• Gas Vs. Electric Storage Tank Water Heaters – Both gas and electric water heaters are nearly the same with the exception of the heating element. The gas unit has the burner underneath the storage tank where the electric unit has the heating element inside the storage tank. The gas unit has a chimney that runs up the middle of the storage tank. This chimney allows the used gases and heat to escape.
• The Storage Tank – Both electric and gas storage tank water heaters have a tank that holds the heated water until it is ready to use. The tanks are generally tested to hold at least 300psi. Most tanks have a glass liner to prevent the storage area from rusting.
• Keeping the Water Hot – Both storage tanks have insulation to help the hot water stay hot. In most cases the insulation thickness will increase as the cost of the tank increases. The newer codes for water heaters started April 16, 2015 and the insulation is much thicker all away around the tank by a substantial amount increasing the energy efficiency.
• Preventing Disaster – Both tanks have a drain valve that lets a user drain the water from a tank. They also have a pressure release valve to prevent the tank from exploding. Electric water heaters also have a high limit control is a safety device along with a pressure relief valve.
Gas water heaters have a control valve along with a thermal coupling that is also a safety device along with a pressure relief valve also.
• Corrosion Prevention – Water heaters will naturally rust and decay from the inside out. To prevent the decay, a sacrificial rod (anadode) is placed in the tank. This rod decays first and therefore prevents critical internal parts from corroding.
• Heating the Water – The Controller or thermostat maintains the water temperature inside the storage tank. Although water heaters can maintain a temperature of up to 180 degrees Fahrenheit the normal operating temperatures are between 120 – 140 degrees Fahrenheit.
• The Flow of Hot and Cold Water – Water heaters do not have a pump to move water in and out of the tank. They rely on the water pressure present in the house to allow the cold water to flow in and hot water to flow out. City water pressure is generally between 50 and 85 psi. As a plumbing fixture is opened on the hot side or mixed allows the water to flow from the main cold water line through your house and out of the faucet. As you create a demand for hot water, cold water flows into the tank. A dip tube that is installed on the cold side inlet diverts water down to the bottom of the water heater pushing hot water up to the hot water outlet of the water heater. As the temperature in the tank falls due to the cold water entering, the thermostat turns the heating elements or the burner on a gas water heater.