An attic (sometimes referred to as a loft) is a space found directly below the pitched roof of a house or other building; an attic may also be called a sky parlor or a garret. Because attics fill the space between the ceiling of the top floor of a building and the slanted roof, they are known for being awkwardly shaped spaces with exposed rafters and difficult-to-reach corners. While some attics are converted into bedrooms, home offices, or attic apartments complete with windows and staircases, most remain difficult to access (and are usually entered using a loft hatch and ladder). Attics help control temperatures in a house by providing a large mass of slowly moving air, and are often used for storage. The hot air rising from the lower floors of a building is often retained in attics, further compounding their reputation as inhospitable environments. However, in recent years attics have been insulated to help decrease heating costs, since, on average, uninsulated attics account for 15 percent of the total energy loss in average houses. A loft or mezzanine is also the uppermost space in a building but is distinguished from an attic in that an attic typically constitutes an entire floor of the building, while a loft or mezzanine covers only a few rooms, leaving one or more sides open to the lower floor. Attics are found in many different shapes and sizes. They also have many uses: in residential buildings, attics are either small unusable spaces filled with insulation, either spaces with storage/HVAC equipment. Some commercial buildings also have attics under their pitched roof- these ones are usually used for storage, as a mechanical floor, or as a roof access space. Some attics in commercial buildings contain electric circuits and wires for lighted signs on the building’s walls. Etymology The word "attic" is derived from the Attica region of Greece and comes from Attic style architecture. The term referred to "a low decorative façade above the main story of a building" and, as used in the phrase "attic order", had originally indicated a small decorative column above a building's main façade. Ventilation Modern building codes permit both vented and unvented attics in all climates, if a building is otherwise correctly constructed. However, unoccupied attics should usually be ventilated to reduce the accumulation of heat and moisture that contribute to mold growth and decay of wood rafters and ceiling