Preventing Condensation in Electrical Enclosures

Condensation is the act of a substance transitioning from its gas form to its liquid form. Condensation is a common phenomenon in nature, and we have all seen condensation of water on a bathroom mirror or on the surface of a glass holding a cold drink. Condensation occurs when the temperature of a surface drops below the dewpoint temperature – a dynamic, not static, temperature point that depends upon the interplay between humidity and ambient temperature.

While condensation may look beautiful in the form of the morning dew, it can wreak havoc with valuable electronic equipment. This moisture can cause rust, corrosion, short circuiting and electric shock – proving at the least to be expensive and at the most to be dangerous.

How to prevent condensation in Electrical Cabinets?

Pfannenberg, which specializes in providing solutions for thermal management systems, has its finger on the pulse of how to prevent condensation in enclosures – such as electrical cabinets – that need to be kept free of moisture.

The first tip has to do with controlling the enclosure temperature. “Traditionally, in an enclosure, we are going to recommend keeping the temperature somewhere between the 85-degree and 95-degree Fahrenheit mark,” says Pfannenberg sales representative Adam Wells. “That generally represents a comfortable place for the electronics as well as for keeping it warm enough to avoid that dew point temperature.”

Pfannenberg experts also recommend using dehumidifiers in enclosures with high humidity or that are not completely sealed to prevent condensation. Typical dehumidifiers use a desiccant or some type of silica gel to wick moisture out of the air. Air conditioning units can also act to collect any condensate that may build up on the internal side of an enclosure and be dispersed into the environment with the help of a condensate evaporator.

Air conditioning units can also act to collect any condensate that may build up on the internal side of an enclosure and be dispersed into the environment with the help of a condensate evaporator.

Hygrostat FLZ 600

An unusual device known as a hygrostat can also be used to monitor the humidity levels in an enclosure. Originally made of horsehair, hygrostats are now made with synthetic hairs that expand and contract depending on the amount of water in the air. The same can be seen happening in human hair – for example when hair gets curlier on a humid day.

Another way to open the door to condensation is, literally, by opening a door. Pfannenberg sales representative Chris Marlow explains, “If you have an enclosure, and you have a cooling device in there, and you don’t turn off the device when you open the doors, you can get condensation build up inside that enclosure just from exposing air to that decrease in temperature.”


For more information on how to protect valuable electric equipment from condensation, visit Pfannenberg’s lively webinar discussion on this topic at

3 Solutions to Protect your Electrical Enclosures From Condensation and Humidity

What is condensation?

Formation of condensation is one of the biggest dangers for electrical enclosures. Condensation is caused by hot, humid air coming into contact with a colder surface than the air dew point.

With Spring’s typical variable weather conditions, outdoor enclosures are even more exposed to the risk of condensation. Condensation can also occur indoors if the humidity is too high.

When the humidity is high is does not take a large change in temperature to cause condensate to form inside the cabinet.

How to prevent condensation?

The most efficient solution is to combine Filterfans® and Heaters with control devices such as Hygrostats and Thermostats. Fan Heaters are typically used in outdoor applications where ambient temperature can threaten sensitive electronics. Radiant Heaters are often used to reduce humidity and control condensate within the enclosure.

1. Filterfans® + Rainhoods

Filterfans® are the ideal solution for clean, non-hazardous environments with an acceptable ambient (outside the enclosure) temperature range.

Designed for use with standard Filterfans®Pfannenberg’s new Rainhoods (Patent Pending) protect your application from harsh environments like rain, water spray, snow or fluids from being drawn into the enclosure.  This product feature a robust design rated to NEMA TYPE 3R/4/4x and IPx6 when used with Pfannenberg Filterfans®.

Adding a Heater to your Filterfan® + Rainhood solution will ensure a proper humidity control. This combination is the optimum solution for the economical and energy efficient cooling of electrical enclosure components.

2. Fan Heaters

Pfannenberg Heaters prevent condensate build up and therefore protect against corrosion.

Compact fan heater with thermostatFan HeaterMini radiant heaterThe PFH-T Fan Heaters with Thermostat are designed to protect electronics from the effects of low temperatures such as corrosion, freezing or condensation, which can damage critical components within a control enclosure.

The PRH-M Mini Radiant Heaters are ideal for small outdoor enclosures, preventing condensate formation.

The FLH Heaters are ideal for use in larger electrical enclosures.

3. Thermostats / Hygrostats

Industrial ThermostatHygrostat FLZ 600

Pfannenberg’s Hygrostats allow you to effectively control the humidity level inside the enclosure. These devices are used to start the heater or filterfan® if the predetermined humidity threshold is reached.

When combining a Pfannenberg Thermostat with a Filterfan®, the fan can be controlled to turn on and off based on the temperature inside the cabinet.

The benefits to this combined system are:
• Extended fan life.
• Reduced energy consumption.
• Reduced consumables and maintenance.

As a system; Filterfans, Heaters, Thermostats and Hygrostats will ensure that the environment within the enclosure is ideal for the performance and service life of the critical electronics.


Control Enclosure Temperatures in a Food & Beverage Manufacturing Plant

Controlling enclosure temperature is crucial in the food and beverage industry.  If the temperature is too warm or too cold, condensation and higher risks of contamination arises. 

Pfannenberg’s Heaters, Thermostats & Hygrostats detect and keep ambient conditions above dew point to avoid the harmful effects of condensation on your electronics and products. They can be used as standalone or in partnership with our other Thermal Management solutions specifically our Filterfan® and Cooling Unit product lines.

  • Thermostats are used for alarming, fan control and heater control
  • Hygrostats can control humidity levels within enclosure when used with small heaters
  • Heaters are available for cabinets in cold storage areas as well as for condensate management

For over 60 years, Pfannenberg has been helping to cool and maintain temperatures for your electronics.


Topics: Thermal ManagementNorth AmericaHygrostatsThermostatsHeatersFood & Beverage