Double-glazing will filter out more external noise than single glazing. It will not eliminate sound completely.
If you think about how sound waves travel, they have a knock-on effect on the particles in which they come into contact.
Sound waves hitting a single pane of glass will cause vibrations which pass-through from the outside to the inside.
With double glazing and the added benefit of a layer of argon gas, the chance for sound waves to pass through are significantly reduced as the two panes of glass are not in contact with each other and Argon gas has different properties to air when it comes to how it behaves with sound waves.
Why not use triple-glazing?
The beneficial jump in energy efficiency from double-glazing to triple-glazing is not as effective as the jump from single to double and therefore the additional cost involved in manufacturing triple-glazing is not going to deliver a cost-benefit return for a domestic property.
It is more suited to specialist window needs, such as an airport departure lounge or other commercial and industrial uses.
When should I replace double-glazing units?
With regular upkeep and cleaning of uPVC or wooden-framed double-glazing units, you should expect to get decades of use and benefit from your double-glazing windows.
And don’t forget, your 2-year warranty covers windows and their locks.