Preventing Condensation in Environmental Chambers

How do you prevent condensation in an Environmental Chamber?

As air cools, it contracts—creating a vacuum-like effect. When an environmental chamber pulls down in temperature, this can draw outside room air into the workspace. That incoming air often contains moisture, which can freeze on the cooling coil. Upon reheating, this moisture vaporizes and may condense on the test product—potentially affecting test accuracy and product integrity.

To reduce the risk of condensation, a Dry Air Purge or Gaseous Nitrogen (GN2) purge can be used. By purging the chamber with either medium and maintaining slight positive pressure inside the workspace, moisture infiltration is minimized. Both dry air and GN2 have extremely low moisture content, helping to keep the chamber environment consistently dry during operation.

Humidity Chamber Condensation Management

In humidity chambers, condensation can also occur when humidity and air temperature rise faster than the temperature of internal surfaces or the test product. To prevent this:

• Raise the air temperature first and allow the chamber walls and product to stabilize.
• Once thermal equilibrium is reached, then increase humidity levels.

This approach ensures that the dew point of the chamber air stays below the temperature of surfaces, thereby preventing moisture from condensing on the product or chamber walls.

For optimal results, it's recommended to run one or more characterization tests to determine how long it takes the largest thermal mass—whether the product or chamber wall—to reach thermal stability.

Advanced Control for Precision Testing

CSZ EZT controllers support advanced features such as cascade control and guaranteed soak capabilities. A separate sensor can be placed on the product to monitor its temperature independently. The controller can be programmed to trigger specific events—such as ramping humidity—only after the sensor confirms that the product temperature is within a predefined range of the setpoint. This ensures precise environmental transitions and protects sensitive test samples from condensation or thermal shock.