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It’s winter, which means it’s humidifier season. If you struggle with dry skin, allergies, or have a cold, you might be running yours. Over 20 million were sold in the US in 2019, and they’ve only grown more popular in the last few years, as consumers have become more concerned with the air quality of their homes. 

There’s no shortage of models on the market, but you might be hard-pressed to find a humidifier you love rather than merely tolerate. Those looking for advice online often ask: How do I find a humidifier that works well for my space, but also one that isn’t a complete pain to clean?

The short answer is that there isn’t a magical way to avoid humidifier maintenance. A humidifier is filled with water, and where there’s moisture, mold and bacteria will grow.

The worst mishap that might occur with a robot vacuum is that it runs over an unpleasant surprise your dog left on the floor. With humidifiers, you could be breathing in particulate matter that causes more serious health issues than the device purports to solve. 

Older humidifiers often looked terrifying and were used mostly in hospitals to help people with respiratory conditions. In the latter half of the 20th century, they started being advertised as consumer products. Today there are three types available: ultrasonic, which uses vibrations to turn water into mist; evaporative, which uses a fan to help evaporate water into the air; and the warm mist humidifier, which boils water to produce steam. 

“Most of the stuff that’s on the market tends to be ultrasonic at this point,” says Allen St. John, senior tech editor at Consumer Reports. They’re generally easier and quieter to use.

But every humidifier comes with trade-offs. Ultrasonics emit a lot more particulate matter than evaporatives do (more on that later); evaporatives might be louder, and also require you to buy and replace a filter or wick. With warm mist models, you run the risk of scalding yourself (or a pet or child in the house) if you knock it over. And none are particularly easy to maintain: The Environmental Protection Agency advises cleaning a humidifier every three days.

It’s also important to be careful about what cleaning agents you use and how well you rinse the humidifier before turning it on again — you don’t want to inhale any harmful chemicals. In South Korea, humidifier disinfectants that were widely available until 2011 have been linked to the deaths of over 1,800 people.

“It’s easy to get to the point of, ‘I didn’t really clean it, now this thing looks like a science experiment,’” St. John says.

Given how frustrating they can be to own, people often have impassioned opinions on humidifiers.

A few years ago, there was a considerable amount of reader complaint and discourse around the fact that Wirecutter had named the Honeywell HCM-350 humidifier their top pick for several years. The humidifier guide is “easily one of the most volatile reader comment sections,” says Thom Dunn, who writes Wirecutter’s humidifier guide. The top pick now is the Levoit LV600S. Unsurprisingly, several recent comments disagree with the choice. (McSweeney’s lampooned how even the most recommended humidifier will inevitably disappoint.)

There’s another reason humidifiers cause so much consumer disdain: Many of them are, frankly, ugly. The good news is that the age of more attractive design may be upon us. 

More brands are giving the humidifier the millennial-sleek update thanks to a broader “air care” wellness trend — which includes products like candles, diffusers, and air purifiers too. 

“It does go along with a certain influencer wellness aesthetic,” Dunn says.

But the real issue with humidifiers isn’t just their clunky aesthetic or their required upkeep. It’s that they can be a serious health hazard.

“Ultrasonic humidifiers … create a lot of small particulate matter,” says Jonathan Jarry, a science communicator at McGill University's Office for Science and Society. They “aerosolize minerals that are present in the water,” which means the purity of the water you’re using in a humidifier can drastically impact your home’s air quality.

University of Alberta scientists published research showing that ultrasonic humidifiers using both filtered and unfiltered tap water released high concentrations of particulate matter seen “during extreme air pollution events in major metropolises.” A 2023 paper published in Science of the Total Environment found that safe-to-drink tap water used in ultrasonic humidifiers could spew out dangerous levels of metals that are more harmful inhaled than when ingested, such as manganese. 

In short, using anything but distilled water in your humidifier means you could be inhaling a lot of stuff you probably don’t want in your lungs. (Evaporative humidifiers can also emit particulate matter, but to a lesser extent.)

The EPA recommends using only distilled water in humidifiers, but acquiring large enough quantities of it cheaply is easier said than done. To be clear, boiling water is not the same as distilling it, and bottled drinking water isn’t usually distilled either. Distillation requires boiling water “into a vapor and leaving behind any impurities, and then taking that vapor and recondensing it back into a liquid,” Jarry says.

According to a recent Centers for Disease Control and Prevention report, many Americans have misperceptions about the purity of tap water. A third of respondents to a survey thought that tap water was sterile, and a quarter said they used it for humidifiers. 

The big question mark around the safety of these popular products adds yet another hurdle for consumers looking for a humidifier that won’t make them miserable. If you’re not prepared for the commitment of bringing a humidifier into your home, the healthiest option — for both your lungs and your sanity — might just be to opt out.

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The horrifying rape case that reverberated around the world: On Thursday, Dominique Pelicot was given the maximum sentence of 20 years for drugging and raping his wife, Gisèle Pelicot, and inviting dozens of others to sexually assault her as well. The case has prompted a reckoning in France, but Gisèle Pelicot’s brave public battle has also shined a light on marital rape and the impact of rape culture around the world.  

The fake narrative about plant-based “meats”: The world is still trying to sort out the effects of so-called ultra-processed foods on our health, and that’s raised questions about where plant-based food, and especially vegan meats such as Impossible meat and Beyond burgers, fit in. But a study this year has led to a false impression that plant-based meats are disease-promoting. Here’s why you should be skeptical. 

What doctors wish you knew about the health care system: After the killing of UnitedHealthcare CEO Brian Thompson raised a broader conversation about the rotted foundations of US health care, doctors are speaking out about their own dissatisfaction with the system and the ways it is burning out health care workers when we need them most. 

A surprising way to instill a love of learning in children: A wave of podcasts is quietly reinventing kids’ entertainment, drawing Gen Alpha in with immersive storytelling at a time when fewer children are reading for pleasure and concerns about young people’s media diets are rising. They could be a new gateway to a love of learning and improving media literacy.

Covering for Biden: Concerns over the president’s diminished capacity ultimately led to him dropping out of the 2024 race. A new investigation paints a troubling portrait of how the White House functioned during his term. [Wall Street Journal]

“Crunchy” goes conservative: As the MAHA movement is proving, certain health and environmental concerns once coded as lefty are now being taken up by the right. [New York Times]

When private pain is public: What happens when your divorce exists “in the shadow of my husband’s new relationship with a celebrity?” A Wicked star’s ex-wife writes about the personal and professional effects. [The Cut]

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President-elect Donald Trump’s lawsuit against Disney, the parent company of ABC News, was settled for $15 million, but a wave of new lawsuits have followed, including a curious filing this week against the Des Moines Register for a poll showing Kamala Harris would win the November election; Trump has called the poll “election interference.” 

These kinds of cases are commonly called strategic litigation against public participation (or SLAPP) suits, and, as one expert told Vox’s Ellen Ioanes, “What really marks a SLAPP suit, aside from it being legally baseless, is that the intent is not so much to win, but to send a message to bully and punish critics.” Read more about this legal strategy and why it could have a chilling effect on news coverage here. 

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Today’s edition was produced and edited by staff editor Melinda Fakuade, with contributions from senior editor Lavanya Ramanathan. We'll see you tomorrow!

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