Comparing Thermopiles Versus Thermocouples

Thermopiles and thermocouples are both utilized to yield electricity by measuring and sensing temperature. Both the appliances are similar and are used in a wide array of industrial and everyday applications. Some amateur individuals get confused between a thermopile and a thermocouple. The article highlights a brief comparison between the two.

What is a thermopile?

It is a device that consists of thermocouples organized in a series or parallel combinations. Unlike thermocouples, thermopile yields more voltage output to identify the temperature of equipment. The high voltage output production is because of the connections of multiple interlinked thermocouples. To result in more output, it is vital to ensure that the thermocouple connections are not weak.

What is a thermocouple?

In a thermocouple, the voltage output is the result of the connection of two wires from different materials. Appliances that make use of a gas flame, the thermocouple is responsible for yielding voltages, which also help in detecting the temperature. The voltage output and the temperature variation at both ends of the wires are proportional to each other. The working mechanism is similar to that of electric conductors, where the heat rests at the first end and then transfers to the second end. This is how voltage in thermocouples is generated, resulting in electricity.

Fundamental differences

There are some fundamental differences between a thermopile and a thermocouple. They are mentioned below:

●      Voltage output

Both thermopiles and thermocouples can detect or sense temperature. A thermopile has a higher temperature range than a thermocouple.

●      Size

Thermopiles have a thick size, while thermocouples have thinner construction.

●      Design

A thermopile is designed in a way that consists of connected thermocouples either arranged in a series, or parallel combinations. On the other hand, a thermocouple consists of two types of wires from different materials. The heat is on the first wire end, which travels to the second wire and thereby yields electricity.

●      Temperature

Thermopiles are ideal for sensing and measuring non-contact temperature, while thermocouples measure contact-based temperature.

Can thermocouples replace thermopiles?

Since a thermopile consists of multiple connected thermocouples arranged in a series or parallel format, often people question whether the former can be replaced by the latter. The answer is no. A single thermocouple cannot be used to replace a thermopile. The simple reason is that a single thermocouple fails to perform the same level of function that a thermopile does.  Several gas appliances utilize a thermocouple to sense temperature and control the gas flow. On the other hand, a thermopile is responsible for navigating the light and helps to turn on the fire.

Since a thermopile has multiple interconnected thermocouples, the electricity generation potential is high. When one compares a thermopile and a thermocouple, it is evident that thermopiles are more effective and accurate in sensing radiation than thermocouples.

Thermopile versus thermocouple in fireplaces

Gas fireplaces and fireplace inserts make use of thermopiles and thermocouples to yield electricity. When the fireplace system is turned on, the gas source pilot generates heat, which transfers inside the thermocouple. When the heat is received in the next thermocouple signal end, there is electricity output. The fireplace makes use of the produced voltage output to operate the gas valve section. This allows the gas to disperse and the fire turns on.

Fireplaces that come with thermopiles can be connected to the thermostats for monitoring temperature. This is because thermopiles yield more electricity than thermocouples. Whereas, the fireplaces that are equipped with thermocouples miss out on apt electrical output in the process. Therefore, thermocouples are used mainly to sense and detect the temperature in fireplaces. On the other hand, thermopiles are used to generate electricity to operate the fireplace valve and also regulate temperature when there is a thermostat involved in the fireplace system. Such accurate detection of electricity voltage between every section of thermocouple pairs is possible in a thermopile device.


There is a lot of confusion among several people while discussing thermopile versus thermocouple. Both the devices are based on the thermoelectricity principle to yield electricity by measuring the temperature. The devices are used widely in several applications, commonly in gas fireplaces, and fireplace inserts. To understand the differences between a thermopile and a thermocouple, one must understand their distinct working mechanism.

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