How to Check Room Temperature with or without a Thermometer

Download Article

The most accurate ways to find ambient temperature, plus the ideal temperature for your home

Co-authored by Dan Hickey

Last Updated: June 11, 2024 References

Download Article

Using Smartphone Sensors & Apps

|

Using Traditional Thermometers

|

Ideal Room Temperatures

|

Video

|

Q&A

|

Tips

ARTICLE

VIDEO

You’ve got your thermostat set to 72 °F (22 °C), but you’re still feeling chilly. Now you’re wondering, “What’s the actual temperature of the room? Is my thermostat accurate?” Thankfully, there are a variety of tools you can use to measure room temperature (and you might have one of them in your pocket right now!). In this article, we’ll show you how to measure room temperature with your smartphone (using its internal thermometer or an external sensor) plus the best way to use 3 kinds of good old-fashioned thermometers. Now let’s see what the temp really is!

Things You Should Know

Check room temperature accurately with a smartphone by connecting to an external sensor or weather station.
Use digital, glass, or bimetallic thermometers by placing them in the center of the room (at least 2 ft (0.61 m) high) and reading them after about 5 minutes.
The recommended room temperature for healthy adults is between 64–75º F (18–24º C).

Method 1

Method 1 of 3:

Using Smartphone Sensors & Apps

Download Article

1
Be wary of the results from thermometer apps for iPhone or Android. Few smartphones have the right equipment to accurately read room temperature—their sensors only monitor the battery temperature and are affected by heat radiating from the phone. This means that thermometer apps can only give rough, often inaccurate estimates of room temperature unless they’re designed with a specific ambient temperature sensor.^{[1]
X
Research source}
- Some popular thermometer apps include Room Temperature Thermometer, HD Thermometer, and Real Thermometer.
- Some phones with external temperature sensors are the Samsung Galaxy S4, Samsung Galaxy Note 3, Motorola Moto X, Huawei Ascend P6, and Xiaomi Mi3.
- The number of phones with accurate sensors has been declining since it’s not a popular or easy to manufacture feature.
2
Get an external temperature sensor or weather station for your phone. For accurate readings, connect your phone to an external thermometer. Look for devices that connect to WiFi or Bluetooth—many can also read humidity, air quality, and more. Then, download the accompanying app to your phone so you can read results and adjust settings from the palm of your hand.^{[2]
X
Research source}
- WiFi models are more expensive than Bluetooth ones, which can only work if your phone is within a certain distance of the sensor device.
- External sensors and weather stations can also be connected to an Amazon Alexa or Google Home system if you have one.
Advertisement
Wait for the app to finish downloading, then tap on it to open it. Depending on the product, you may have to create an account to sync the device with the app. Make sure you’re connected to the same WiFi network as your external device if it uses WiFi. If it uses Bluetooth, connect your devices to enable use.^{[3]
X
Research source}
4
Go to the app’s home screen or select the room temperature reading. The app’s display will look different depending on which device you’re using, but the temperature reading will be easy to find. Make sure you’re looking at the room or ambient temperature and not the weather forecast.^{[4]
X
Research source}
- Adjust your settings to your preferred temperature system (Fahrenheit or Celsius), or convert the reading yourself if you feel like doing some math!

Method 2

Method 2 of 3:

Using Traditional Thermometers

Download Article

1
Try a digital thermometer for the most accurate temperature reading. Electronic and digital thermometers are pricier than other types, but they provide the fastest and most precise temperature readings. They react to air temperature changes very quickly, so you’ll always be confident in the current temperature.^{[5]
X
Research source}
- Some digital models store temperature data over a certain period of time so you can evaluate changes in the room’s temperature.
2
Use a classic glass thermometer for approximate temperature readings. Opt for one that doesn’t contain mercury, since it’s highly toxic and dangerous if the thermometer ever breaks.^{[6]
X
Trustworthy Source

United States Environmental Protection Agency
Independent U.S. government agency responsible for promoting safe environmental practices

Go to source} These thermometers use a glass tube (a capillary) with a liquid inside. As the temperature rises, the liquid expands and moves farther up the tube.^{[7]
X
Research source}
- These thermometers are slower to adjust to temperature changes than digital ones and can only provide an approximation of the ambient temperature.
- Glass thermometers are also called bulb or liquid-in-glass thermometers.
3
Try a bimetallic thermometer for a decorative or easy-to-read option. These thermometers have a display dial with a pointer (similar to a clockface) that moves to show you the temperature. They have a metal strip that expands and bends as the room temperature rises, which moves the pointer on the dial.^{[8]
X
Research source}
- The large pointer on the dial makes it easy to see the temperature from far away. However, bimetallic thermometers aren’t as accurate as digital ones.
- Bimetallic thermometers can look relatively plain or be made to look like compasses, clocks, sundials, or feature other designs.
4
Put the thermometer in the center of the room, at least 2 ft (0.61 m) high. This is the ideal spot to get an accurate reading since it’s sitting height for most people and away from the heat or cold of floors and walls. Make sure there are no drafts or heat sources near the thermometer, since these will throw off the reading.
- Try setting the thermometer on a table or stool to keep it off the (usually cold) floor.
- Keep the thermometer out of direct sunlight, which will produce a warmer reading.
5
Wait 5 minutes for the thermometer to adjust to the room temperature. Back away from the thermometer so your body heat doesn’t influence the reading. Most thermometers, especially glass or bimetallic ones, will take at least several minutes to adjust to changing temperatures.^{[9]
X
Research source}
- Digital thermometers work fast and may show results in about 1-2 minutes.
6
Read the thermometer without holding or touching it. Leave the thermometer on the table so the heat from your hands doesn’t change the reading.^{[10]
X
Research source} For most people, a comfortable room temperature is somewhere between 18–24º C (64–75º F).^{[11]
X
Research source}
- Digital thermometers: Read the numbers on the digital display to see the temperature. This reading is the most accurate.
- Glass thermometers: Read the number or tick mark closest to the top of the liquid in the tube. Keep your eyes level with the top of the liquid for accuracy.
- Bimetallic thermometers: Look at the number or tick mark that the pointer is pointing to, similar to how you would read an analog clock.

Method 3

Method 3 of 3:

Ideal Room Temperatures

Download Article

1
Keep most rooms in your home between 64–75º F (18–24º C). The World Health Organization (WHO) and other health groups recommend a minimum room temperature of about 64º F (18º C) for healthy adults who are appropriately dressed for the season. This range is ideal for rooms like living rooms, where people are largely sitting still while visiting or watching TV.^{[12]
X
Research source}
- For the elderly, very young, or the sick, raise the minimum temperature to about 68º F (20º C).
Cooler temperatures are best for sleep since a decrease in temperature triggers your body to start feeling tired. Sleep psychologists suggest thinking of your bedroom as a “cave” to get great sleep—keep it cool, dark, and quiet.^{[13]
X
Trustworthy Source

Cleveland Clinic
Educational website from one of the world's leading hospitals

Go to source}
This temperature keeps you comfortable when you get out of the shower or bath (stepping out into drastically colder temperatures can have negative impacts on your health). It’s also just a pleasant temperature whether you’re using the bathroom in the middle of the night or at any point during the day.^{[14]
X
Research source}
4
Save money by keeping your home around 78 °F (26 °C) in the summer. The U.S. Department of Energy suggests keeping your thermostat as high as comfortably possible in warm weather during waking hours. Lower your home’s temperature at night when you go to sleep for comfort, and set your thermostat slightly higher when you’re away for hours at a time to save energy.^{[15]
X
Research source}
- The smaller the difference between the indoor and outdoor temperatures, the lower your air conditioning bill will be.
5
Maintain a daytime temperature of about 68 °F (20 °C) in winter. Save energy and money in cold months by keeping your home slightly cooler. When you’re asleep or away for long periods of time, lower your thermostat a few degrees.^{[16]
X
Trustworthy Source

U.S. Department of Energy
Official site for the U.S. Department of Energy, which provides resources related to energy safety, conservation, and efficiency

Go to source}
- If you’re going away for days or weeks at a time in winter, keep your thermostat at a minimum of 50 °F (10 °C) to prevent your pipes from freezing and bursting.

Community Q&A

Search

Add New Question

Question

How to tell Fahrenheit?

wikiHow Staff Editor
Staff Answer
This answer was written by one of our trained team of researchers who validated it for accuracy and comprehensiveness.

wikiHow Staff Editor

Staff Answer

To convert temperatures in degrees Celsius to Fahrenheit, multiply by 1.8 (or 9/5) and add 32. However, most physical thermometers will show readings in both C and F, and digital thermometers or phone apps can toggle between the two in settings.

Thanks! We're glad this was helpful.
Thank you for your feedback.
If wikiHow has helped you, please consider a small contribution to support us in helping more readers like you. We’re committed to providing the world with free how-to resources, and even $1 helps us in our mission. Support wikiHow
Yes No

Not Helpful 6 Helpful 1
Question

If we only have contact thermometer, is it still okay to measure room temp by placing a glass of water and let it sit at room temp and then measure the temp of water?

wikiHow Staff Editor
Staff Answer
This answer was written by one of our trained team of researchers who validated it for accuracy and comprehensiveness.

wikiHow Staff Editor

Staff Answer

Yes, but the water will have to sit for a very long time. It can take as long as 24 hours for water to adjust perfectly to room temperature (the smaller the amount of water, the faster it will acclimate).

Thanks! We're glad this was helpful.
Thank you for your feedback.
If wikiHow has helped you, please consider a small contribution to support us in helping more readers like you. We’re committed to providing the world with free how-to resources, and even $1 helps us in our mission. Support wikiHow
Yes No

Not Helpful 3 Helpful 6
Question

Can you use an iPhone 6 phone to measure room temperature?

wikiHow Staff Editor
Staff Answer
This answer was written by one of our trained team of researchers who validated it for accuracy and comprehensiveness.

wikiHow Staff Editor

Staff Answer

Not very accurately, unless you connect it to an external temperature sensor or weather station. Most smartphones don't have the right hardware to take room temperature.

Thanks! We're glad this was helpful.
Thank you for your feedback.
If wikiHow has helped you, please consider a small contribution to support us in helping more readers like you. We’re committed to providing the world with free how-to resources, and even $1 helps us in our mission. Support wikiHow
Yes No

Not Helpful 3 Helpful 7

See more answers

Ask a Question

200 characters left

Include your email address to get a message when this question is answered.

Submit

Video

Tips

If the temperature feels “just right” in a room, it’s probably somewhere between 72–76° F (22–24° C). This is the range where most people can radiate their body heat and keep their internal temperature at 98.6 °F (37.0 °C).^{[17]
X
Research source}

Thanks
Helpful 0 Not Helpful 1