Window blind

A window blind is a type of window covering. There are many different kinds of window blinds which use a variety of control systems. A typical window blind is made up of several long horizontal or vertical slats of various types of hard material, including wood, plastic or metal which are held together by cords that run through the blind slats. Vertical blinds run along a track system which can tilt open and closed and move side-to-side. Window blinds can be manoeuvred with either a manual or remote control by rotating them from an open position, with slats spaced out, to a closed position where slats overlap and block out most of the light. There are also several types of window coverings, called shades, that use a single piece of soft material instead of slats.

The term window blinds can also be used to describe window coverings more broadly. In this context window blinds include almost every type of window covering, whether it is a hard or soft material; i.e. shutters, roller shades, cellular shades (also called honeycomb shades), wood blinds, Roman shades, standard vertical, and horizontal blinds (also called Venetians). In the United Kingdom, awnings are sometimes called blinds or shades.

Window blinds are generally sold as either ready-made or made to measure. As the names suggest, blinds that are ready-made are manufactured to set sizes based on typical window dimensions, whereas blinds that are made to a measurement are cut to a specific width and drop to match the window. The advantage of ready-made blinds is their availability and cost, whereas blinds that are made to measure will be more expensive but better fit the dimensions of a window.

Aside from coming in different dimensions, window blinds can also come in a variety of different styles, materials, colours and patterns. Below is a list of several popular styles of blinds:

Window blinds can be drawn manually using a cord, or automated through motorization. Controls for motorized blinds can be from a wall switch or keypad, remote control, or computer, eliminating the need for cords and allowing control of otherwise inaccessible windows. A number of modern homes are integrating blind control with central C-Bus solutions. This control provides ease of use and is effective for controlling blind operation to reduce heat loss during winter or minimize heat from the sun during summer.^{[citation needed]}

Panel blinds, sometimes referred to as Japanese blinds as they are based on Japanese shōji, are thin blinds in a panel shape that run along a track. Almost any fabric or paper can be employed, although 90% of all shoji blinds use white polyester to imitate 'washi' Japanese paper.^{[clarification needed]}

Cellular shades or cellular blinds, sometimes referred to as honeycomb shades, are a type of window blind made of a long and continuous fabric with a cellular structure when opened and fold onto themselves when closed. The honeycomb shades were introduced in 1985. The fabric is often made from soft paper or cloth-like material and is available in a variety of different structures including single cell, double cell or triple cell. Cellular blinds work by trapping air inside the cell structure once opened and create a barrier between the window surface and the room. Due to the unavailability of standardized tests, no ranking system currently exists to compare the efficacy of these blinds.

Windows and doors make up for almost one-third of a home's total thermal loss, according to the Department of Energy (United Kingdom). This applies to heat loss in winter as well as entry of undesired heat in summer. When air inside the room comes in contact with windows, it is cooled or warmed. By convection, this air then circulates around the room. Cell shapes in the blinds hold trapped air and create a barrier between the window surface and the room, thus lessening the transfer of heat. Shades, however, provide only slight control of air infiltration.