Water heaters for hot drinks operate at or close to boiling point (100oC) and special products are designed for this purpose. The choice essentially comes down to traditional manual catering urns or automatic units. Automatic boiling water heaters are connectly directly to the water supply and perform very well but are significantly more expensive. These may be either wall mounted above a sink or mounted on a counter top and are plumbed in to the cold water mains supply. In 'boiling tap' models a dispensing tap is mounted on the work surface with the storage unit being located out of sight beneath the work surface. Most units are 3kW or less which enables simple electrical installation.