Humidifiers and Dehumidifiers: How Much Energy Do They Consume?

How much energy do humidifiers and dehumidifiers consume? We took a look. Read about what energy consumption and picking the right dehumidifier.

Humidifiers and Dehumidifiers: Energy Saving and Consumption

Everyone wants to be healthy. Every day we make decisions that affect our health, both short and long-term. The decision to buy a humidifier or a dehumidifier boils down to the same—they are for our continued good health!

But, these two devices do very different things. How do we know which one is good for us, and what are the differences in energy consumption?

In order to find out which device we need, let’s start with what humidifiers and dehumidifiers do. The answer is all in the name.

What is a Humidifier?

In the U.S. market, roughly 8,000,000 portable humidifiers are sold each year. And with good reason. The culprit on trial here is dry air, which can cause sinus congestion, sinusitis, and dry skin. The device brings moisture into the air, thus making the room or location more “humid.”

Types of Humidifiers and How They Work

Portable humidifiers move water into the air using three primary methods. They are:

1. Ultrasonic humidifiers — They use something called a diaphragm, which is small and either metal or ceramic. The diaphragm oscillates at an ultrasonic frequency which makes the water splash into tiny droplets turning it into a very fine mist. A small fan blows this mist from the device. Ultrasonic humidifiers produce enough mist to humidify medium-sized (500 sq. ft.) rooms, however, most models are sized and meant for bedrooms.

2. Cool mist humidifiers — These work in two ways:

  • Dry room air is blown across an internal wicking material in order to evaporate moisture into the air.
  • Impeller humidifiers, fling water at a diffuser (using a rotating disk) which breaks up the droplets into a mist. The fan in the rotating disk then blows the mist out.

Cool mist humidifiers use very few parts so they usually inexpensive. In fact, half of all portable humidifiers sold in the U.S. are of the cool mist variety.

3. Warm mist humidifiers — These heat water into steam. As you may have guessed, creating steam requires more energy than ultrasonic or cool mist humidifiers.

On the other side of this coin are the dehumidifiers, which makes the air less humid by taking the moisture out of it.


As opposed to dealing with dry air, dehumidifiers are for when indoor humidity becomes too high. If this happens for extended periods of time, germs and molds will begin to grow and flourish. That can be dangerous for our health, which is why home ventilation is of the utmost importance.

This is not always possible. Some homes and residencies are not ventilated well enough to remove excess moisture successfully. That’s where a dehumidifier comes in. Non-electric devices are great for small spaces, while electric dehumidifiers are better solutions for larger spaces. So, how do dehumidifiers work?

Types of Dehumidifiers and How They Work

First, a metal surface is cooled. Humid air that comes into contact with the metal surface also cools down. From there, water starts to condensate on the metal. That’s because cold air contains less moisture than warm air. The accumulated condensation is collected in a bucket, which should be emptied regularly. Most electric dehumidifiers work in this way, however differences in efficiency vary widely.

Naturally, large devices are often more efficient than smaller ones. However, consider the size of your space. If you have a moisture problem in a small area, you might want to consider a non-electric dehumidifier.

What’s Best For Me?

Whether your problem lies with dry air or humid air, you want to make sure you’re buying the most efficient, cost-effective product.

The energy costs and efficiency of running a portable humidifier or dehumidifier vary depending on how long you use them and at what frequency. If you run it several times a day, and at night, over weeks, even years, it has the potential to use a lot of electricity. The type and size will dictate your energy needs. Here are some final things to think about when buying:

  • Effectiveness: This is based on how much water is being put into the air or being pulled out of it (the higher the output, the more effective the machine)
  • Coverage: Cool mist and ultrasonic humidifiers use fans, which makes them better at filling room space more quickly
  • Energy-Saver: Some units, even though they have stopped running, use a sort of “vampire power” so be sure to turn off your machine completely or unplug it, otherwise it will still use power
  • Clean Machine, Clean Mind, Heart and Health: Humidifiers need to be cleaned frequently so they don’t grow mold or bacterial growth—especially since you’ll be breathing in that air!
  • Noise: How much noise does the machine make? Electric dehumidifiers tend to do this, so make sure to try before buying!

For both products consider the size of the room, how much dry/humid air is entering the space, how long you’d need to keep it on, and the kWh rate the power company charges you. Remember to consider the size of the space and the machine, and try to match accordingly.

Resources— EnergyStar, Directenergy, Pingi