Georgian Sash Windows: The Crown Jewel of London’s £138 Million Aberconway House
A residence near Hyde Park has recently become London’s most expensive home sold this year, fetching £138 million, making it the second-highest price ever for a home in the city. The purchaser is Adar Poonawalla, known as the “prince of vaccines” and CEO of Serum Institute of India, the world’s largest vaccine producer.
The house, Aberconway House in Mayfair, is a grade II-listed building boasting 23,000 sq ft of living space. It was acquired from Dominika Kulczyk, daughter of the late Jan Kulczyk, previously Poland’s wealthiest individual. Kulczyk had purchased the property for £57 million three years earlier.
Aberconway House, originally designed for industrialist Henry McLaren (later Lord Aberconway), is attributed to architect John Murray Easton, also known for designing the Royal Horticultural Hall in Westminster. The house features a neo-Georgian exterior, tall Georgian timber sash windows, and a steep pantiled roof. Inside, its 23,000 sq ft space includes vast rooms and polished interiors, with some design work by Edwardian architect Harold Peto.

A Short History of Georgian Sash Windows
Georgian sash windows are a distinct and iconic feature of British architecture, particularly prevalent during the Georgian era (1714-1830). Here are some key aspects:
1. Design: Georgian sash windows are typically made up of two framed window sashes that slide vertically. Early Georgian windows often had a “six over six” design, meaning six small panes of glass in each sash, held together by glazing bars. As the era progressed and glass technology improved, the number of panes decreased, leading to larger glass areas.
2. Material: The frames and sashes were traditionally made from wood, which was the predominant building material of the time. The glass was hand-blown, which gave it a slightly wavy appearance.
3. Functionality: The sliding mechanism of sash windows was not just aesthetic but also functional. It allowed for variable and controlled ventilation, as either the top or bottom sash (or both) could be opened.
4. Evolution: Throughout the Georgian period, the design of sash windows evolved. Early Georgian windows were flush with the exterior wall and had smaller panes. Mid-Georgian styles saw the windows set back from the façade, and by the late Georgian period, the windows often had only one or two panes per sash.
5. Symbol of Status: Large windows were a sign of wealth during the Georgian era. The Glass Tax and Window Tax, imposed in the 18th and 19th centuries, meant that only the affluent could afford homes with large or numerous windows.
6. Preservation and Restoration: Many Georgian buildings today, such as Aberconway House, are either listed or located in conservation areas, which means their original sash windows are often preserved or meticulously restored to maintain historical accuracy. This includes using traditional materials and building techniques.
7. Modern Adaptations: Modern versions of Georgian sash windows use double glazing and improved materials such as uPVC for better insulation and energy efficiency, while retaining the classic appearance.






