I Tested (Almost) Every Temperature Setting on My Fridge to Find the Sweet Spot

Keeping lettuce fresh and preventing a frozen-solid gallon of milk is a delicate balancing act. Maybe you keep the butter in the back. If your refrigerator is going to freeze something, it might as well be a resilient sacrificial offering.

Since I'm not one to waste food, I set about finding my fridge's Goldilocks zone: the setting that keeps everything in the perfect (or as close to perfect as possible) temperature range. What better way than to test the temperatures of various fridge zones on every setting that the machine offers?

Here's how everything went down.

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What temperature should a fridge be?

Before I can determine the best temperature setting for my fridge, we need to know what constitutes a safe temperature for storing food.

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The general scientific consensus is that a refrigerator's temperature should be 40 degrees Fahrenheit (4 degrees Celsius) or below to control bacterial growth without freezing sensitive foods.

Likewise, your freezer should be set to 0°F (minus 18°C) or lower. While you might think that any temperature below 32 degrees F (0 degrees C) is sufficient, there's a good reason to target a lower temperature. This ensures that food stays frozen even when you open the freezer, add unfrozen items and experience short power outages. Understandably, items also freeze more quickly in lower temperatures, which can reduce ice crystal formation.

I ran the tests using real-world conditions

When storing food in your refrigerator, ensure it falls within the safe temperature range for food storage.

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When testing the fridge temp settings, I didn't unload all of my food, though I did move more sensitive items -- fresh produce, eggs, and some glass jars -- into temporary coolers for colder tests. Likewise, I couldn't keep items outside the fridge or keep warmer temp settings for longer than two hours.

This all required me to keep my tests short. Every time I opened the door, checked the temperature or changed a setting, I affected the test. These inconsistencies, while distressing to my scientific mind, created findings that align more closely with real-world conditions where you might open a packed fridge multiple times an hour.

Fridge thermometers make these tests possible

An abundance of fridge thermometers and smart sensors helped with my test.

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As with any test, I needed a way to measure and track temperatures over time. For this test, I used three different kinds of temperature sensors: ThermoPro Refrigerator Thermometers, Hatusoku Digital Thermometer with External Sensor and the recently announced Ikea Timmerflotte smart temperature and humidity sensor.

ThermoPro is the most suitable option for most people because it can be hung from shelves or flipped back into a helpful stand. The built-in light also helps you see the LCD (display) in low lighting -- like my freezer, which has no interior light.

Hatusoku's long temperature probe makes it a great option for a thermometer that you can stick on the outside of the fridge for at-a-glance checks. Still, the probe is extremely sensitive and almost always reacts when I open the door.

ThermoPro and Hatusoku can track minimum and maximum temperatures, allowing you to see if the temperature leaves the safe zone or how much it fluctuates when the fridge compressor is running.

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Because it's so sensitive, the min/max setting isn't as useful. Consider waiting a few minutes after a cooling cycle before checking the temperature. You also need to contend with an additional wire when placing the probe.

Timmerflotte made my testing arsenal after I floated the idea to a company representative. They were just as curious to see how the sensor performed in the fridge as I was. Still, a developer with the company said the sensors could handle the internal temperature of my fridge, but that the metal might interfere with its connection to the Dirigera smart hub. (Fortunately, I had no connection issues during my test.)

I liked that I could press the front of the Ikea sensor to show its current temperature and humidity without my phone.

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Because it's a smart temperature sensor, Timmerflotte provided me with real-time temperature measurements without requiring me to open the fridge. Ikea sent enough sensors so that I could track the temperature in both the front and back of the fridge, which was incredibly helpful for finding the perfect setting. The Ikea Home Smart app didn't have a way to track temperature over time -- I couldn't spot trends outside of my manual checks.

However, I should note that the minimum temperature for Timmerflotte was around 14 degrees F (minus 10 degrees C), so it was unable to track the temperature of my freezer. It also turned off after about 12 hours because freezing temperatures and Alkaline batteries don't get along.

How I tested my fridge temps: limitations and caveats

My refrigerator uses a simple dial thermostat to control both the fridge and freezer. The dial lists numbers 1 through 9, with 9 being the coldest setting. Starting with 1, I measured the temperature for at least 20 minutes (often longer with colder settings) to allow the temperature to even out after each compressor cycle. 

My refrigerator uses a simple dial thermostat to control both the fridge and freezer. The dial lists numbers 1 through 9, with 9 being the coldest setting.

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Here's the rub: My results are unique to my home and fridge. 

• Although GE still makes my fridge (Model GTR15BBMRWW), it's an old model with a likely manufacture date of April 2001. The owner's manual even recommends setting the temperature control dial to 5 and adjusting from there.
• I have a lot of food in my fridge due to Thanksgiving preparations. With such a large thermal load, it takes a considerable amount of time for the temperature to stabilize after adjustments are made. A high food load also blocks airflow during the cooling process, resulting in cold and hot spots.
• The average temperature of my kitchen during these November tests was about 64 degrees F, which affects how long the fridge runs.
• Opening the door frequently during testing certainly affected the results.
• I usually use a slightly colder setting in the summer to keep foods in the safe zone, and GE's advice reflects this. Even then, I only put items that are safe to freeze in the back of the fridge, just in case.

Finally, my measurements were more consistent and reliable in the fridge than in the freezer, which fortunately stayed below 14 degrees F (minus 10 degrees C) throughout the test. (I mostly chalk this up to forgetting to photograph refrigerator thermometer readings for Levels 2, 3 and 4.) However, the freezer thermometer wasn't consistently at 0 degrees F (minus 18 degrees C) or below until I reached Level 4.

My test results and takeaways

I kept both thermometers in the back of the refrigerator to get consistent readings from both.

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Ultimately, Level 5 (actually slightly below this) was the only one that kept all of my food within the target range. The front, back and freezer all met the aforementioned food safety guidelines. The other settings either froze items in the back or kept front items too warm.

You can see why I canceled the test after Level 8, which put the entire fridge at or below freezing. This level also caused the compressor to run continuously for almost an hour before shutting off. 

So, I couldn't risk spending at least as much time trying to hit Level 9, which I suspect could turn my entire fridge into a freezer -- even if the fridge compartment doesn't quite hit 0 degrees F. (I don't have enough cooler space to hold a fridge's worth of food.)

For my fridge, Level 5 is right in the middle, which is likely what the manufacturer intended when curating the various settings. From a user standpoint, I found that impressive. My biggest takeaway from the results is that setting the fridge to a colder temperature isn't necessarily better, which is sometimes my instinct when I percieve that food is spoiling too quickly. 

A simple set of fridge thermometers can help you hit your target temp.

ThermoPro

Should you test the temperature of your own fridge?

If your food is consistently spoiling or freezing without explanation, it could be because your settings aren't calibrated properly. You may not even know which setting is intended to hit the target fridge temp of 40 degrees F (4 degrees C) or below. If that's the case, running a similar test on your own fridge would be wise. 

I recommend getting a set of fridge thermometers as I did. I consider them essential for simple fridges like mine, which use a dial thermostat that doesn't display the actual temperature.

While many fridges have a digital thermostat with your target temperature, an independent fridge thermometer's flexibility can help you learn more about your fridge. For example, you'll be able to move the thermometer around to find cold spots or track temperatures during a power outage.