Are you considering replacing the water heater in your home? If so, you should give some serious thought about what type of unit you want to install. All water heaters have their pros and cons, and the type you choose can affect how much hot water you can use and also how much you pay for hot water. To help you determine which option is best, this article will explain how all of the different types of water heaters work.
How Traditional Gas and Electric Tank Water Heaters Work
The majority of homes in the US have either a traditional gas or electric tank water heater. This type of unit typically stores anywhere from 40 to 80 gallons of hot water and always keeps the water at the desired temperature.
Gas units have a large gas burner underneath the tank and a vent pipe that runs up through the middle of the tank and connects to the exhaust flue. The majority of the heat flows from the burner, through the bottom of the steel tank and out into the water. As the hot fumes produced by the burner flow up through the vent pipe, the pipe also becomes quite hot. This means that some heat also flows out of the vent pipe into the water.
Most electric units have two electric resistance heating elements. The lower heating element is near the bottom of the tank and the upper element is near the middle. These elements are similar to those in an electric baseboard heater or a toaster. As electricity flows through the wires in the element, they become extremely hot. The heat then flows out of the elements into the water.
All traditional water heaters have something known as a dip tube that extends from the cold water inlet down to near the bottom of the tank. Whenever you draw hot water out of the tank, cold water flows in through the dip tube and empties into the bottom of the tank. This is important because the hot water flows out of the top of the tank. The dib tube prevents the cold water from mixing with the hot water as much. This keeps the temperature from dropping as much so that the water heater doesn’t have to run that long to bring the temperature back up.
How Gas and Electric Tankless Water Heaters Work
Gas and electric tankless water heaters are more efficient than traditional units since they work on demand instead of having to keep the water constantly hot. As soon as you open a faucet or turn on your shower, water begins flowing into the unit. The water triggers the flow sensor, which then signals the gas burner to light or the electric heating elements to turn on.
All tankless water heaters have a heat exchanger that transfers the heat from the burner or electric heating element to the water. In a gas unit, the heat exchanger is essentially a large vent pipe that absorbs lots of heat from the fumes produced by the burner. The water coming into the unit flows through a pipe that is coiled or wrapped around the outside of the heat exchanger. As the water moves around the heat exchanger, it absorbs enough heat that it reaches the desired temperature before flowing out of the water heater and into your hot water lines. A sensor inside the unit constantly measures the water temperature and adjusts how much heat the burner produces as needed to ensure the water is at the correct temperature. This process works the same way in an electric unit except that the water flows through a series of pipes located inside the electric heating element.
How Indirect Water Heaters Work
Indirect water heaters are somewhat common in homes that have a boiler and radiant heating. This type of water heater is unique as it works passively and doesn’t use any energy on its own. Instead, it relies on the boiler to heat the water inside of its storage tank.
Inside the tank is a coiled pipe that runs all the way up through the middle of it. This pipe extends from the boiler to the water heater and then back out of the water heater to the boiler. When hot water is used or the water starts getting colder than the desired temperature, the boiler will start pumping extremely hot water through the pipe. As the water flows through the pipe in the tank, it releases lots of heat so that the water in the tank starts to become hotter. All of the water in the pipe eventually flows back to the boiler to be reheated.
The main issue with indirect water heaters is that they heat quite slowly. This normally isn’t much of a problem when you’re not using much hot water. However, if you use up most of your hot water, it can sometimes take a couple of hours before the water is again as hot as you want it to be. The reason is that the water from your boiler is usually only 40-60 degrees hotter than what you have your water heater set to. This means much less heat flows out into the water at a time compared to other types of water heaters.
How Electric Heat Pump Water Heaters Work
Electric heat pump water heaters are quite similar to indirect water heaters, as they have the same type of coiled pipe inside the tank. The difference is that these units use a heat pump and refrigerant instead of a boiler and hot water.
The heat pump first circulates the refrigerant through an evaporator coil similar to the one your AC system has. At the same time, the fan pulls warm air in from the surrounding area and blows it over the evaporator coil. As refrigerant moves through the coil, it absorbs heat and starts to become warmer. Before flowing through the pipe in the water heater tank, the refrigerant first goes through an expansion valve. This causes the refrigerant pressure to decrease, which leads to the refrigerant boiling and turning into an extremely hot gas. The hot gas is then pumped through the coiled pipe in the tank, and the refrigerant releases most of its stored heat into the water.
Heat pump water heaters are generally the most energy-efficient option, but they also heat more slowly just like indirect water heaters. However, the majority of heat pump water heaters are hybrid units that also have the same type of electric heating elements found in a traditional electric water heater. Whenever you use lots of hot water and the water in the tank gets much colder, the heating elements will turn on to help bring the water up to temperature more quickly.
The one issue with this is that the electric heating elements use much more energy than the heat pump. This is why heat pump water heaters need to be installed in a warm location so that the heat pump works effectively and the electric elements don’t have to run as often.
If you need to install a new water heater in your home, Childers Air Plumbing & Electric is ready to help. We also offer professional water heater repairs and maintenance, and our team can handle all of your other plumbing, HVAC and electrical needs as well. Give us a call to schedule a service appointment in the Beckley area or if you have any questions.
