How we tested
We’ve all been there: You’re hungry and eager to eat, but your food is taking forever to come up to the right temperature. You open the oven or grill every few minutes, insert your thermometer, and pray for that magic number to display. Soon enough, your beautiful steak or side of salmon is riddled with holes—and still not done. It’s a double-edged sword: The more you open the oven door or lift the grill lid, the longer your food will take to cook, but you don’t want to miss that elusive perfect temperature.
Our winning clip-on probe thermometer, the ChefAlarm by ThermoWorks, helps with this problem. It features a probe that is connected by a thin wire to a base that sits outside the grill or oven. The probe is inserted into the food you’re cooking and the base displays the temperature readout, allowing you to monitor temperature without opening the oven door or lifting the grill lid. However, this thermometer has a limitation: You can read the temperature only when standing next to the stove or grill. Remote-probe thermometers, which are similar in design and operation to clip-on probe thermometers, get around this restriction by also transmitting their temperature data to portable receivers.
Before we started testing, we learned that there are two types of remote-probe thermometers: pager-style and smartphone connected. Pager-style thermometers send their temperature data via radio frequency from the base to a handheld monitor (much like a walkie-talkie or baby monitor). Smartphone-connected thermometers rely on Wi-Fi or Bluetooth (which are not the same—more on that later) to transmit temperature data from the base to an app on your phone.
To find the best remote-probe thermometer, we tested a mix of models, including two pager-style and five smartphone-connected models. Of the smartphone-connected thermometers we tested, four use Bluetooth and one uses Wi-Fi. Two of the Bluetooth thermometers were “smart-probe” thermometers. Instead of wired probes that plug into bases that sit near the stovetop, oven, or grill, the probe itself transmits the temperature data wirelessly via Bluetooth to your phone—no base required.
All the thermometers were priced from about $43 to around $230. We used each to monitor pork butt on a gas grill for 4 hours, hamburgers quickly cooked on the stovetop, and whole chickens roasted on a charcoal grill for 1 hour. During each test we walked up to 1,000 feet from the probes, up and down stairs, and behind walls, frequently checking the connection. We also used them in the dark, in the rain, and in an area with limited cell service.
Pairing the Thermometer Base with Receiver or Smartphone
Setting up the two pager-style thermometers was a breeze. The bases connected to the probes came automatically paired to the handheld receivers. Conversely, we had to pair each of the smartphone-connected thermometers with our phones via the specific model’s app, which we had to download first. For some models, this was straightforward—simply pushing the buttons on their receivers paired the thermometers with our phones. However, other models required many extra steps that were confusing or cumbersome. Some of the Bluetooth and Wi-Fi thermometers took multiple tries to pair properly, and pairing one involved nearly an hour of rereading the instructions and searching the Internet for answers. The included instructions were vague and poorly translated from French (even though this model is widely available in the United States), and we eventually figured out that we had to position the probe close to the lower portion of the base to initiate pairing—an unusual extra step that wasn’t clear in the manual and that none of the other thermometers required. The two wireless probes also had to be charged for at least 4 hours before we could even pair them with a phone (not a deal breaker, but disappointing). While these probes work for hours after being charged, you do have to periodically plug them into an outlet for charging. Ultimately, we were able to pair all the probes and bases with their receivers, but not without significant frustration.
Checking the Connection
With all the models finally connected, we started testing how easy it was to set their alarms and how well they maintained a connection. First up was cooking the pork butts on a gas grill. We distributed the probes of all the models among three roasts called for in the recipe and set the thermometers to alert us when the roasts reached 210 degrees. We then walked up to 1,000 feet in various directions away from the grill, venturing up and down stairs and behind thick concrete walls and metal barriers, all while continuously checking the connections.
The Bluetooth thermometers were the first to lose connection. One stopped transmitting a reading at just 25 feet, and three others followed suit between 150 and 200 feet. Pager-style thermometers had a moderate range of about 300 to 450 feet in open air. Only the Wi-Fi-connected thermometer continued to transmit temperature readings no matter how far away we were from the grill; it lost connection only when we went into an area with no cell phone or Wi-Fi service. All these different thermometers, whether pager-style or smartphone connected, rely on radio frequencies to transmit temperature data—but it turns out not all radio connections are the same.
The Difference Between Radio, Bluetooth, and Wi-Fi
Radio frequencies are electromagnetic waves that connect one device to another and are used to transmit data to all kinds of receivers, such as the radio in your car, cell phones, baby monitors, and remote garage-door openers. Bluetooth and Wi-Fi are modern ways of transmitting data, but they still use good old-fashioned radio waves. Bluetooth uses radio waves to connect devices such as a thermometer base with a smartphone. As long as the phone you’re trying to pair with a device is within a certain distance, you’ll have a connection. The plus side is that Bluetooth is not dependent on Internet or cellular service, so the connection continues to transmit signals in cellular dead zones.
Unlike Bluetooth, Wi-Fi relies on an Internet connection, usually supplied by a router or cellular data. As long as your phone is connected to the Internet, you’ll be able to read the temperature on your Wi-Fi-connected thermometer, no matter how far away you are.
We found that all the thermometers transmit at the common frequency of 2.4 gigahertz. So what was causing such a drastic difference in the range of each thermometer? Other factors that influence the range of a radio connection include the size of both transmitter and receiver antennae, the transmission power of both devices, and the material and type of antenna. It’s clear that these variables were impacting the range of the thermometers. The shortest range came from the two Bluetooth smart-probe thermometers; all their electronics, including their antennae, are crammed into the tiny space at the end of the probe, likely reducing the reach of their radio waves. Conversely, thermometers with bases have much more room for a larger and better-powered antenna, and we found their ranges to be significantly longer. The most consistent connection came from the one Wi-Fi-connected thermometer. As long as we had Wi-Fi or cell service, we could read the temperature. That said, when we tried the Wi-Fi thermometer in a zone with no Wi-Fi or cell service, it switched over to Bluetooth and its range was comparable to other Bluetooth devices—100 feet or so. The wattage of Bluetooth devices is regulated by a standards organization and can transmit at a maximum of only about 100 milliwatts—about 100 feet in practice, consistent with the range we saw for most of the Bluetooth thermometers we tested. Pager-style thermometers don’t have the same power restrictions as Bluetooth devices, and we found that they had a moderate range of 300 to 450 feet. While this wasn’t quite as far as the Wi-Fi model, we found that the pager-style models struck a good balance of connection range and usability (no wrangling with glitchy apps required).
Evaluating Ease of Use
Many of the apps for the smartphone-connected thermometers were buggy and confusing to navigate and didn’t give clear alerts when we went out of range or when the food reached the right temperature. There was also another drawback: Most have preset temperatures built in for various cuts and types of meat, and these preset temperatures are often based on recommendations by the U.S. Food and Drug Administration that we’ve found result in overcooked food. Trying to set our own customized temperatures proved especially difficult—one thermometer would let us enter a maximum of only two digits for a custom temperature, so we had to convert all our Fahrenheit temperatures to Celsius to use that function.
The apps also had an interesting quirk when they inevitably lost connection: They didn’t always automatically reconnect when we were back in range. Sometimes we had to reopen the phone’s Bluetooth settings and re-pair the probe. One was so glitchy that every single time the screen lock on our phone came on, the thermometer lost connection. We had to remove the probe from the food, return it to its base, and re-pair the thermometer to our phone.
Pager-style thermometers were much simpler to use. Our favorite had big, clear buttons and a large, bright display that made setting and reading the temperature a cinch. The alarm was loud, and it beeped to let us know when we had lost connection from the base. Best of all, it automatically reconnected when we walked back into range.
Homing In on Accuracy
While we found a few remote thermometers that maintained stable connections, we also had to test the thermometers’ accuracy—since a thermometer should be, above all, accurate. In addition to using the thermometers while cooking pork, burgers, and chicken, we conducted a series of accuracy tests. We used an immersion circulator—a device that heats water to a very precise temperature for sous vide cooking—to warm a water bath to 130, 180, and 212 degrees Fahrenheit. We hooked up the thermometers to the water bath and compared their readings to a lab-calibrated reference thermometer. All but one of the thermometers was accurate to within 1 degree (some of the thermometers give decimal readouts, but others don’t). The inaccurate thermometer was off by up to 7 degrees, which could make the difference between a medium-well and well-done steak. We tried a second copy and it was off by 3 degrees—not as egregious, but less accurate than we prefer in a thermometer.
We also tested how rapidly the thermometers could relay temperature information from their probes to their receivers by dunking the room-temperature probes in ice water three times and timing how long it took for the receivers to read 32 degrees. The reading times ranged from an average of 5 seconds (on par with the ChefAlarm) to an average of 25 seconds. While you’re unlikely to overcook your food in 25 seconds, we preferred models with a rapid relay time of 10 seconds or less, especially when we’re using a thermometer for very temperature-sensitive tasks such as grilling fish.
The Best Remote-Probe Thermometer: ThermoWorks Smoke 2-Channel Alarm
Ultimately we chose a pager-style thermometer as our top pick. The ThermoWorks Smoke 2-Channel Alarm was accurate to within 0.1 degrees of a reference thermometer and maintained a stable connection across 300 feet of open space—a reach equal to the length of a football field. We found that it also maintained connection when we went up or down stairs or behind most walls, though the range was a bit shorter when multiple walls were in the way. The receiver paired instantly with its base when we took it out of the package, and large, bright, backlit displays on both the base and receiver clearly display the temperature reading. The base is magnetic and can be attached to an oven door or a grill lid, and it has a kickstand for stability when sitting on a side table or counter. The receiver comes with a lanyard so that you can wear it around your neck (like our top-rated wearable timer). Whenever we lost connection the receiver beeped loudly (a button press silences the alarm), and it automatically regained connection when we were back in range. It can read up to 572 degrees Fahrenheit, which makes it even more versatile because you can use it as a traditional thermometer for candy making or deep frying, too.
A note: While this model is a pager-style thermometer, ThermoWorks sells a model called the Smoke Gateway that can convert it to smartphone-connected thermometer. We tried it and found that it was difficult to pair and that the app was glitchy. If you prefer a smartphone-connected model, we can recommend the Nutrichef Bluetooth Wireless BBQ Grill Thermometer. Its range is 200 feet in open air—plenty of distance for most homes—and its temperature readings were accurate to within 1 degree.
- Seven models priced from about $43 to about $230: 2 pager-style models and 5 smartphone-connected models
- Set up all models according to manufacturers’ instructions and pair smartphone-connected models to iPhone
- Monitor temperature of pork butt on gas grill for 4 hours
- Track temperature of burgers cooking on stovetop
- Monitor temperature of chicken roasting on charcoal grill for 1 hour
- During all tests, walk away from base until receiver loses connection, then walk back toward base and check for reconnection
- Walk behind walls, up and down stairs, and in areas with low cell and Wi-Fi service, checking connection
- Test temperature accuracy at 130, 180, and 212 degrees Fahrenheit
- Test reading display lag time by dunking room-temperature probes in ice water and time how long it takes for receiver to register 32 degrees
- Leave out in rain for 2 hours
- Try to read display in darkness
- Clean probes after each test
Setup: We evaluated how easy the probes and bases were to set up and pair with their receiver or relevant apps.
Connectivity: We noted the range and consistency of each thermometer’s connection to its receiver or a smartphone and its ability to regain connection when back in range.
Ease of Use: We evaluated how easy it was to set and silence alarms and set custom target temperatures, how clear and legible the displays were, and how intuitive the apps were to operate.
Accuracy: We measured the accuracy of the thermometers by comparing their readings at different temperatures to a lab-calibrated reference thermometer. We also tested probe response time by dunking room-temperature probes in ice water and timing how long it took for the receiver to read 32 degrees.