A mains electricity (AC-powered) device designed to be used together with a laparoscopic gas distention system or other gas source to condition the insufflation gas stream [typically carbon dioxide (CO2)] by automatically heating and humidifying the gas before introduction into the peritoneal cavity or a wound during laparoscopic or open surgery. It is electronically controlled and has controls and displays for the user to operate and monitor the gas conditioning process which happens within an interchangeable humidification chamber that is fitted to this device. The gas is delivered to the operative site via a dedicated heated tubing set.