When storage needs outgrow reach-ins and chest freezers, a walk-in or cold room becomes the main store. It is built from insulated sandwich panels with a heavy-duty insulated door, then fitted with a refrigeration system, either a monoblock that mounts through the wall or a split system with an indoor evaporator and an outdoor condensing unit. Chiller rooms commonly run around 0 to +5 °C and freezer rooms around −18 to −25 °C.
A walk-in is a building project as much as an appliance. Floor insulation, door position, shelving layout, lighting, alarms, the inside door release and a strip curtain all need planning. Because so much stock is in one place, temperature monitoring and a response plan for breakdowns are essential.
A large hotel in Delhi might run one chiller room for dairy and vegetables, one for meat and seafood, and a freezer room for frozen stock, with daily receiving from suppliers going straight in. Many operators combine walk-ins with reach-ins at the cooking stations.