Sad businesswoman working late at night in the office and freezing, she is wearing a coat and hat

Which is Better? Resistive Heaters vs. PTC Heaters

STEGO USA is based in Atlanta, Georgia, smack in the middle of the Southeastern U.S.  It’s March, and spring is right around the corner. Many employees have been using individual office heaters for the winter season to stay comfortable. Facilities managers have strict regulations on the types of heaters that may be used, as there is a risk of fire or high power draw inside an office building. 

We have personally experienced this hazard in our own office building. One of our office employees is cold-natured and uses two space heaters to keep her office warm. Recently, on a very cold day, between the draw of extra space heaters and our office thermostat, it tripped our local circuit, cutting power to the heaters, the computer monitors, lamps, printers, etc. for our section of the office. Until someone from maintenance could reset the panel, we could not work.

In electronics enclosures, designers include heaters to avoid temperature drops inside the cabinet, preventing the formation of condensation.

Condensation, if not controlled, can lead to safety or reliability issues for the electronics contained within.

Reliability is sometimes better stated as downtime avoidance – kind of like our office example above. As users, we expect uptime – and so do your customers.

There are many choices in cabinet heater technologies, but the two most prevalent are Resistive and PTC. Both accomplish the same task but in different ways.

Resistive heating is the process of converting electricity into heat energy. Fixed wattage heaters are typically manufactured with resistive wires or etched circuits. A toaster is a great example of resistive heating where the wire in a fixed wattage heater must reach a very high temperature to dissipate the desired temperature across the area to be heated. A thermostat or temperature sensor is used to keep the heater from overheating. This single point sensing method remains one of the crucial problems with fixed wattage heaters.

Any sensor or circuit failure can lead the heater to reach dangerously high temperatures, thus becoming hazardous to the user. Furthermore, the heater will continue to draw power if the temperature sensor does not detect the malfunction.

Other potential failure modes associated with fixed wattage heating include hot spots, broken conductors, and overheating.


STEGOs Touch safe PTC heater
The CSF 060 is a touch-safe PTC heater for use in enclosures.

Positive Temperature Coefficient (PTC) heaters are self-regulating heaters that run open-loop without any external diagnostic controls. While traditional fixed-resistance heaters employ wires and coils to generate heat, PTC heaters use conductive inks printed on thin, flexible polymer-based substrates.

Scoring high on reliability and efficiency, PTC heaters are ideal for products that require safer, faster, and more uniform heating.

The material properties allow the PTC heater to act as its own sensor, eliminating the need for any external feedback controls. As a result, the heater inherently removes the risk of overheating.

Electronics cabinet designers have multiple competing priorities – uptime, cost efficiency, risk mitigation, and others. By selecting PTC heaters, you’re picking the right solution for you and your customers, reducing your headaches in the short term, and in the long term. 

Designing complex electronics that perform perfectly outdoors is, well, complex. At STEGO, we believe that protecting those complex projects from extreme climates should be the simplest part of your design. That’s why we use German engineering to create the highest quality thermal management components to protect your designs from anything Mother Nature throws at it. We’ve been pioneering Thermal Management for over 40 years now. With STEGO parts installed, you can rest easy that your complex design is reliably protected for the long haul.