- Standard water coolers consist of a unit that holds a bottle of water with a valve that allows the water to flow when opened. The pipe that the water flows through has a cooling unit attached, which quickly reduces the water's temperature as it flows. Some more advanced water coolers feature an adjustable thermostat on the cold water line so that you can change the water's temperature (should you find it too warm or too cold), while more basic water coolers don't control the temperature as precisely. The water bottles are easily removed once empty by lifting them out of the unit. The new bottle that will replace it will have a rubber seal holding the water in that will be shifted to allow for water flow once it's inserted into the water cooler unit.
- Some water coolers feature a second water valve that allows hot water to be dispensed in addition to cold water. This second valve operates much the same as the cold water valve on a standard water cooler, but instead of having a cooling unit attached to it the pipe is connected to a heating unit. Water cooler units with a thermostat generally have a second thermostat to control the heating unit on models that produce both hot and cold water. Although most water coolers that have a heated water option allow water to flow through both valves at the same time, having both valves open at once can reduce the water pressure of both and may result in water temperatures varying slightly from the norm.
- A more advanced version of the water cooler is the bottleless water cooler. These units hook into your home or business water line, eliminating the need for bottles of water to be changed out (while also securing the water cooler in one location). Other than the source of water, these coolers are very similar in their function to bottled water coolers. The water pipe passes through a cooling unit, dropping the temperature of the water before it reaches the open valve. Units with a heating unit also exist as well, allowing you to have both hot and cold water on demand without the need for water bottles.
