Double Glazing is a process that is used to produce insulated glass units (IGUs). In the process, two glass panes are fit into the same window frame. Insulated glass units are very beneficial for 'thermal resistance.' A standard single glazed window generates 21 - 31 percent of heat loss. https://stephens62.weebly.com/blog/steps-to-check-on-the-upvc-window-prices