In any laboratory setting, temperature-sensitive materials such as biological samples, reagents, and pharmaceuticals depend on precise storage conditions. That’s why maintaining the correct temperature in your freezer is critical – any deviation can compromise the integrity of your research and cost your lab time, money, and credibility.

Regular freezer calibration isn’t just good practice—it’s essential for laboratory safety and compliance. But how do you know when calibration is required?

Below are five common signs that your laboratory freezer may be due for professional calibration.

 1. Temperature Fluctuations Beyond Acceptable Ranges

Even brief deviations from the validated temperature range in a laboratory freezer are a serious concern. Lab-grade freezers are engineered to maintain strict, stable conditions, and unexplained fluctuations can signal underlying problems like sensor drift, compressor malfunction, or improper calibration. These variations, even if minor, can compromise sample viability and the integrity of your research.

If your freezer display shows inconsistent readings, verify the internal temperature with an independent thermometer. A mismatch means it’s time to recalibrate or service the unit to prevent costly losses.

2.     Frequent Alarms or Error Codes

Most modern laboratory freezers are equipped with alarm systems that trigger when internal conditions fall outside of acceptable ranges. Frequent alerts can indicate calibration drift. Don’t ignore these warnings—they are your freezer’s way of saying something is off.

Repeated alarms, even when the door is closed and usage is normal, could point to sensor inaccuracies or control system issues that a calibration can fix.

3.     Visible Frost or Ice Build-Up

Excessive frost or ice inside the freezer can suggest temperature instability. This might be caused by poor door seals or frequent opening, but it may also indicate a malfunctioning thermostat or faulty sensor, both of which are revealed and corrected during a professional calibration.

Why it matters: Ice build-up can obstruct airflow, leading to hot and cold spots within the unit, which jeopardizes consistent sample storage.

4.     Extended Recovery Time After Door Openings

After you open the freezer, it should return to its set temperature relatively quickly. If it’s taking significantly longer than usual, the internal sensors or control systems might be out of calibration. This sluggish recovery could compromise temperature-sensitive materials, especially in high-traffic laboratory environments.

Watch for: Recovery taking longer than manufacturer specifications or compared to similar freezers in your lab. 

5.     It’s Been Over 12 Months Since Your Last Calibration

According to industry best practices and regulatory guidelines, laboratory equipment should be calibrated at least once a year. If it’s been over 12 months, you’re not just risking equipment failure—you could also be falling out of compliance.

A missing or outdated calibration certificate is a red flag during audits by the MHRA, UKAS, or other accrediting bodies.

Bonus Tip: Maintain a Calibration Log

You should keep a freezer calibration certificate and service log for each freezer in your laboratory. This helps during audits and ensures traceability. If your records are missing or incomplete, it’s another sign it’s time to schedule a calibration visit.

Next Steps

If you’re noticing any of these warning signs, don’t wait for a costly failure or compliance issue. Schedule a professional calibration service today. Regular maintenance is a small investment that safeguards your research and reputation. Reach out to our friendly team on 01506 463 734 or get in touch using our online contact form here.