Selecting a Water Heater for Your Remodeled Home

A home hot-water system consists of a heater and a piping system that parallels the cold-water pipes to the faucets where hot water is desired. The heater is fueled by gas, oil, electricity, or the sun, depending on the fuel that is available in the area and the preference of the homeowner. Most heaters cannot heat water as fast as it can flow from a shower head or faucet, so they have a tank in which to store a quantity of hot water.

Home water heaters are generally available with tanks of 30 to 82 gallon capacity. The once common 20 gallon tanks have become so unpopular that most manufacturers don't make them any more. Gas and oil-fired heaters are usually 30 to 60 gallons. Electric heaters, because they heat water more slowly and have a longer recovery time, have tanks that can hold up to 82 gallons. Some manufacturers make a rapid-recovery electric water heater in which the upper heating element operates independently to heat the top quarter of the tank quickly. When the top quarter is hot enough, the upper element goes off, and the lower one comes on to heat the rest of the water slowly.

The size of your water heater tank depends on how much hot water your family needs at the time of peak usage- for example, in the morning or evening when everyone takes a bath or shower. Usually the number of bedrooms in a house is used to determine the size of the water heater. For a one or two bedroom house, a 30 gallon tank is recommended; for three bedrooms, a 40 gallon tank, and so on. If you have several children, you may want to have a larger tank than recommended.

In some areas of the United States demand water heaters are available. Also called tankless or instantaneous water heaters, they are common in Japan and Europe but haven't been used in this country to any great extent since the copper shortage during World War II. These heaters have an intricate grid of copper ducts very much like an automobile radiator. When the hot water is turned on and flows through the heater, a large gas flame envelops the grid and heats the water to the desired temperature as you use it. Because this kind of heater heats water only as you use it and does not have to go on periodically to keep a whole tank of water hot, it uses up to 20 percent less fuel than a conventional tank heater. You can find out about availability in your area through a wholesale plumbing supply or solar equipment dealer.

Tank-type water heaters are basically simple devices. The consist of a thermostatically controlled burner or heating element that heats the water and can insulated tank to hold it until someone wants to use it. Because hot water is corrosive to metals, most quality heater tanks are glass-lined to help prevent them from rusting through.

Gas-fueled heaters have a burner very similar to the one on a gas kitchen range. A pilot light lights the burner when the thermostat indicates the tank water is cooler than desired. Hot exhaust gases from the burner go through the flue in the center of the tank, where they continue to heat the water as they pass by.

Oil-fueled heaters are less common but still in use where oil-fired furnaces are used. The water tank is suspended in the middle of the heater, and a small version of an oil-furnace blower heats the bottom and sides with hot gases before they are vented out of the flue.

Electric water heaters have one or two heating elements that project through the wall of the tank into the water. Because there is no combustion, no flue is needed and no toxic gases or hot gases are emitted. An electric heater, therefore, can be placed in a closet or bathroom, where the building code would not allow a gas or oil-fueled heater. All water heaters do need a drain in case of overflow and for regular maintenance draining.