All types of Water Heaters are available these days, Tankless Water Heaters, Standard Water Heaters, even Solar Water Heaters. Today’s technology and energy conservation requirements have forced manufacturer’s to upgrade the old systems to higher efficient units that no longer store various amounts of hot water. The conventional gas or electric water heaters are new and surely improved upon, lower resource usage with greener components. The tankless flash heaters give instant hot water only when asked for. And can be easily replaced in the same location without any major construction skills. With PEX and Sharkbite fittings the DIYer can avoid soldering and sweating joints. With slip and mechanical fittings its a whole new hot water game.

In household and commercial usage, most water heaters in North America are of the tank type. Also called storage water heaters, these consist of a cylindrical vessel/container in which water is kept continuously hot and ready for use. Typical sizes for household use range from 75 to 400 litres (20 to 100 U.S. gallons). These may use electricity, natural gas, propane, heating oil, solar, or other energy sources. Natural gas heaters are most popular in the United States and most European countries, since the gas is often conveniently piped throughout cities and towns and currently is the cheapest to use. Compared to tankless heaters, storage water heaters have the advantage of using energy (gas or electricity) at a relatively slow rate, storing the heat for later use. Larger vessel/containers tend to provide hot water with less temperature fluctuation at moderate flow rates.

Volume storage hot water heaters in the United States and New Zealand are typically vertical, cylindrical tanks, usually standing on the floor or on a platform raised a short distance above the floor. Volume storage hot water heaters in Spain are typically horizontal. In India, they are mainly vertical. In apartments they can be mounted in the ceiling space over laundry-utility rooms.

In western countries, where ambient temperature is colder, tiny point-of-use electric storage water heaters with capacities ranging from 8 to 32 litres (2 to 6 gallons) are made for installation in kitchen and bath cabinets or on the wall above a sink. They typically use low power heating elements, about 1 kW to 1.5 kW, and can provide hot water long enough for hand washing, or, if plumbed into an existing hot water line, until hot water arrives from a remote high capacity water heater. They are sometimes used when retrofitting a pump and recirculating plumbing in a building is too costly or impractical. Since they maintain water temperature thermostatically, they will supply hot water at extremely low flow rates, unlike tankless heaters.

In tropical countries, like Singapore, India: An ideal storage water heater may vary from 10 L to 35 L Usage of 6 Smaller hot water heaters are sufficient as ambient weather and water temperature are moderate.

The inner vessel of the Water heater is the single most important feature of a water heater. The best heaters have a copper inner vessel/container. The second most important feature may be the type of heating element. The cartridge elements score over tubular elements.