Double-glazed windows consist of two panes of glass separated by a space filled with air or gas, which acts as an insulator. This design helps to reduce heat loss in winter and keeps homes cooler in summer, making them energy-efficient. The gap between the panes also minimizes noise from outside, providing a quieter indoor environment. These windows are commonly used in residential and commercial buildings for their benefits in energy conservation and comfort. They can help lower heating and cooling costs, making them a popular choice for homeowners looking to improve their home's energy efficiency.