How to choose the correct thermal strip heaters?


Thermal strip heaters, also known as clamp-on or flat heaters, are a useful industrial heating solution. It is a flat strip with a rectangular cross section that is mounted on a surface and is used to heat the surface or air (gases). A bolt can be used for attaching the heater to the surface. Threaded terminals with nuts and bolts can also be provided for easy power supply connection. Strip heaters are available in a wide range of widths and lengths, utilizing the most proficient heating methods. There are numerous choices for mounting positions, terminations, as well as sheath material.

A thermal strip heater is made up of three components: a heating element, a protective sleeve or sheath, and a mounting mechanism. The heater’s physical strength is provided by the metal sheath. The heating element (NiCr) is located in the heater’s center and is then inserted in magnesium oxide (MgO). The MgO improves the thermal conductivity as well as dielectric strength of the element. The heater is then encased in the desired sheath material. This is an extremely rugged construction capable of high watt densities up to 35 W/in2. In addition, depending on the sheath materials used, the compacted strip heaters can reach temperatures of up to 600°C. A temperature controller, such as a thermostat as well as thermocouple, can be used to control the temperature.

Thermal strip heaters provide optimal heat transfer in forced or free-air heating applications. They are used to heat storage tanks, as a heat source in industrial ovens, and to heat air or other inert gases. They are also used in food warming, heating ovens, packaging and sealing processes, heating laboratory equipment, heating moulds, and a variety of other applications.

How do thermal strip heater work?

Strip heaters are reliable for heating air and various liquids, as well as clamp-on heating of various metals and flat surfaces. But depending on the application, thermal strip heaters usually involve both conductive and convective modes of heat transfer. Power is applied to terminal pins located on thermal strip heaters, allowing current to flow through the heating element. The generated heat is then transferred to the material to be heated. Mica strip heaters use the conduction mode of the heating principle to transfer heat to any metal or other flat surface. Mica strip heater is clamped on to the surface to be heated with the help of bolts. A finned strip heater, on the other hand, uses convection to heat the liquid or gases.

Which strip heater should be used?

The process of selecting a heater is complicated and involves a number of factors to consider. The most suitable kind of strip heater for a particular application may depend on a number of factors. This covers everything, from the highest temperature it can reach to the unit’s safety features and lifespan. Finally, it is important to think about the costs. Here, we’ve highlighted some of the key factors that should be taken into consideration when choosing a strip heater.

Factors considered when selecting a thermal strip heater

  • Physical Specifications: The width and thickness of the strip heaters can be adjusted, but the length is determined by watt density.
  • Sheath material: Galvanised iron and stainless steel are common choices for sheaths as they are unlikely to corrode as well as oxidise.
  • Insulation: To reduce heat losses to the environment, common insulation materials include mica, magnesium oxide, and ceramic materials.
  • Mounting Styles: Thermal strip heaters can be mounted in a variety of ways, but the most common ones are mounting with holes, slots, or cutouts.
  • Electricity outputs and power requirements
  • Operating temperature of the sheath as well as the heating element.
  • Watt density: The amount of wattage that a strip heater can produce per square inch is known as watt density. Watt density must be limited in order to avoid exceeding the maximum sheath temperature when high operating temperatures are required.
  • Lead wire options: insulated lead wires or metal braided lead wires
  • Termination options:
  1. Stud connection
  2. Lead wire connection with terminal box
  3. Lead wire leaving at one side of the heater
  4. Lead wire leaving at top or bottom of the heater
  5. Termination with connector

Based on the above factors, three types of strip heaters can be used and opted for different applications and are manufactured by us:

Mica Strip Heater

Our mica strip heaters are cost-effective heaters with watt densities that are feasible up to 25 W/in2. They are suitable for temperatures up to 300 °C. Their minimum width is 17mm, and their thickness is between 4 and 6mm. Mica strip heater is made up of three sheets of mica: the winding mica, the top mica, and the bottom mica sheet. To see the detailed information about termination options, download our datasheet.

Ceramic Strip Heater

With a possible watt density of up to 30 W/in2, our ceramic strip heaters are made to withstand temperatures as high as 450 °C. I It is similar to a mica strip heater. The main difference is that ceramic is used as insulation in ceramic strip heaters. Their thickness ranges from 9 to 12mm, and their minimum width is 15mm. Both thickness as well as width can be modified according to the customer’s requirements.

  • In addition, we make finned strip heaters, which are identical to mica and ceramic strip heaters. The only difference is that fins made of galvanized iron or stainless steel are attached to the metal sheath, which increases the heat transfer area. Download the datasheet for finned and ceramic strip heaters for more detailed information on them.

Why Marathon is the best for thermal strip heater?

Strip heaters made by Marathon Heaters are reliable flat heaters built to deliver effective heat for many industrial as well as commercial uses. Additionally, we can modify the wattages and voltages of strip heaters as needed. We have certified engineers and sales support staff on hand to help you with your technical inquiries, quotation requests, and orders. Visit our contact page to contact us by phone or email. Due to their unique and adaptable design, thermal strip heaters made by us are effective for the majority of surface heating applications as well as process air heating applications.

Benefits of Strip Heaters

The following are just a few benefits of the thermal strip heaters manufactured by us:

  • Cut-outs or holes enable the installation of temperature sensing apparatus.
  • They can be bolted or clamped to solid surfaces to transfer heat over a large area.
  • High operating temperatures
  • The physical dimensions can be altered to meet customer needs.
  • There are several types of termination available.
  • Uniform Heat Distribution
  • Easy installation and control
  • Easy and economical to install
  • Corrosion as well as vibration resistant


With our own engineering and manufacturing range, Marathon Heaters aims to give its clients high-quality thermal strip heaters for heating surfaces or small areas. With our exquisite range of various electrical heater types, we have been providing industrial heaters for many different kinds of applications. If you have any inquiries, please send an email to, and a member of the team will get back to you shortly as they can.