5 best thermometers of 2021 - INSIDER

FAQs

Which type of thermometer is the most accurate?

Dr. John Vann, a pediatrician in Omaha, told Insider that only a rectal temperature offers a true outpatient reading. "Everything else is an estimate," he said.

"Luckily, the exact number is not usually as important as how the patient looks," he adds. Which is to say, there are other indicators of how severe someone's illness or condition is other than an optimally-accurate temperature reading. There are also reliable methods for checking your temperature even if you don't have access to a thermometer.

No matter if you opt for an infrared thermometer or a strictly ear-based model, it's important to know fever isn't the same for everyone and that it varies by age, gender, and time of day, among other variables. Using a thermometer at various times of the day when you're feeling well gives you an idea of what's normal for you, or your baseline temperature. 

Which is the best thermometer for home use?

Among at-home thermometers, medical research hasn't determined an exact correlation between oral, rectal, ear, armpit, and forehead temperature measurements. But Kaiser Permanente notes that an ear (tympanic) temperature is 0.5 to 1 degree higher than an oral temperature and a forehead (temporal) scanner is usually 0.5 to 1 degree lower than an oral temperature. 

What is the best thermometer to use for COVID?

The best thermometer for COVID is really just one that is accurate and reliable. That means any of the thermometers on our list are great for checking for COVID symptoms. That being said, if you're using the thermometer on more than one person, it's best to use a contactless reader to not cross-contaminate. In that case, we highly recommend the iHealth No-Touch Forehead Thermometer PT3 or the Exergen Temporal Artery Thermometer with Smart Glow, both of which proved to be accurate and reliable in my tests.

Can I use my HSA/FSA funds to buy a thermometer?

If you have an HSA or an FSA account, know that over-the-counter digital thermometers are eligible for reimbursement without a prescription. 

Here's how it works: 

• If you pay with cash or credit card in a store or online, you can request a reimbursement from your HSA/FSA account. Different plans have different requirements on what's needed for reimbursement but usually, a copy of your thermometer receipt will be enough.
• There are HSA and FSA-specific retailers, like the HSA Store and the FSA Store that make shopping for items that qualify for reimbursement really simple. According to both websites, when shoppers use an HSA or FSA card to pay, they typically don't have to submit receipts; purchases on these websites automatically substantiate. It is worth noting, however, that the thermometer options available on these websites are limited and cost more than other retailers. 

What counts as a fever?

Many Americans think anything over 98.6 degrees Fahrenheit is a problem, but what constitutes a fever is actually different person to person.

Rik Heller, a biomedical engineer and thermographic expert, tells Insider, "Age, gender, and even time of day impact normal body temperatures." 

Some children's temperatures especially run higher than others, points out Dr. Jesse Hackell, a practicing pediatrician with New York-based Pomona Pediatrics. Any reading of 100.4 F or higher in a baby younger than 3 months is reason to call the pediatrician. "Another reason to call is if the fever persists for more than 24 hours in children younger than two and more than three days in a child 2 years of age or older," he said.

Meanwhile, older adults tend to have lower baseline temperatures than younger adults; sometimes fevers in the elderly are completely absent.

To figure out what's a fever for you, you want to find your baseline temperature (i.e., what's normal for you) by checking your temperature at various times of the day when you are feeling well. 

At the end of the day, how you or your child is acting and feeling is the best indicator of a fever over the number on a thermometer, multiple of our doctors say.