Slim double glazed units supplier

Double Glazed Units

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. Slenderpane has been providing slim double glazed units since 2011 and as a leading UK provider take the industry standards extremely seriously. Having worked with Edgetech, who themselves are the leading manufacturer of warm edge technology, our Heritage Sealed Units have been tested and achieved full accreditation in compliance with EN1279 parts 2 & 3.

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. 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.

Sighlines for slim double glazed units


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.

U 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.

BSI Certification

Slenderpane insulated glass units meet BSI standard BS EN 1279-3:2002.

Get A Glazing Quick Quote - TRADE ONLY

Complete and send our online "Quick Quote Form" and we will get back to you within 24 hours.

Warm Edge Superspacers & Sealant

We 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

Mr Hothersall, Somerset

"I thought I would get in touch following installation of your glass by Chris of Sash Window Doctor, Portland, Devon. We never expected huge differences in temperature with this type of slim glazed units so only gave Chris a couple of windows to see if your website claims stand up. The honest answer is yes!"

"I’ve been very impressed so far and with a 7mm sight line, your 10 year guarantee it gives me confidence, so much so I’ve asked him to do several more windows. I’m sure you will look after him, and I’m grateful that both he and your company exist to keep older buildings going and not simply rip out perfectly good wooden frames etc. well done!"

David George-Powell, Buckinghamshire

"I have received the units . Just like to say I am very pleased with the quality of your units they are very well made."

"I have seen a lot of units , I have been around the glass industry all my life. My dad owned two glass shops and was in the business for 61 years."

"The packing crate was a bit damaged but I think there is no damage . We used to put a glass fragile sticker on , the delivery drivers seem to understand that better. He thought it was a machine. Thanks for your speedy service hope to deal with you in the future."

Bobby, Berkshire

"Thank you for the glass that was delivered today. Can I just say your service is amazing and the packaging ezxeptional. Please pass my thanks to Ralph also."

Social Media

Opening Hours

Monday - Thursday: 8.30am - 5.00pm
Friday: 8.30am - 4.00pm
Saturday, Sunday & Bank Holidays: Closed

Slenderpane's Workshop Showroom visits for Trade customers are by appointment only.

We are proud to be sponsors of the Florence Nightingale Hospice Charity

Florence Nightingale Hospice Charity

Contact Form