Double Glazed Sash Windows

Elegant Double Glazed Sash Windows – Period Charm with Modern Performance

At Cavendish & Cole, we believe you shouldn’t have to choose between the classic beauty of traditional sash windows and the energy efficiency of modern glazing. That’s why we specialise in double glazed sash windows that retain the elegance of original joinery—while delivering real improvements in comfort, insulation, and noise reduction.

Working across Sussex, Kent, and Surrey, we create and install bespoke timber sash windows, fitted with Slimlite double glazing and high-performance seals, tailored to suit both period properties and listed buildings.

The Perfect Balance of Form and Function

Using ultra-thin Slimlite units, our double glazed sash windows maintain the narrow sightlines and slender glazing bars characteristic of Georgian and Victorian sash windows, while offering significant thermal benefits. Whether you’re upgrading existing single glazing or replacing old sashes entirely, we ensure every detail—from the horn profile to the putty lines—is in keeping with your property’s style and age.

We offer both:

  1. New double glazed sash windows made to order in our joinery workshop
  2. Single to double glazed upgrades of your existing sash windows, preserving the original frames wherever possible

Why Choose Slimlite?

Slimlite glass is specifically designed for heritage properties and conservation areas, offering a discreet solution that meets modern expectations without altering the traditional aesthetic.

Benefits include:

  • Slim profile suitable for original sash frames
  • Enhanced energy efficiency and draught reduction
  • Improved acoustic insulation
  • Reduced condensation and maintenance
  • Available in Low-E, Argon-filled, or warm edge variants
We work closely with homeowners, architects, and conservation officers to ensure every installation meets planning requirements and enhances—not detracts from—your home’s character.

Seamless Upgrades – Without Compromise

If you love your original sash windows but want better insulation, our single to double glazed upgrade service could be the ideal solution. Where possible, we carefully remove the existing single glazing and replace it with Slimlite double glazing, retaining the original timberwork and enhancing the overall energy performance of the window.
  • This approach is perfect for:
  • Period properties where full window replacement is unnecessary or undesirable
  • Listed buildings, subject to local authority consent
  • Homeowners looking to reduce heat loss and draughts while preserving historical value
Double Glazed Sash Windows Brighton, Sussex, Kent and Surrey

Craftsmanship You Can Trust

Every double glazed sash window we create is made by hand in our Sussex joinery workshop, using premium timbers such as Accoya and durable hardwoods. All our fixtures, fittings, and sash cords are chosen for both performance and authenticity. From subtle draught-proofing to traditional putty glazing techniques, every element is designed to last—and to look right at home in your property.

Why Homeowners Choose Cavendish & Cole

  • Experts in double glazed sash windows for period homes
  • Specialists in Slimlite and heritage-approved glazing solutions
  • Single to double glazed upgrades to existing sash windows
  • Full compliance with listed building and planning permission requirements
  • Skilled, in-house installers and joiners
  • Trusted across Sussex, Kent, and Surrey
  • Warm, reliable service backed by years of experience

Ready to transform your home? Call us on 01273 282176 or email us here

Get in touch today for a free consultation. Let’s bring your vision to life—beautifully, traditionally, and made to last.
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