What is Vacuum Double Glazing?

Here we look at Vacuum Glazing and its unique advantages


It is a common misunderstanding that in all double glazed units there is a vacuum between the panes. They are in fact full of either normal air in the case of standard low cost units, or inert gases, most commonly Argon, in the more modern, more efficient slim units.

It’s the air or gas molecules that enable heat energy to be transferred from one pane to another so using a gas with heavier particles basically slows down heat transfer in the unit and increases heat retention.

But what if you could take out the air or gas completely? This is what happens with Vacuum Glazing units such as Pilkington Spacia TM or LandVac TM .  Extracting the air from between the panes creates a very exciting and energy efficient product.

The main advantage is almost unbelievable heat insulation with figures normally around the 1.0 W/M2. K down to 0.5 W/M2.K in a unit that is barely thicker than a standard piece of single glazing. This makes Vacuum Glazing ideal for retro-glazing into existing period windows with little or no on-site carpentry work or glazing rebate modification required.

Also, with no air molecules to transmit sound then the noise reduction figures are equally impressive and better than even the best standard double glazing.

A further benefit with Vacuum Glazing not being reliant on dessicant technology to control moisture within the unit is increased service life. You generally get a 10 year guarantee with a 25 year life expectancy.

By extracting the air from the space between the panes they become subject to very high atmospheric pressure trying to push the panes together, so to avoid them touching there are tiny micro-spacers to hold the panes apart. These are barely noticeable when installed, certainly less noticeable than todays’ wide edge seals and rubber gaskets!

Development of this type of double glazed unit construction began 20 or more years ago and has been commercially available now for over 10 years.