How Does Double Glazing Work?

If you live in an area where winters are particularly long, you will find it advantageous to switch from traditional windows to double glazed units. There are many benefits associated with the latter: Double glazed windows are more energy-efficient and harder to break. They also do a better job of reducing noise.

So, how exactly does double glazing work? Contrary to what many people think, the principle behind the technology is fairly simple – but it’s worth understanding the science to help you to make better decisions about which features are worthwhile, and which are simply marketing gimmicks.

First, two glass panes are held together in a frame. Glass panes used in double glazing are usually tinted although clear varieties are available. The tint helps to absorb solar radiation so that during the warm summer months, your house will not feel like an oven.

The most common tints are bronze, grey, blue and green. Higher-end glass panes may employ a combination of reflective, anti-glare and heat-absorbing technologies.

Second, a barrier of air or gas is maintained between the two window panes. Called a spacer, this gap is key to reducing heat loss and noise. Heat will always move from higher to lower temperature. In solids (like glass), this happens very quickly because the particles are tightly packed.

Heat transfer is much slower in gases (like the air or argon trapped in the spacer) because the particles not only move freely but are also located far apart from each other. The effect is improved insulation. Heat does not escape easily from the window. Your home stays warmer longer.

Sound travels slowest through air and accounts for how double glazing can keep noise levels down. Additionally, some spacers come with foam padding designed to absorb echo and muffle sound. This is a great way to host late-night parties without disturbing the neighbours.

Finally, the barrier is sealed to prevent the entry of outside air and to avert moisture build-up in the inner glass panes. Conventional spacers contain dessicant as an added precaution against condensation.

There are several factors that can affect the overall efficiency of double glazed windows. These include the kind of window frame used, the thickness of the glass and the space between them.

Regardless of the variables, all double glazed windows operate under the same basic principle. Traditional windows utilize only one pane of glass, whereas double glazing uses two. Between the two panes of glass is an air or gas-filled barrier that works to reduce heat loss and regulate heat gain.