Since water heating is a thermodynamic process using an energy source to heat water above its initial temperature and comprised of parts that can fail, maintaining its hot water production is crucial to your home needs. Typical domestic uses of hot water are for cooking, cleaning, bathing, and space heating. Commercial applications include both hot water and heated water to generate steam. Water heaters, boilers and heat exchangers are the mechanical processes used to heat water for a variety of domestic and commercial uses. Water heaters come in two basic forms: tanks and tankless.

Some of the more popular domestic water heaters are:

• Conventional Tank Water Heaters

  Most water heaters are tank water heaters which keep a cylindrical tank full of hot water in your home at all times. The typical sizes available for household water heaters that utilize a tank are between 20 and 100 gallons. When hot water is required the water is circulated to the open faucet. Conventional tanks utilize electric, natural gas, propane, oil, solar or geothermal power as an energy source to heat the water.

• Electric Water Heaters

  The typical electric water heater is wired to a 220-volt circuit. To heat the water, the current passes through electrical-resistance heating elements—usually two, one at the middle of the tank and one at the bottom.

  Power is delivered to each element through a thermostat—a switch that senses the water temperature. When the temperature drops, the switch closes to allow current flow, and it opens when the temperature reaches its preset limit. Thermostats have a dial for setting the maximum water temperature–generally between 130 degrees and 140 degrees F, or as low as about 120 degrees F for increased energy savings and scald protection.

  When a hot water tap is opened, cold water enters the tank through the dip tube and the drop in temperature triggers the thermostat and element at the bottom. As the water at the top of the tank is replaced by cool water, the temperature at the top thermostat drops, and its element kicks in. When the tap is turned off, the heating elements continue to carry current until the thermostats are satisfied.

• Gas-Fired Water Heaters

  An alternative to electric water heaters is gas-fired, usually utilizing natural gas or propane. Instead of electrical-resistance elements, gas-fired heaters have a burner that’s fed gas through a control valve and a thermostat switch. The burner is usually situated to throw a flame under the tank. The exhaust gases are vented either through a hollow core at the center of the tank or around the tank sides. Because gas-fired heaters heat the tank, which in turn heats the water, there will be more wear and tear on the tank than with electric heat. A gas-fired heater, therefore, may have a shorter life expectancy than an electric heater.

• AirTap – use your existing water heater!
  (BRAND NEW TECHNOLOGY)

  Imagine a water heater that heats its water–not by gas, nor by electricity–but simply by the air surrounding it. Your power or gas bills would be significantly lower, and you would be doing the environment a service by conserving a considerable amount of energy.

  The AirTap™ does just this. Once connected to your existing water heater, the AirTap™ unit acts as a conventional heat pump, using a compressor (powered by a low-wattage electric current) to extract heat from the surrounding air, and then sending this heat through long copper tubes into an adaptor where it is dispersed in your water tank. This, in turn, heats the water to the same degree as would a gas burner or electric heating component, distributing the hot water throughout your home safely and efficiently.

  To put into perspective, AirTap™ uses less power than an 8-cup coffee machine to run the compressor, and its energy consumption level is equivalent to keeping two coffee machines on for a day.

  According to the US Department of Energy, the average American household with a typical water heater (gas or electric) spends about 14-25% of its energy costs on heating water alone. (US Department of Energy, Energy Efficiency and Renewable Energy.) With the AirTap™ installed onto your existing water heater, you will reduce this percentage by about half.

  Even the current “alternative” water heaters are highly inefficient: tankless water heaters have an initial and operating cost 3 times that of the AirTap™. In addition to the high cost of the unit itself, the homeowner may be required to increase the electric service capacity of their home due to the massive electric load these tankless water heaters use.

  Solar paneled water heaters are also a pain on the pocketbook: the initial cost of a solar water heater system is 8 times as expensive as the AirTap™, while requiring the same amount of electricity to provide hot water on cloudy days. What’s more is that the environmental benefits of the AirTap™ are the same.

  After the first year, the AirTap™ will continue saving you $200 or $300 every year for gas or electric water heaters, respectively. Average savings are for a typical 4-person family. Depending on the cost of energy in your area and the amount of hot water you use, these savings can reach up to $500 or more every year.

• Tankless Water Heaters

  A tankless water heater, also called instantaneous, only provides hot water as needed, saving energy and, therefore, saving you money. They are designed to heat water directly without the use of a tank and are more efficient than conventional water heaters. The primary energy sources for tankless heaters are natural gas and propane. Tankless heaters are typically more efficient than storage water heaters. The absence of a tank saves energy as conventional water heaters have to reheat the water in the tank as it cools off, called standby loss. With a central water heater of any type, water is wasted waiting for water to heat up because of the cold water in the pipes between the faucet and the water heater. This water waste can be avoided if a re-circulating pump is installed, but at the cost of electricity to run the pump and wasted energy to heat the water circulation through the pipes