Secondary Glazing on Historic Windows

Improving energy efficiency in historic buildings presents unique challenges, particularly within Grade I listed sites where alterations must be carefully controlled to protect heritage fabric. At Hampton Court Palace, Historic Royal Palaces identified heat loss through windows and draughts as one of the few areas where meaningful improvements could be made without compromising the building’s historic character.

To address this, Historic Royal Palaces explored solutions to reduce draughts while respecting the non-standard shapes and architectural significance of the palace’s windows. A specialist supplier and contractor were appointed to design and install bespoke secondary glazing tailored to each opening. The glazing was carefully specified to ensure it remained visually unobtrusive, did not damage the historic fabric of the building, and continued to allow access for maintenance and use.

The project demonstrates how sensitive, well-considered interventions can support sustainability goals even within highly protected heritage environments. While it is too early to assess long-term outcomes, the secondary glazing is expected to reduce heat loss, lower energy use, and support the more efficient operation of any future low-carbon heating systems, such as heat pumps.

This project also contributes to a growing culture of shared learning across South Kensington. By exchanging knowledge, data and practical experience between neighbouring institutions, organisations are able to test approaches, learn from each other’s successes and constraints, and apply proven solutions in their own contexts. This collaborative approach helps accelerate progress on carbon reduction and sustainability, particularly in complex settings such as historic buildings.