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.
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.
There are three primary methods your average portable humidifier uses to move water into the air:
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.
Before we begin, gallons/hour reflect gallons of water evaporated during full runtime. For comparison reference, decimal amounts break down:
Let’s check out these three models:
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:
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.