Humidifier vs Dehumidifier: What’s the difference?
Key takeaways:
• A humidifier adds moisture to the air.
• A dehumidifier removes moisture from the air.
• Whole-home solutions offer humidity control year-round.
By Anne Fonda
Home comfort is about more than how warm or cool the house is. The humidity level in your home plays a part, too. Simply put, humidity is the amount of moisture in the air.
The Environmental Protection Agency (EPA) recommends an indoor humidity level between 30% and 50% RH for optimal comfort and indoor air quality (IAQ). That’s because the EPA says humidity levels outside this range can create comfort and health problems.
High humidity (60% or higher) can lead to problems such as mold growth, an increase of dust mites, peeling paint, a musty smell, a clammy feeling, and decreased comfort.
Low humidity (under 30%) can cause dry skin, irritated sinuses, respiratory issues, static electricity, and decreased comfort.
What is a humidifier, and what do humidifiers do?
A humidifier is an appliance (portable or whole-home)that adds moisture to dry air. A portable room humidifier might be useful during an illness, while a whole-home humidifier is a more permanent solution to low humidity.
A whole-house humidifier connects to your home’s plumbing system, meaning you never have to fill a reservoir or clean it. Depending on the type, you would change a humidifier pad periodically or let your HVAC technician service the humidifier.
What is a dehumidifier, and what does a dehumidifier do?
A dehumidifier, on the other hand, is an appliance (portable or whole-home) that removes excess moisture from the air. A portable dehumidifier might be useful if you have basement flooding or a burst pipe, while a whole-home dehumidifier is a better solution for continuous high humidity in the summer or year-round.
A whole-house dehumidifier connects to a drainage system, such as a hose or pipe that takes the water outside your home. With continuous drainage, the whole-house unit won’t stop because it has filled a reservoir like you would with a portable unit.
Will a dehumidifier cool a room?
No. A dehumidifier does not change the room temperature. However, it can make a room or house feel cooler. It does this by reducing the humidity. Think about the difference in how you feel when you step outside on a fall afternoon when the temperature is 70°, and the humidity is 60% or lower, compared to what it feels like on a summer morning when it’s 70° and the humidity is 87%. The temperature is the same, but the higher humidity makes you feel hot and sticky.
Will a dehumidifier help with mold?
A dehumidifier can help prevent mold growth, but it cannot reduce or remove mold growth that already exists. If you suspect you have mold in your home, you should get your home tested by a certified company and arrange for mold remediation.
If your home is humid year-round, a whole-house dehumidifier can help reduce the humidity and increase your comfort, while protecting your home.
When to use a humidifier vs a dehumidifier?
Before using either one, you need to monitor the humidity level. We recommend the Awair Element indoor air quality monitor. It monitors humidity levels, indoor pollutants, and more. It can integrate with your HVAC system to automatically turn on the indoor fan, engaging your installed whole-house humidifier or whole-house dehumidifier when humidity levels go outside the optimal range.
When to use a humidifier
“Fan-powered humidifiers adjust from summer to winter to provide the right amount of moisture for your home at any time of year. There’s an interior fan to facilitate the evaporation of water that is released to drip down the inside panel when the thermostat sends a call for humidity. Your furnace or air handler then blows the air throughout your home.”
- Sean Goddard, Product Manager, Coils & Indoor Air Quality
You would use a whole-house humidifier in the winter when humidity levels drop, as the temperatures drop, drying the air out. Or, you might use the humidifier year-round if you live in an arid climate such as Phoenix, AZ or Las Vegas, NV. Follow your owner’s manual to set the appropriate humidity level on your thermostat.
In areas with colder winters, the outdoor temperature will dictate what you should set the humidity level at to prevent condensation. See the chart below from our humidifier owner’s manual.
| Outdoor Temperature | Recommended Indoor Humidity |
| +40℉ | 45% |
| +30℉ | 40% |
| +20℉ | 35% |
| +10℉ | 30% |
| 0℉ | 25% |
| -10℉ | 20% |
| -20℉ | 15% |
When to use a dehumidifier
“A whole-house dehumidifier can be installed as a standalone unit or connected to your existing ductwork to utilize your HVAC system fan. It’s an excellent solution for homeowners as part of a comprehensive solution in a high-humidity area.”
Sean Goddard, Product Manager, Coils & Indoor Air Quality
Run the dehumidifier anytime that the indoor humidity is creeping above 55%.
If you live in a high-humidity area such as Houston, TX, or Jacksonville, FL, you may struggle to keep your home comfortable. Depending on your HVAC system, your air conditioning system may struggle to remove humidity from the air in the hotter months. And when it’s cool enough that you don’t need the air conditioner, you still need to remove humidity from the air.
This is where a whole-house dehumidifier comes in. It can run independently of your HVAC system to remove moisture from the air.
Get an indoor air quality assessment
Interested in lowering or raising the humidity in your home? Need better ventilation? Check out our Indoor Air Quality Resource Guide to get an idea of the possibilities. If you want to breathe easier and improve home comfort, contact your local Trane dealer today.
Anne Fonda, Content Writer
A Content Writer with Trane Technologies, Anne Fonda researches topics and writes for Trane® and associated residential HVAC brands. She works in collaboration with Trane Technologies subject matter experts, offering easy-to-understand, informative content on complex topics. Her goal is to help consumers make informed decisions on the products and services they need.
She has written for HVAC and other service provider websites for over 16 years. Before transitioning to web content writing, Anne had a 14-year stint as an award-winning journalist. She graduated cum laude from the University of Missouri-Columbia School of Journalism.
When she’s not working, Anne enjoys playing word games, reading, gardening, spending time with family, and visiting gardens and museums.
Expert review by Sean Goddard, Product Manager, Coils & Indoor Air Quality
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