Can turning up my home’s thermostat kill pathogens?

3 minute read


This is a common question with an even simpler question beneath it: does heat kill pathogens? On its face, raising the temperature in your home seems like a simple solution. After all, our bodies run fevers when fighting infection, and we advise people with the flu to “sweat it out” in the gym or shower. So doesn’t it stand to reason that heat kills germs at home?

Unfortunately, the answer is a pretty straightforward “no.” Sure, heat above a certain temperature does absolutely kill pathogens. But unless you’re prepared to crank your heat up to a scorching 140 degrees F, you’re out of luck.

In fact, temperatures between 40 and 140 are in what experts call the “danger zone,” which can actually SPEED UP microorganism reproduction. The World Health Organization warns that heat any less than 212 degrees (water’s boiling point) isn’t enough to fully kill off harmful pathogens.

Unless you’re prepared to crank your heat up to a scorching 140 degrees F, you’re out of luck.

[Also, in case you’re wondering: no, sub-zero temperatures don’t kill pathogens either. Some of the more sensitive germs might be affected, but most microorganisms (especially viruses) will just slow their internal processes to conserve energy until they heat back up. That’s why eating frozen food with E. coli will still get you sick.]

If you’re looking for proven pathogen-killing power, however, we suggest choosing a UV-C air sanitizer for your home or business instead. Rather than using heat, UV-C sanitizers use shortwave light to disrupt pathogen DNA. Admittedly, it’s not quite as dramatic as trying to roast germs alive, but at least it doesn’t require keeping your home at infernal temperatures to be effective.

Humans are orders of magnitude more sensitive to temperature than microorganisms are. So if you’re thinking that a few degrees will help you win the war against household pathogens, you might want to think again. They’ll keep on doing what they’re doing, without even breaking a sweat.

 Related Questions

Wait, don’t people get sick more often in cold weather?
Not as much as you might think. Seasonal illnesses like influenza have conditioned us to believe that sickness goes up as the temperature goes down. But flu season actually has a lot less to do with the temperature, and a lot more due to lower air humidity and from people being cooped up inside in close proximity. Think about it: if people get sick more in colder temperatures, then why are there so many illnesses that thrive in tropical climates?

So then why do we wash our hands with warm water?
Contrary to popular wisdom, washing your hands isn’t really about killing germs — it’s about removing them. Washing with soap actually makes the water “wetter,” which helps the water slough off any latent pathogens more easily. Using warmer water on your hands can loosen debris in the same way that washing your dishes in warm water does. The heat of the water, however, doesn’t matter much (and, in fact, there’s evidence that water temperature has no impact on the effectiveness).

Doesn’t the air circulate through my furnace? Isn’t than hot enough?
Nope. Your furnace definitely gets hot, but not hot enough to get out of the “danger zone” for pathogens. Even HVAC companies recommend adding a UV light purifier to the system if you’re looking to sanitize the air via your home’s HVAC system.

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