How Much Energy Does My Humidifier Use?
To help you understand very basic electrical consumption calculations, you’ll need to keep a simple equation in mind: Volts (V) x Amperes (I) = Watts (W). What you’ll discover is how just how small appliances can contribute to your home’s energy usage and how these little conveniences can make big differences on your bill.
How Much Energy Does a Humidifier Use?
Roughly 8,000,000 portable humidifiers are sold annually in the U.S. market, most to relieve discomfort associated with dry air, such as sinus congestion, sinusitis, and dry skin. Running a portable humidifier over the course of several hours, overnight for weeks at a stretch for example, has the potential for using lots of electricity — depending on the type and size.
How do humidifiers work?
There are three primary methods your average portable humidifier uses to move water into the air:
- Ultrasonic humidifiers use a small metal or ceramic diaphragm that oscillates at an ultrasonic frequency to splash the water into tiny droplets that make a very fine mist. This mist is then blown from the humidifier with a small fan. While ultrasonic humidifiers can put out enough mist to humidify a medium sized (500 sq. ft.) room, most models on the market are sized to work in bedrooms.
- Cool mist humidifiers work in two ways: 1) Blowing dry room air across wet wicking material to evaporate moisture into the air; and 2) Impeller humidifiers use a rotating disc to fling water at a diffuser that breaks up the droplets into a mist, and a fan incorporated into the rotating disk blows the mist out. Both kinds of humidifiers involve few components, so they tend to be very inexpensive. About half of all portable humidifiers sold in the US are the cool mist kind.
- Warm mist humidifiers heat water into steam. Making steam uses more energy than ultrasonic or cool mist humidifiers.
What else do I need to know about humidifiers?
The higher the output of water into the air, the more effective the humidifier. Therefore, efficiency is the energy, in watt-hours, required to emit a gallon (or liter) of water into the air. Since both cool mist and ultrasonic humidifiers incorporate fans, they are much better at filling room space more quickly.
While air technically occupies three-dimensional areas measured in cubic feet, it’s easier for people to understand their home’s room sizes in square footage.
Most humidifiers with convenient electronic controls (timers, humidity sensors, stored presets) will use some standby or “vampire” power. For example, one common feature is when the humidifier will go into standby mode once the supply tank runs out of water or the desired humidity level in the room is reached. This leaves the humidifier “on” even though it is not running, which uses a certain amount electricity just waiting. Depending on the controls, turning the unit completely off or unplugging it when you leave the room or leave home will reduce its energy usage.
Time to Compare
Before we begin, gallons/hour reflect gallons of water evaporated during full runtime. For comparison reference, decimal amounts break down:
- One gallon= 1.00
- One quart = .25
- One pint = .125
- One cup = .0626
Let’s check out these three models:
- The Honeywell HCM-350 cool mist humidifier uses a wicking method. It moves about two gallons (7.6 liters) output per 24 hours (.083 gallons/hour) covering 500 sq. ft. It uses about 50 watts.
- The V750 Vicks Warm Mist Humidifier will steam 1 gallon (3.78541 liters) into the air in about 12 hours (.083 gallons/hour), covering roughly 1,000 sq. ft. It uses 260 Watts.
- The TaoTronics Ultrasonic Humidifier Cool Mist TT-AH001 moves 1.05 gallons (4 liters) into the air during a run-time of 15 hours (.07 gallons/hour), covering 538 sq ft. It uses 30 watts.
Even though the V750 moves .083 gallons into the air/hour, the same volume as the Honeywell HCM-350, it uses much more energy because it heats the water. So in the spirit of being energy-efficient, we aren’t going to analyze this model further.
Both the Honeywell HCM-350 and the TaoTronics TT-AH001 can cover around 500 sq.ft. Both deliver roughly the same volume of mist; the former makes .083 gallons/hour, while the latter creates .07 gallons/hour. But while you might just get a sliver of mist faster with the HCM-350, you’ll use 20 watts more than the TaoTronics TT-AH001.
Assuming 10¢ per Kilowatt-hour (kWh), the costs over three months stack up this way:
- Honeywell HCM-350: 50 watts x 10 hours/day= 500 watt-hours. 500 Wh x 90 days = 45,000 Wh (45 kWh) x .10/kWh (cost) = $4.50/ three months
- TaoTronics TT-AH001: 30 watts x 10 hours/day= 300 watt-hours. 300 Wh x 90 days = 27,000 Wh (27 kWh) x .10/kWh (cost) = $2.70/ three months.
The ultrasonic is cheaper to run. If you need it to run longer than 3 months out of the year, the savings difference could grow larger.
Different humidifier types have specific benefits. For example, cool mist and ultrasonic humidifiers need to be cleaned frequently to prevent mold or bacterial growth — which you don’t want misted into the air you breathe. Warm mist types (like the aforementioned Vicks V750) are better at killing off mold and bacteria because they heat the water – but they also use much more energy.
So while it’s important to pay attention to energy costs as you shop for a humidifier, remember that in most cases you’re looking for a solution to a health problem. It’s important to begin by identifying your needs and selecting the type of humidifier to best address them, and then to compare the efficiency of different models.