Single Element Vs. Dual Element Electric Water Heater

Single and dual element water heaters offer several benefits for the homeowner. Often, the new homebuyer doesn't pay attention to which heating elements are present in the home, a mistake that can cost money in heating water and eventual repair bills. The careful consumer can work the technology to his advantage by choosing a water heating system that best suits usage needs, thereby trimming the expenses and, more importantly, keeping the water warm.

Water heating systems have benefits and weaknesses.

What is a Single Element Water Heater?

A single element or single thermostat water heater is one with a single means of temperature control for the entirety of the water tank. Its single thermostat is responsible for heating the water throughout the system to a factory preset temperature (usually 120 degrees Fahrenheit) and usually incorporates a degree dial where that temperature may be modified. These single element units are not as common as they once were, the market having given way to the more efficient and cost-effective dual element models.

What is a Dual Element Water Heater?

A dual element water heater is a two thermostat system, an upper and lower, that heats water in its tank one element at a time. The upper thermostat takes first priority, heating the water to a preset temperature before powering up the lower thermostat to heat the water to its final temperature. Only one heating element will be active at any one time. Water is more evenly heated in this system, which is now the most common in homes built today.


The dual element is the more efficient of the two water heating systems. It heats water quicker than a single element unit, as water is moved from one end of the tank to the other, whereas a single element system heats from the bottom up only. That being said, a single element heater is also easier to maintain with only one thermostat to replace if it malfunctions, and is generally cheaper to maintain. Single element thermostats generally retail for less than twenty dollars.


Dual element thermostats are not interchangeable. "Each must be replaced with a thermostat with the same function: upper for upper, lower for lower," says a servicer and manufacturer of water heaters. "They cannot be interchanged, as they perform specific functions." This lack of ubiquity translates to a tougher time finding replacement parts on short notice. Imagine a week of cold showers while the shop finds the specific lower thermostat.

They also point out that thermostats from dual systems may not be used in single element water heaters either. The two systems as a whole are not compatible. The single element is also easier to replace as a DIY job without the assistance of a trained professional. The cost of maintaining a dual system is also higher than that of the single element as it has more parts to replace: two thermostats versus the one.

The Winner

For ease in maintenance the single element water heater is the recommended choice. For those seeking a hot shower with minimal chance of a cold initial burst, a dual element would be the better selection. The full maintenance cost of the dual element does not eclipse its efficiency however. Dual thermostats are no more expensive ($14 to $25) than single elements, there's just one more to replace. Remember that in newer homes a dual system will most likely already be in place and can't be changed unless the entire tank is replaced, which can be more expensive than just enjoying what's already in place and working properly.