4 expert articles on energy efficiency for London period sash windows, from heritage specialists with 15 years' experience.

• How to Cut Heating Bills by 30% Without Replacing Your Windows — Replacing original sash windows is not the only way to improve thermal efficiency. In many Victorian and Georgian properties, professional sash window…
• The Science of Secondary Glazing: How a 150mm Air Gap Cuts Heat Loss by 70% — For owners of period properties, improving window performance involves more than choosing the lowest U-value. Original sash windows contribute to a…
• Thermal Efficiency for Sash Windows: 10 Ways Your Period Property Isn't Holding Heat — Victorian and Georgian terraces are valued for their proportions, timber joinery and original architectural details. However, many were built before…
• Part L 2026 Vs Your Sash Windows: What Every London Homeowner Needs to Know — How the March 2026 Part L update affects Victorian and Georgian sash windows in London, including heritage exemptions.