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Humidifiers - Ultrasonic vs Evaporative Humidifiers

Expect Some Trade-offs Between Ultrasonic and Evaporative Humidifiers


Humidifiers - Ultrasonic vs Evaporative Humidifiers

Honeywell Evaporative Wick Filter Humidifier

Photo © Mifflin
The two main types of portable humidifiers are ultrasonic and evaporative. And while either can be efficient in terms of humidifying a room, they have significant differences in how they produce that moisture and you may have to accept some trade-offs, if you want to get the unit with your preferred characteristics. There are basically three major differences between an ultrasonic and evaporative humidifier: Price, operation noise and how each handles mineral scale deposits (white/grey dust). But first, you need to understand how the two types differ from one another:
Ultrasonic Humidifier - Definition
Evaporative Humidifier - Definition

1. Price Considerations

With two totally different types of humidification systems, there's bound to be some noticeable differences in operation. An evaporative humidifier is cheaper to buy, but most have filters - usually wick style - that must be either washed or changed periodically. So a lower cost up front is followed by more maintenance costs later, not to mention having to locate the correct replacement filters. Replacement filter costs tend to vary depending on size and brand, but most are low cost.

On the other hand, an ultrasonic humidifier does not use filters and generally costs more to buy than an evaporative model. There's no filter to replace, but an ultrasonic humidifier still should be maintained properly to avoid mold and bacteria.

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Learn About Changing a Humidifier Wick Filter
Learn About Humidifier Maintenance

2. Quiet Operation

The most common place for a portable humidifier is in the bedroom; secondary is the main living space, so it's no wonder that the majority of consumers want a humidifier with quiet operation. If humidifier noise is your main concern, an ultrasonic humidifier is your best choice. While there are some with optimum quiet operation, most ultrasonic humidifiers tend to operate quieter than other models. That's because they do not have a fan, as evaporative humidifiers usually do. This keeps noise levels down.

If noise is not a concern but budget is, choose a more affordable evaporative humidifier. You should understand though that even those humidifiers that tout a quiet operation will be noisier when used on anything but low (moisture volume); it's impossible to totally eliminate the operation noise of humidifiers.

3. Annoying Humidifier White Dust

Ultrasonic humidifiers tend to discharge more white/grey dust than evaporative humidifiers. That white/grey dust is actually water mineral deposits, which will be more extreme the harder your water is. Hard water is caused by the presence of mineral deposits in your water source and varies depending on your particular source for drinking water.

The reason an ultrasonic humidifier produces more dust is because it has no filters to trap or contain those mineral deposits and they are returned to the room along with the moisture, only to land on furniture and electronics as dust - basically on anything close to the humidifier.

Remedies to control the humidifier white dust are: Use distilled or reverse osmosis water; a humidifier decalcification filter if there is one available for your humidifier model; or run the humidifier moisture on low to reduce the amount of dust you need to clean. It's impossible to eliminate this white dust - the mineral deposits in the water have to go somewhere. It's a little trade-off when you choose an ultrasonic humidifier. The larger the output of moisture, the more dust to clean. Also keep in mind that there are some compact, especially personal size evaporative humidifiers that have no filters in their design. Because the output is a smaller volume of moisture, mineral scale dust is barely noticeable, if at all.

Which Type is Best for You?

If you loathe humidifier filter change/cleaning or simply want a quieter humidifier - chose an ultrasonic model. You'll pay more up front and be prepared to clean around the humidifier more often.

For budget pricing, choose a evaporative humidifier, but understand that filters do need periodic changing or cleaning to keep them running efficiently. Locate filter replacements before buying a humidifier and always have a spare filter on hand.

Read More About Humidifiers:

Humidifier Facts
Portable vs Console Humidifiers
Humidifier Care and Maintenance Tips
What's the Difference Between a Hygrometer and Humidistat?
What's a Hygrometer and Do You Need One?
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