By Tony Carrick, Glenda Taylor
Updated on Feb 16, 2024 5:55 AM EST 2 wire pt100 temperature sensor
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Between trying to maintain the proper humidity in your great room, monitoring the temperature in your greenhouse, or just tracking climate conditions in your home, an indoor thermometer is a valuable tool. Modern indoor thermometers feature digital displays, can track and store data, and can be used as smart devices that send alerts when air quality moves beyond preset parameters.
With so many indoor thermometers on the market, we wanted to know which ones offered the greatest benefits, so we decided to test them ourselves. We also talked to an HVAC professional to get their expert advice on what specifically to look for. Then we purchased the top-rated models in a variety of categories and checked out all their features, evaluating for accuracy, simplicity, and durability.
Ahead, learn what to look for when shopping for the best indoor thermometer for a home, and find out how the following products earned a spot on our lineup.
Before getting our hands on our indoor thermometers, we interviewed Brad Roberson, the president of Aire Serv, a Neighborly company that provides HVAC services nationwide. He says that “indoor thermometers are not the same as HVAC thermostats. Some things to look for when choosing an indoor thermometer are thermometers with clear and easy-to-read displays, built-in humidity sensors, temperature alarms, and compatibility with smart home systems.” He added that “monitoring indoor temperature helps with energy efficiency and proper temperature control helps maintain optimal humidity levels.”
In addition to this expert advice, we considered several other criteria when selecting the best indoor thermometers for our hands-on tests. Our list included indoor thermometers that sync with a smartphone for remote monitoring, making them ideal for greenhouses, wine cellars, humidors, and animal enclosures. We also tested simple units that weren’t wireless but allowed us to see the temperature and humidity at a glance.
Accuracy is crucial when selecting an indoor thermometer, and the picks that earned a spot in this lineup all had a margin of error of 1.5 degrees or less compared with other models we tested. To determine the most accurate readings, we placed all the indoor thermometer units side by side in the same room and compared the readings. We determined accuracy when several units displayed identical temperature and humidity readings. For units with outdoor reading modules, we compared the temperature with that of our professional home weather station.
In addition, we tested every function available on each unit. We downloaded apps for Wi-Fi and Bluetooth models and noted how easy (or complex) it was to configure them. We scored each indoor thermometer using a rubric and awarded points during the testing phase. At the end of the testing, we added the points and used them to help determine the specific awards for each of the models that excelled.
In testing this lineup of the best indoor thermometers, we primarily sought units that gave accurate readings for indoor temperature and humidity. We also looked for easy-to-read displays, as well as apps that synced seamlessly with Wi-Fi and Bluetooth (when applicable). Some models reviewed here are manual, while others send alerts to smartphones to report humidity and temperature changes. The following products offer various functions, but each excelled in our hands-on tests and we’re confident that they’ll perform well for the buyer, too.
Precision is critical when it comes to an indoor thermometer, and AcuRite’s manufacturer claims this thermometer has a narrow 0.5-degree range of error, with data updated every 10 seconds. This model requires calibration, which involves pushing a series of buttons, but this only took us a few seconds and then the thermometer was good to go for testing.
Though we couldn’t determine the exact degree of accuracy for all the thermometers tested, we arranged them all side by side in the same location and then compared the readings. The AcuRite gave a near-identical reading to most of the other thermometers, so we concluded it was highly accurate.
We used the same standard for testing accuracy with humidity readings. In addition to being consistent, the AcuRite also stores high and low readings for 24 hours, showing us how much the temperature and humidity fluctuated.
This model also provides a humidity percentage and a gauge that lets users know if the air comfort level is Low, OK, or High. The large numbers are easy to see—even from across the room. We especially liked the magnets on the back of the AcuRite, which allowed us to put the thermometer on the refrigerator, where we could monitor the temperature changes in the kitchen that resulted from cooking and baking. Overall, we deem this thermometer from AcuRite worthy of a kitchen or living room with its accurate humidity and temperature readings.
Get the AcuRite indoor thermometer at Amazon, Lowe’s, or Cabela’s.
The ThermoPro provides all the information needed to monitor indoor temperature and humidity at an affordable price. While this small model lacks bells and whistles, it displays accurate temperature and humidity readings. We liked that we could choose between its easel-type stand or put it on the fridge via its magnet backing. It can also be hung on a nail on the wall.
Its 2-inch screen shows the temperature and humidity and features numbers large enough to read from across the room, though it lacks a backlight for nighttime visibility. An emoji indicates dry, wet, or optimal comfort with a smile or frown, but that display is so tiny we had to get right up close to the unit to see it.
The ThermoPro can also take readings within a tenth of a degree, and it refreshes every 10 seconds. The TP49 uses one AAA battery (included). All in all, we found this to be an accurate and unobtrusive indoor thermometer at an attractive price.
Get the ThermoPro TP49 indoor thermometer on Amazon or at The Home Depot.
At first, it was hard to believe that the SensorPush is a thermometer hygrometer—the mini module looks more like a keychain fob, which can be hung from a chain or cord if desired. The SensorPush has no visual display, but it transmitted ample in-depth data to our smartphones via Bluetooth.
We downloaded the SensorPush app and followed the steps to sync the module to the Bluetooth on our phones, and it connected seamlessly. The SensorPush will also connect via Wi-Fi, but that requires a separate gateway (not included) that we didn’t have.
We could see the indoor temperature and humidity data on our smart devices. The SensorPush recorded temperatures and humidity levels that were consistent with the other indoor thermometers we tested simultaneously, so we judged it to be accurate. One of the nicest things was the ability to look at the temperature and humidity records in a chart format. That allowed us to see how the levels changed over hours and days.
This is a tiny module, measuring just over 1.5 inches square and only 0.65 inches thick, so it can easily fit in a humidor, wine cabinet, or anywhere you want to monitor the immediate environment.
Get the SensorPush indoor thermometer at Amazon, NorthWoods Humidors, or SensorPush.
In situations where changes in air temperature and humidity can affect indoor plants, such as those in a greenhouse, it’s wise to check the current data and reference it over the past 24 hours. We found the ThermoPro TP55 does that quite well.
The thermometer/hygrometer comes pre-calibrated, so it worked right out of the box. We put it alongside the other modules we tested, and it was within 0.1 degrees of the most consistent temperature and humidity levels. We rated it as highly accurate.
In addition to registering the current temperature and moisture levels, the ThermoPro TP55 also tracks historical data. This makes it well suited for growers who want to know how low the temperature dipped overnight or how high the humidity level rose before the greenhouse fan kicked on.
Yet this ThermoPro TP55 isn’t limited to greenhouse use—we attached it to a file cabinet in our home office to monitor the comfort levels. We were able to select from Fahrenheit or Celsius temperatures, and the display screen indicates the humidity range with Dry, Comfort, or Wet settings. An especially nice feature is the backlight that illuminates the display for viewing in dim situations.
Get the ThermoPro TP55 digital thermometer at Amazon, Target, or ThermoPro.
Why have separate modules when you can see the temperature at a glance just by looking at the clock? In our opinion, that convenience is the primary benefit of the Sharp Atomic Clock. This thermometer offers only temperature, but it detects indoor and outdoor temperatures via an outdoor temperature module that we hung on a tree near the house. We liked the concept, though it took us a good 20 minutes to figure out how to sync the outdoor thermometer with the clock.
The Sharp Atomic Clock recorded the indoor temperature about 0.5 degrees Fahrenheit lower than most of the other thermometers we tested, but we felt that was still pretty accurate. When we compared the reading with our home weather station, set up outdoors, the Sharp was merely 0.2 degrees below that reading.
This clock/thermometer is fairly large, measuring 8.75 inches by 7.9 inches, and it’s 0.75 inches thick. The display is easy to see from across the room, and the unit shows the date and temperature. However, a backlit display for seeing the module at night is lacking.
Get the Sharp indoor thermometer clock on Amazon.
The Govee wireless thermometer hygrometer alerts you to the climate conditions your fur baby is experiencing in real time and by collecting indoor temperature and humidity data for monitoring fluctuations.
First, we installed the Govee Home app, which walked us through the rest of the setup (a Wi-Fi network is required). The app allowed us to see temperature changes over hours, days, and months so we could analyze the temperature and humidity cycles and tendencies.
The module can be affixed to a wall via a peel-off sticker on the back, but unfortunately its small plastic stand proved to be virtually worthless: Even a tiny bump will send the Govee rolling. We recommend affixing the module to a wall in an out-of-the-way spot where it can safely record the data rather than just placing it on a table in the same room where the pet stays. Also, this is not a weatherproof module so it’s not suitable for use in an outdoor doghouse where it might be exposed to rain or snow.
The app worked fairly well; though it didn’t allow us to select between Celsius and Fahrenheit, a small button on the front of the module let us do that. The temperature and humidity readings were in line with most of the other thermometers we tested, so we judged the Govee as highly accurate on both accounts.
Get the Govee indoor thermometer on Amazon.
Those wanting to monitor temperature and humidity levels in more than one area of the home need look no further than Govee’s mini thermometers. Govee’s mini-modules do that job efficiently, and they’re small enough to be placed virtually anywhere without being obtrusive. Each of the three sensors comes with its own lanyard for hanging on a nail, screw, or hook.
We’d already downloaded the Govee Home app, and it quickly synced with the mini-monitors. We were able to name each of the three modules so we could differentiate them from one another in the app. We were able to configure the modules to send alerts at predetermined temperature and moisture levels.
Interestingly, when we placed them side by side and tested for accuracy, each Govee module recorded the exact same temperature and humidity. No inconsistencies whatsoever, which we considered pretty impressive. In addition, the system is expandable, allowing users to connect up to 10 sensors.
The only downside was that we couldn’t monitor the data remotely; since these Govee modules are only Bluetooth capable. They were accurate when located within about 75 feet of our smartphones. This is par for the course for Bluetooth devices, but be aware that you won’t be able to read them when you’re away from home, as you could with WiFi-capable devices. Still, we felt they were among the most accurate, and the ability to monitor several rooms was a winner in our book.
Get the Govee indoor thermometer 3 pack at Amazon, Govee, or Newegg.
Unlike the other indoor thermometers we tested, the LaCrosse Technology Thermometer can be plugged into an electrical outlet as well as run on battery power. This is a great option for folks (like us!) who always seem to be scrambling to find fresh batteries.
We liked the color-coded display on the LaCrosse thermometer—it made it simple to differentiate between the indoor and the outdoor temperatures at a glance. Plus, this unit comes with a backlight that let us easily see the display even in the dark. Of course, if the unit is kept on a nightstand, users must remember the lower right location of the light button and feel for it to see the display at night. The display also shows the date and time, making it well suited for a nightstand clock/thermometer combo.
We rated the LaCrosse as relatively accurate, but when we made the side-by-side temperature comparisons, it was fully 1 degree below the majority of the other thermometers, and its outdoor module registered 0.5 degrees above the temperature detected by our weather station. It’s still plenty accurate for those who want to know the general temperature indoors and out. We found that the outdoor module must be within 50 feet of the base unit to register the temperature, but it will read through walls.
Get the LaCrosse indoor thermometer at Amazon, Lowe’s, or Kohl’s.
Basic and straightforward, the Taylor Indoor Thermometer isn’t wireless; it simply offers indoor temperature and humidity levels. But the design of its colorful comfort display is a great feature: The top half of the screen displays a digital dial with an indicator that ranges from Dry to Comfort to Wet to show how comfortable the combination of temperature and humidity feels in the home.
We liked this feature because we didn’t have to consider what the numbers meant—the dial told us when it was a bit humid. We felt this was a handy function for those who wanted to see the comfort level at a glance. Young children could also probably understand the significance of the dial.
In addition, the Taylor indoor thermometer allowed us to set the time and choose between Fahrenheit and Celsius readings. A slight downside is that the display doesn’t have a backlit option, so it needs to be placed in a bright location.
Get the Taylor indoor thermometer at Amazon, Ace Hardware, or Office Depot.
Why squint at a tiny screen that’s difficult to read and limits the amount of displayable data? With its ample 4-inch screen, the Vivosun can pack in quite a bit of information. In addition to the current temperature and humidity, it also displays highs and lows for both readings (over 24 hours), and a comfort meter shows whether the humidity is too high, too low, or just right.
Our favorite function on the Vivosun thermometer was its touch screen, which let us turn the backlight on and off or toggle between Celsius and Fahrenheit. The light-up feature makes this pick among the best options for low-light situations. The only slight downside we noticed was that the humidity level read a full degree on the low side compared with the other units tested. The temperature, however, was spot-on.
Get the Vivosun indoor thermometer on Amazon, L&B Mall, or Newegg.
Accuracy is crucial when it comes to an indoor thermometer, but other features are also important, including size and connectivity. Here’s what matters in an indoor thermometer.
Most indoor thermometers can read a broad temperature range, making them suitable for monitoring such extreme indoor environments as a refrigerator or freezer. Some indoor thermometers are capable of reading temperatures as low as -50 degrees Fahrenheit and as high as 145 degrees Fahrenheit. These thermometers are also able to take accurate readings. Although most thermometers have a margin of error of a degree or two, the most accurate models are to within half a degree.
Many indoor thermometers also function as hygrometers that can measure the percentage of moisture in the air between humidity ranges of 0 percent and 99 percent, within a margin of error of +/- 2 percentage points.
Some thermometers come with an additional module designed to be located outdoors. These indoor/outdoor models display both the temperature inside the room, plus the temperature outside. The outside module is typically effective only when placed within a specified distance of the base unit, but this distance varies from thermometer to thermometer and can depend on wall thickness as well. A distance of 50 to 75 feet is about the maximum allowable distance to get an accurate outdoor reading.
Indoor thermometers are powered by either a CR 2032 coin battery or one or two AAA batteries. A CR 2032 battery has a capacity of 235 mAh (milliampere hours), while a AAA battery has a 1,000 mAh battery capacity. Although this means that one can generally expect to get a longer battery life out of an indoor thermometer powered by one or two AAA batteries, battery life is also dependent upon the size of the digital display and whether it is backlit. A small indoor thermometer with no backlight that’s powered by a coin battery may have a similar battery life as a larger model with a backlight that takes a AAA battery.
Indoor thermometers vary in size, from small sensors no more than 2 inches tall and 2 inches wide with no display screen to larger units with screens that vary from 2 inches to 4 inches in size. Though it may be easier to read a larger indoor thermometer’s display, a bigger model will take up more space, making them unsuitable for some applications.
Some indoor thermometers consist of a small sensor with no display; instead, data is sent to a compatible app on a smartphone. These compact indoor thermometers are ideal for monitoring the humidity or temperature in close quarters, such as a small humidor or a pet enclosure.
Some indoor thermometers are capable of connecting to a smartphone via Bluetooth, allowing the user to monitor environmental conditions remotely. Quality indoor thermometers can also store months and even years’ worth of data via a cloud storage service, which is useful for those who need to monitor the environmental conditions in a greenhouse, wine cellar, or humidor. The use of Bluetooth gives these thermometers a range of a few hundred feet. Some can even be paired with a compatible smart-home hub, allowing them to send alerts and data to a smart device in virtually any location.
In addition to providing temperature data, most indoor thermometers also act as a humidity monitor. Some indoor thermometers can record high and low temperature and humidity readings over an extended period.
Most indoor thermometers come with multiple mounting options, including a stand that allows them to sit on a flat service, a hole for hanging on a wall, and a magnet that allows them to stick to a metal surface, such as a basement pipe or kitchen appliance.
If you’re wondering how accurate an indoor thermometer and humidity gauge is or whether you can place your indoor thermometer outdoors, read on for answers to these and other questions about these devices.
Most indoor and outdoor thermometers function similarly when measuring indoor and outdoor temperature. The most significant difference between the two is the ability to endure weather conditions. Indoor thermometers are not designed to withstand rain, snow, and UV rays, whereas an outdoor thermometer has waterproof and ruggedly constructed housing to endure the elements.
Most digital indoor thermometers are very accurate within a margin of error that is within a degree. The most accurate models have a margin of error of just plus or minus 0.5 degrees.
Many indoor thermometers are not compatible with Amazon Alexa, Google, or other digital assistants out of the box because they connect using Bluetooth. However, some indoor thermometers can connect to a home Wi-Fi network and then sync with Alexa or Google Home. Though we recommend one Wi-Fi model, the Govee Wi-Fi Thermometer, it does not sync with digital assistants.
To get the best readings, put an indoor thermometer about 5 to 6 feet above the ground in a location away from direct sunlight, a stove, a heater, or a heating vent.
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