Double Glazed Units

Slim Double Glazed Units For Conservation & Listed BuildingsOur Products

Due to the fact that Slenderpane only make very neat thin double glazed units, we are totally focused on providing what we know you want.

High specification, high performance, top quality units.

Our units include bespoke leaded glazed units – please see examples.

To achieve this we use only the best components including thermally efficient glass, the heavy and inert krypton and argon gases, warm edge superspacers and the most suitable butyl hotmelt sealant.

Slenderpanes quality endorsement for slim double glazed units

For a quote please complete our Quick Quote form.

Our paperwork and computer system show the glass weight as a combined total. However please use the calculator link to get the individual item weights.


Slenderpane’s slimline (slimlite) units are designed to give the appearance of single glazing but with all the benefits of thermal insulation and reductions in condensation and sound transference that normal double glazed units provide.

This fact has contributed to an increasing number of conservation projects across the UK receiving planning permission to use slimline units thereby addressing the balance of aesthetics versus energy efficiency.

Slim Double Glazing SuppliersSightlines

We recommend a minimum 8.5mm rebate to allow for a 7mm perimeter seal on the units (see link showing glazing bar) If you only have a 7mm rebate, we also offer our Heritage warm edge spacer that has a sight line of 6mm.


Krypton gas is used as it has a greater density than other gases suxch as argon. They make a major contribution to thermal insulation and assist with noise reduction.

Ultra thin double glazed unitsU Values

Dependant on the glass, size of cavity and which of the inert gases are used, thermal efficient U values of between 1.9 and 0.9 are achieved, assisting with meeting new Part L regulations for whole window values.

Our price list details these U values according to the specification required and is available on request.

Warm Edge Superspacers & Sealant

Handmade glazed unitsWe use the most up to date and technologically advanced warm edge super spacers that also assist in the achievement of the above U values, together with a butyl hotmelt sealant that has excellent adhesion properties to both glass and spacer bar and a very low moisture vapour transmission rate.

Spacers are available in black, grey or white. However we would recommend black as, in our opinion, the resulting effect is that it is very difficult to detect that it is not a single pane of glass as illustrated in this photograph.


All Slenderpane units come with a warranty and now most of our units have a 10 year warranty. For full details please check our Warranty Information.

Slenderpane Warranty

BSI Certification

Slenderpane insulated glass units meet BSI standard BS EN 1279-3:2002. Please view the attached certificates for the Insulated Glass Units and Gas Specification.

Slenderpane Brochure

Please download our brochure.Slenderpane Brochure