Freezer & Refrigerator Thermometers

Fridge Thermometers: What You Need to Know

Although many refrigerators have built-in thermometers, using a separate refrigerator-freezer thermometer is important to verify the accuracy of temperature readings and identify potential hot or cold spots within a cooler. Monitoring temperatures with the use of a refrigerator-freezer thermometer is critical to ensuring stored food remains safe for consumption. Temperatures can vary significantly across different parts of a cooler's interior depending on its setup and what air distribution equipment it uses, so it's important to ensure all areas stay within the required temperature zone. In some places, health code regulations even mandate the use of multiple walk-in cooler thermometers.

Available in a range of styles and sizes, refrigerator temperature gauges can be analog or digital, and may have a tube, dial, LED display, remote probe, or combination of features. No matter which style, all refrigerator and freezer thermometers are designed for safe use in food storage areas and provide a way for restaurant operators to verify the temperature of their reach-ins and walk-in coolers.

Common Questions About Freezer & Refrigerator Thermometers

Where's the best place to put a fridge thermometer?

Refrigerator-freezer thermometers should always be placed in the warmest spot, typically just inside the door of the refrigerator. For larger refrigerated spaces, it's best to have multiple walk-in cooler thermometers placed around the unit's interior. One thermometer should be placed close to the door, and others spaced evenly around the refrigerator's interior. Sections that are frequently accessed are also good options for placement of a walk-in cooler thermometer.

Some refrigerator-freezer thermometers are designed with hooks or clips so they can be attached to the edge of a shelf or rack, while others have flat bases to keep them upright when they're placed on a shelf or tray. Some commercial refrigerator thermometers even feature suction cups for attachment to vertical surfaces. To avoid opening and closing the cooler's door too often, a remote or wireless fridge thermometer is a good option. These types of thermometers use a probe placed inside the fridge or freezer to measure the temperature, while a dial or screen attached to the refrigerator's exterior displays the temperature readout in a highly visible spot.

It's important to consider more than just the size and style of a refrigerator or freezer thermometer. Where it needs to be placed for maximum visibility and how it'll be installed are also important factors to determine which type you'll need.

What's the most accurate type of refrigerator thermometer?

Determining which type of refrigerator or commercial freezer thermometer to use depends on an establishment's specific needs, such as the type of product being stored, level of traffic the cooler receives, and the employees who'll be using the thermometer.

Digital refrigerator thermometers are typically very accurate and easy to read, making them a popular choice, but they also require occasional battery replacement to keep them functioning. Because digital refrigerator thermometers use a device called a thermoresister to measure temperature, they're capable of very precise readings and don't contain any potentially toxic liquids.

Analog options, such as tube and dial thermometers, don't require any connection to a power source or battery to function. However, they can sometimes be more difficult to read than a digital option and aren't as precise. These types of refrigerator-freezer thermometers often feature a color-coded design that eliminates confusion among staff when interpreting the thermometer's reading, especially for individuals who may have difficulty recognizing English language numerals or who haven't memorized HACCP compliancy parameters.

Both analog and digital refrigerator thermometers feature styles that can be calibrated to ensure ongoing accuracy during extended use, but this varies from model to model.

Note: For refrigerators where medicine and vaccines are stored, standard refrigerator-freezer thermometers aren't the best choice. In scientific and medical applications, thermometer probes are sometimes placed inside a cup of water, oil, or glycol to simulate product temperatures more closely, so a thermometer with a temperature probe and data logger would be a better choice.

Will a regular thermometer work in a refrigerator?

Refrigeration thermometers are made differently than other types of thermometers, because they'll be used around food and have to withstand rough and tumble use in fast-paced kitchens.

Thermometers designed for oral use, for example, are likely to be made with mercury – which can be highly toxic if the thermometer breaks and the mercury is released – making them unsafe for foodservice applications. Most other thermometers are no longer made with mercury, but they may contain other potentially toxic liquids or be made of glass, which is very dangerous if it gets broken in any food-adjacent area. Digital fever thermometers don't contain mercury or other liquids, however they often use button cell batteries that can cause sickness or injury if swallowed.

It's important to consider how a thermometer is made, as well as its durability, before placing it inside the refrigerator. In order to comply with HACCP food safety guidelines, a thermometer designed specifically to work inside a refrigerator or freezer is the best choice.

How do I calibrate a refrigerator-freezer thermometer?

Not all refrigerator-freezer thermometers can be calibrated, so first it's important to be sure that your fridge thermometer has this feature. If it's a tube-type thermometer that uses liquid to measure and display the temperature, you won't be able to calibrate it; however, you should still periodically check to make sure the thermometer is maintaining an accurate reading. A dial refrigerator thermometer will usually have a calibration nut that can be manually adjusted, whereas a digital refrigerator thermometer will typically use a reset button or screw instead.

The simplest way to calibrate a fridge or freezer thermometer is with the freezing method. With this method, you'll need to place the thermometer's sensitivity probe in a cup or bowl filled with crushed ice and water. Wait for the thermometer to finish adjusting, and then check the display temperature, which should be 32 degrees Fahrenheit or 0 degrees Celsius. If the display temperature doesn't match, you can adjust the calibration nut on a dial thermometer until it does, or initiate a reset if the thermometer is digital.

Any method of calibration may require you to remove part of the thermometer's face, so it's important to always read the instructions for your specific refrigerator-freezer thermometer and check with the manufacturer first before trying to calibrate the unit.