Ultra Slim Double Glazing for Listed Buildings & Conservation Areas

Telephone: 01535 603399
Email: info@sagarsglass.co.uk


Thin double glazing heritage units are suitable for conservation areas as well as period properties. Our highly skilled team of craftsmen manufacture thin double glazing units. Which are krypton filled and are delivered to multiple businesses nationwide.

Here at Heritage Glass UK by Sagars Glass Ltd, we offer The Sightline Range. The Sightline Range exceeds other market leading brands as they are slimline, very thin double glazed units. As our heritage double glazed units are so thin, they are perfect for Period Properties, Conservation Areas and Listed Buildings. 

We manufacture Heritage double glazed units with a 5.5 mm to 6 mm sight line, which fit into 7 mm rebates. The thinnest cavity we can manufacture is 4 mm giving a centre pane u value of 1.9.

Centre Pane U Values 

  • 4mm Cavity Krypton Filled 1.9
  • 6mm Cavity Krypton Filled 1.5
  • 8mm Cavity Krypton Filled 1.2
  • Improving EPC Rating.

Thin double glazing is the best solution for historic building restoration. In addition to this, we recommend thin double glazing for Grade I listed buildings and period properties. Planning departments also insist on our Heritage Units in some of the UK’s most historically sensitive areas.


We design our thin double glazing to be fit into timber and metal frames. We certainly design them so that they do not spoil the fine detail of the glazing bars. Our units are available in a wide range of thicknesses from 10 mm.  In addition to this they are also available in authentic glass types to suit the period.  We supply the Flexible Super Spacer Bars from Edgetech in black as standard, or optional white. Click for more details on this product


Values from 1.9 to 1.3.

Thin Double GlazingThin Double Glazing

Cut Heating Costs


We use U-values to measure insulation, the lower the figure the better the insulation. Heat lost through single glazed windows is in excess of 25%. Low E Double Glazed Units should reduce heating bills by around 20%.

Your Requirements

Whether you want your windows to reduce exterior noise or be self-cleaning. We can customize the glazing to meet your individual requirements.

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Also by Sagars Glass: Replacement Stove Glass