented both technical and logistical challenges.

Manufacturing over 200 bespoke timber sash windows required absolute consistency in tolerances and detailing across the entire façade. The original Georgian sightlines and glazing bar proportions had to be preserved precisely, while modern acoustic and thermal performance standards were integrated into the design. Detailed CAD development was undertaken for every unit to ensure millimetre-accurate replication of the building’s original aesthetic. Production scheduling also had to align with the wider commercial redevelopment programme to support overall project timelines.

The result was a comprehensive façade upgrade that retained the building’s heritage character while delivering measurable improvements in energy efficiency and acoustic control.

Working on a large-scale refurbishment project?

Nine Zero manufactures bespoke timber windows and doors for heritage and high-specification projects.

Able to handle complex design briefs and large production volumes, our team delivers precision-manufactured timber solutions with clear timelines and dependable output capacity.

If you are planning a refurbishment or new-build development, speak to our team to discuss your specification requirements.

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