Tankless Hot Water Heaters

A tankless hot water heater is a compact, wall-mounted appliance that heats water as it is required. For this reason, it is also called a continuous or on-demand heater. It is more efficient and cheaper to run that a conventional heater which heats the water in its storage tank every day, whether it is used or not. They are powered by either gas or electricity and only use enough power to heat the water required. While they have a high cost, they pay for themselves within a few years by saving power.

The main benefits of using a tankless hot water heater are saving money and never running out of hot water. Storage tanks that have a large capacity also have a large standby loss. This is the wasted energy from having unused hot water sitting in the tank all day. This standby loss is the reason that storage tanks have a much lower energy efficiency compared to tankless heaters. Tankless heaters also do not run out of hot water unless they suffer a malfunction or a loss of their power supply.

The tankless hot water heater start operating when a tap is turned on. A flow sensor detects when water is flowing through the pipe and it signals the computer to start the heater. When the flow stops, the flow sensor signals the computer again to turn the heater off. The flow has to be substantial to trigger the sensor and there is a minimum flow rate below which the heater will not turn on. Heat from the gas burners or electric element is transferred to the water through a solid copper heat exchanger. It takes several seconds for the heat exchanger to warm up so there is a slight delay before the water flowing out of it becomes hot.

The computer in a gas heater automatically opens the gas valve, starts the exhaust fan, and ignites the gas using piezoelectric sparkers. Large gas heaters have a vent that takes the fumes out of the room, while small heaters usually release the fumes into the room. When the water flow stops, the computer turns off the gas valve and the burners go out. The electric models use a heating element that is wrapped around the heat exchanger, similar to the element used in a radiator or electric oven.

Before buying a tankless hot water heater, an appropriate size should first be worked out. The size of the unit will depend on the required flow rate and hot water temperature, as well as the inlet cold water temperature. The flow rate is important because a slower rate produces a higher temperature rise, while a higher rate produces a lower temperature. Multiple heaters can be connected together to provide a greater flow rate if required. However, this also increases the running cost, and there may be a point where it is more economical to use a storage tank than several tankless heaters.

Installing a tankless hot water heater requires several plumbing connections, and possibly a gas connection or electrical circuit. Most units will need to be installed by a professional, but some of the smaller units that are plugged into a powerpoint can be installed by anyone. Small heaters are mounted on the wall above a sink, while large heaters are usually installed under the sink. If a vent for a gas heater also needs to be installed, first determine where a hole in the roof or wall can be made so that the vent can pass through it. It may be necessary to by an electric heater instead if a vent cannot be installed.

This Tankless Hot Water Heaters Review is Written/Updated on Dec 4th, 2009 and filed under Home Appliances. Both comments and pings are currently closed.

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