Is an Oral or Infrared Thermometer Accurate?

From checking for a child’s fever to checking if food is cooked thoroughly, to troubleshooting a heating, ventilation and air conditioning (HVAC) system, thermometers are everywhere, and they’re invaluable for measuring temperatures. Whether a parent or a pro, it’s always important to have a thermometer that’s accurate and quick to respond.

There are many, many kinds of thermometers that can be classified by how they are used and what technology they use. For this article, we’re going to focus on oral thermometers and non-contact infrared thermometers. Knowing what the options are can help you pick the right instrument for the job. Here’s what you need to know about oral and infrared thermometers.

Open wide: Pros and Cons of Oral thermometers

Oral thermometers, or thermometers that are placed in the mouth, fall into the contact thermometer category. For consumers, health clinicians, and parents, these are typically the most common kind. Temperatures taken from the mouth are usually accurate for children older than 3 and adults. It’s important to keep the mouth closed while the thermometer is in place.

Oral thermometers may take an accurate temperature usually in less than one minute. Compared to older mercury thermometers, that’s quick. But it may be considered slow next to infrared thermometers which usually work in seconds.

Some downsides of oral thermometers include a waiting period of 15 minutes after eating or drinking. You may not realize it, but food/drink temperatures can affect the thermometer’s readings. And for anyone who is breathing through their mouth, presumably because of nasal congestion, they might find it hard to keep their mouth closed for the period of time needed to take an oral temperature accurately. Finally, oral thermometers can be the same kind of thermometer used for rectal temperatures—important for children under three. So, if both types of readings are done, it will be necessary to have two labeled thermometers for hygiene reasons.

Infrared thermometers for clinical care

Infrared thermometers use an infrared heat sensor to detect temperature of a surface remotely—without having any contact. For clinical purposes, they are useful for screening large numbers of people, such as groups waiting to be admitted to an event or facility, like an airport, travel hub, or school. They are quick, providing a reading in as quick as half a second. Patients find they are easily tolerable since there is no discomfort or contact. They can also be used on children of all ages, as well as adults.

It’s important to remember that, in a clinical context, a high quality infrared thermometer is usually accurate enough to identify a temperature in the range of normal body temperatures (between 97° F (36.1° C) and 99° F (37.2° C) or more) but users have to take into account direct sunlight on a person’s face, cold ambient temperatures, or a sweaty forehead. And, users must remember to take measurements within the meter’s indicated distance.

Beyond health: Putting infrared thermometers on the job

Outside of clinical care, infrared or IR thermometers are also used in a very wide range of jobs to get accurate readings of normal or abnormal operating conditions. The advantages of infrared thermometer in commercial and industrial applications are numerous.

HVAC techs use IR thermometers to measure the surface temperature of a vent to get an indication of air temperature. They may use it to scan coolant line temperatures and other components for in-range operating temperatures.

Electrical contractors use IR thermometers to identify whether there may be an abnormally hot circuit on a breaker board, indicating excessive loads or added resistance from pitting or corrosion.

In industrial plant and manufacturing settings, IR thermometers can scan motors, belts, pulleys, switches and cables for atypical temperatures that may suggest something is malfunctioning or nearing failure. By predictively identifying imminent failures, plant maintenance techs can schedule downtime to repair or replace components without the added costs and disruptions from an unexpected failure.

In food processing, grocery/supermarkets and refrigerated supply chains and logistics, IR thermometers are used to accurately check the temperature of frozen and refrigerated foods to ensure they are not at risk of bacteria and spoilage.

Road construction crews monitor asphalt curing with infrared thermometers to determine the status of a paving job and the quality of asphalt being used. As you can see, whenever temperature is a factor, IR thermometers are invaluable.

Coupling added accuracy with added safety at a distance

Being able to quickly scan for accurate temperature readings, IR thermometers allow professionals to take readings at a safe distance. This may be helpful when working near moving machinery or equipment that can get dangerously hot.

Sometimes, important temperatures are needed from equipment that is inaccessible or hard to reach. Having a point-and-shoot way to get readings can mean added safety and faster work, eliminating the need for ladders, or scheduling downtime to get closer to hazardous equipment.

Remember, when asking is an oral or infrared thermometer more accurate, the answer may be, it depends. Oral thermometers are accurate for patient care. For jobs in and outside of direct clinical care, infrared thermometers bring numerous advantages and safety benefits that also complement their accurate capabilities.