All About Water Heaters

The first water heater was invented in 1868, and since then, the systems have undergone various changes and improvements

Before the invention of the water heater as we understand it today, water was often heated over a stove or fire, then dumped into a tub for bathing, for example. In the mid-1860s, an English painter patented the first residential water heater, but it was not until 1889 that the design of the system was developed and acted as the initial step toward the modern water heater. Nowadays, all it takes is a simple switch, and you have access to hot water for a shower, dishes, laundry, and more. But, how do these systems work, and what are the differences between the different types of water heaters?

Types of water heaters

There are various types of water heaters, and they all work similarly. By far, the most popular type is the traditional tank water heater, and a tank water heater is either powered by gas or electricity. There are also new, more efficient and cost-effective water heaters emerging.

Tankless water heaters do not rely on water stored in a tank in order to provide hot water. Instead, a small amount of water flows through the pipes at all times, so when a hot water faucet is turned on, energy is saved by not having to wait until an entire storage tank of water is heated. While a tankless water heater does, generally, also provide a home with hot water faster than a tank water heater because of how it operates, it is not necessarily immediate. 

Solar water heaters are now another option for sustainable living, and they work by installing a piping system that uses the heat of the sun. Even though the upfront cost of purchasing and installing one can be expensive, if you live in a climate that sees a lot of sun or you do not mind having a secondary heat source, the ongoing costs are practically non-existent.

How water heaters work

Electric Water Heaters
In electric models, the thermostat is mounted against the side of the internal tank. When the thermostat senses that the internal temperature has fallen below the programmed temperature, it triggers a switch (or two, in the event of a dual element system) that allows electricity to flow to the heating element. The heating element is submerged in the water of the tank and heats up in the same way that an electric stove burner works, by passing electricity through a resistant material and converting energy into heat. When the thermostat senses that the water has reached the correct temperature, it shuts off the power.

Gas Water Heaters
Gas models also have a thermostat. They have a special sensor called a thermocouple that senses whether the pilot light is currently burning. If the pilot is out, the thermocouple will not allow gas to flow to the burner. When the water temperature in the tank falls, the thermostat sends a signal to the gas control valve, which checks the signal from the thermocouple to ascertain that there is a pilot light. If so, a valve opens, allowing gas to flow to the burner, igniting a flame. The flame heats the bottom of the tank, causing warmer water to rise while cool water sinks, creating a natural circulation cycle. When the water temperature reaches the desired setting, the thermostat sends a signal to the gas control valve, instructing it to turn the gas flow off again.

Variations on Water Heaters
Some water heaters and most tankless systems use a hot water recirculating system which keeps hot water moving through the heating system and prevents hot water flow from being interrupted with “cold” spurts of unheated water. Solar water heaters use a similar system as the primary method of heating water. As hot water rises, it expands, pushing cooler water ahead of the hot water and circulating water through the internal pipes of the solar heater. In principle, a solar water heater is really just a circulation system that passes the water continuously through a concentrating device that is exposed to direct sunlight and channels heat into the core of the solar heater.

Choosing the right water heater for your home

There are many factors to consider when you decide to purchase a new water heater. The major factors in narrowing your decision of which water heater is right for your home include:

Water storage capacity
Generally, people are drawn to whole house systems like tank water heaters and many tankless water heaters because they can provide hot water to more than one fixture at a time. If, however, you have a smaller home or you’re ok with only a few fixtures receiving hot water at one time, you may not need as much water storage capacity. 

Point-of-use systems are individual units that install directly under the sink or in a closet. These systems deliver instant hot water to a specific location and typically augment a whole house system when instant or additional hot water is needed.

If your space will not accommodate a standard-size water heater, there are:

  • Lowboys or Short: shorter and wider than a normal water heater, allowing them to hold the same amount of water while still fitting in areas with limited headroom
  • Tall: ranging from 50 to 76 inches and can hold up to 100 gallons of water

Energy Star, the government-backed symbol for energy efficiency, helps consumers save money and protect the environment through energy-efficient practices. Check to make sure your system has the blue Energy Star label.

A WiFi module is now available with some electric water heaters that will control your water temperature remotely. This allows you to customize your schedule so that hot water is available only when needed.


To have your water heater assessed, repaired, replaced, or to get additional information, schedule an appointment with our easy Online Scheduling or by calling 812-339-9114.




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