Windows are among the most notable features of a house. They have a big influence on the overall look of the structure. They also serve several vital functions such as daylight control, natural ventilation and outside monitoring. Windows need careful consideration whether building a new house or planning a replacement. Their positioning, number, size and materials will all affect their performance. The material used is particularly important because it will determine the aesthetics of the windows, their ability to endure harsh weather, the thermal efficiency and the price of the units. Popular types include PVC, wood and aluminium windows.