As a side result of using an ultrasonic air humidifier, this white dust thing can be seen on house furniture during its activity. I googled about it but I only found a few articles, saying that it is safe for human body but I found nothing about house devices. Does it have any bad effect on my LED TV? I use a homemade cover for it but, I'm still kind of worried.

  • 4
    \$\begingroup\$ I would not trust the web regarding human safety. Worry about yourself before you worry about your possessions. Use distilled water in the humidifier (buy at local drug store) .... as far as safety for electronic devices, probably not safe if water contains dissolved salts. No idea about other minerals, but i guess that any iron content could cause degradation in electronics performance. \$\endgroup\$
    – jsotola
    Jan 1, 2018 at 20:05
  • 1
    \$\begingroup\$ If you're covering your TV, I'd be concerned about it overheating due to lack of airflow. \$\endgroup\$ Jan 1, 2018 at 22:02
  • 1
    \$\begingroup\$ @jwygralak67 Hi there, I'm not using cover when TV is on. Usually, I try not to use humidifier when the TV is on. \$\endgroup\$
    – Vynylyn
    Jan 2, 2018 at 6:05

3 Answers 3


White dust:

White dust is usually caused by mineral content in the water that goes into a humidifier. When the mist lands on furniture or other surfaces and dries, it can sometimes leave behind the dried mineral deposits, or “white dust”.

The dust is a salt (ionic compound). The dust should be safe when dry, but as soon as it absorbs moisture it will become electrically conductive.

I would be more concerned about the liquid water that appears before the dust.

You could use distilled water as suggested by @jsotola to avoid the issue altogether.

I was wondering for myself a moment why "normal humidity" doesn't cause the white dust, but only the humidifiers do:

Ultrasonic humidifiers work by splashing water everywhere, the same thing you can do with your arms in water, the only difference being the size of the droplets.

So you should definitively use distilled water as the humidity from an ultrasonic humidifier is basically like splashing water on electrical appliances.

Tiny droplets of distilled water shouldn't be much different from normal humidity which generally isn't an issue.

  • \$\begingroup\$ @Oslar Skog Hi there, You wrote: "I would be more concerned about the liquid water that appears before the dust." Is it wet when it's being absorbed to the surface or is it just dry dust that is absorbed to surfaces due to its ionized nature? I'm asking this because there's a considerable distance between humidifier device and TV that makes me think that it must become dried out before reaching TV surface or am I wrong?! \$\endgroup\$
    – Vynylyn
    Jan 2, 2018 at 6:11
  • \$\begingroup\$ The article suggests that the water dries up and leaves the white dust behind, so I assume it may be humid when adsorbed to surfaces. But I don't know. \$\endgroup\$
    – Oskar Skog
    Jan 2, 2018 at 8:33
  • 1
    \$\begingroup\$ Tiny drops of water are still that, drops of liquid water. Humidity in the air is different, it is not liquid. The tiny drops will conduct and depending on the circuit damage it \$\endgroup\$
    – PlasmaHH
    Jan 2, 2018 at 9:47

Ultrasonic humidifiers have a way of vaporizing that causes the lime sediment in water to evaporate and condense on any nearby surface unlike steamer and spin drum (hot & cold types) .

A demineralization water filter can work.

Lime can be harmful , long term , to lead solder joints in copper plumbing, so water softening is recommended to remove the minerals. Boiling water will also leave a white sediment in kettles, coffee boilers and cooking pots, according to how “hard” the water is.

Lime is not conductive or very salty as far as ionic levels are concerned so it will be harmless when dry.

  • \$\begingroup\$ Evaporating lime would be impressive. In reality, dust is created when an impure water droplet evaporates, leaving a small speckle of dust behind. \$\endgroup\$
    – MSalters
    Jan 9, 2018 at 15:01
  • \$\begingroup\$ It is the corrosive stuff on copper pipe solder joints caused by hard water and prevented by a water softener.. Perhaps it depends on location but I was thinking of calcite from limestone \$\endgroup\$ Jan 9, 2018 at 15:36

The most practical and economical solution I have found to the problem of minerals depositing on my electronics while I run the ultrasonic humidifier was to buy a small, very affordable water distiller. It can produce a gallon of distilled water every 4 hours (which in my case is enough to run the humidifier for a little over a full day), while using just under 3kW of power (which cost around 20 cents where I live). This avoids buying and tossing plastic jugs of distilled water, which cost about 2 bucks a gallon.

The small, positive side effect of running the distiller is that during operation it releases heat, so I run it in the morning, after I leave for work, while the noise doesn't disturb anyone in the family, and sort of heats up the room a little in the meantime. It shuts down automatically when it's done. When I get home in the evening, I have a gallon of distilled water, which I mix ~50/50 with tap water. With only half of the minerals in the humidifier as I would with 100% tap water, the built-in de-mineralizing cartridge/filter does a great job at completely eliminating the white dust.

  • \$\begingroup\$ Welcome to Stack Exchange Electrical Engineering! This is useful information, but it doesn't answer the question of whether the 'white dust' is bad for electronics. (note: I'm not the anonymous coward who downvoted you without any explanation) \$\endgroup\$ Jan 28, 2020 at 10:00
  • \$\begingroup\$ @BruceAbbott It does not answer the question but does provide an alternative so that the question need not arise. Upvoted. Personally I would be bothered about breathing stuff dissolved in tap water, irrespective of its effects on electronics \$\endgroup\$ Jan 28, 2020 at 11:35
  • 1
    \$\begingroup\$ I have to recognize that the only reasons I wrote my reply as an answer and not a comment, is that 1) there's no answer-fits-all, as dust-conductivitiy depends on the composition of the minerals dissolved in each household's water (usually calcium and magnesium, but there's a lot more to it), and 2) I didn't have enough "credit" to write comments. \$\endgroup\$
    – FrK
    Jan 29, 2020 at 10:43

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.