An airing cupboard is a small room or closet which is designed to house the core elements of a heating system, such as a boiler or hot water heater. This term is more widely used in Britain; the phrase “hot press” is also used. The “airing” in this term comes from the common practice of hanging slightly damp clothing and linens inside this generally warm room, allowing them to thoroughly dry. These closets are also used for the storage of linens.
The size of an airing cupboard varies. It is typically located near a stairway landing or along a hall, and it is often close to a location where hot water is used, such a bathroom or kitchen. Depending on the heating and cooling system involved, the cupboard may hold a water heater, a boiler for hot water and steam heat, or some other form of heater. The space is designed to be large enough to allow relatively easy servicing of the devices it holds, and in some cases this area is deliberately built with room for storage.
As one might imagine, these closets are warm, thanks to the ambient heat generated by the heaters that they are built to store. This warmth has historically been utilized by housewives for things like drying delicate hand wash items, heating damp towels to get moisture out of them, and for drying wet coats, sweaters, and so forth. When an airing cupboard has shelves for storage, these can be used to store linens, ensuring that they stay dry even through long periods of storage.
The warm environment of the cupboard tends to make it a popular feature with house pets, especially cats, particularly when the area is used to store warm, fluffy towels. In households with pets, it is a good idea to check this area carefully before closing it to ensure that no animals are trapped inside; the alternative is to leave it open, although this tends to make the airing cupboard much cooler in temperature.
An important thing to remember when using an airing cupboard is that most heating systems require clearances. These clearances ensure that fires do not start, and they can help the heater run more accurately, as the thermostat gets a better reading when it is not heavily insulated with things like towels. When hanging or storing things in the closet, you may want to consider this; check the side of the heater or boiler for a label which indicates minimum safe clearances.