Although single panes of glass are perfectly practical in many situations, they don't tend to be used by window manufacturers any longer other than for specific applications. This is because lone sheets of glazing in a fenestration unit are not as effective as two or three in many respects. Although a single glazed window is perfectly good for seeing in and out of, it is not considered to be particularly secure or able to provide adequate insulation. Nor are single glazed windows as good at preventing noise ingress or from reflecting away the sun's heat than double glazed ones. Why should you consider double glazing for your home, shopfront or office?
As mentioned, security is a big part of what makes single glazed windows inferior to double glazed ones. If an intruder is working out a way of getting into your property, then the likelihood is that he or she will choose the most vulnerable point of access. If you have a single glazed window in your home, then this will be the preferred area. Single glazed windows can be broken with a surprising amount of ease. By contrast, quality double glazed windows are harder to break apart. If a double glazing unit is made with a robust frame, such as uPVC or aluminium, then it becomes even harder to get past.
Losing heat from inside your home may be beneficial during summer but all you need to do is to open the window to achieve that. During winter, on the other hand, windows should trap heat inside to prevent losses and to keep your energy bills as low as possible. Double glazing is over twice as good at trapping heat within a building not because of the additional thickness of the glass — although this helps — but because an air cavity is created between the panes which generates an invisible insulating layer. The same can be said when your windows ought to protect you from the sun's rays in summer. Double glazed windows are better at keeping your home cool than single glazing because of this insulating effect.
All structures suffer from a certain amount of noise that comes in from outside. If you live by a busy road, a factory or an airport, then double glazing can be invaluable. When the windows are shut, double and treble glazed panes can almost eliminate the noise from outside, especially low frequencies from things like passing motor vehicles. Even if you live in a sleepy town rather than a sprawling metropolis, double glazing can help to lessen the effect of noisy neighbours!