Double glazed windows use two sheets of glass with a gap in between them which creates an insulating barrier. Between the two panes of glass the space is filled with Argon gas, this creates an even more effective insulating barrier.
The reason behind replacing your existing windows for new Double Glazing is because all properties lose heat through their windows. Installing energy effiecient Double Glazing is an effective way of reducing your energy bills and keeping your home warmer and quieter.
There are different energy ratings related to Double Glazing ranging from an A (most effiecient) to a G (least efficient) Building regulations state that all new or replacement windows must be at least a C. There are now Triple Glazed windows that will achieve an A++ rating. Please see our Triple Glazing page for more information.