If you're just starting your search for a dehumidifier, you may have questions - or you may be wondering which model is right for your space.
Review our list of frequently asked questions about dehumidifiers to understand our most common customer questions.
Frequently Asked Dehumidifier Questions
- How do dehumidifiers work?
- How do I know if I need a dehumidifier?
- What is the ideal indoor humidity level?
- How many dehumidifiers do I need?
- Where is the best place to put a dehumidifier?
- How long do dehumidifiers take to work?
- What features should I look for in a dehumidifier?
- How much do dehumidifiers cost to run?
- Do dehumidifiers shut off automatically when they're full?
- How do I maintain a dehumidifier?
- What is the difference between dehumidifiers & humidifiers?
- How loud are dehumidifiers?
How do dehumidifiers work?
Our most common customer question is: How does a dehumidifier work? Some customers don't understand what a dehumidifier does. Their designs are pretty simple.
- Pulling in damp air into the unit
- Cooling it with a condenser removes moisture from the air. The moisture is collected in a bucket inside the dehumidifier.
- Redistributing the dry, dehumidified air back into your environment with its fan.
Dehumidifiers are typically placed in troubled areas with high humidity, such as basements, bathrooms, crawl spaces, bedrooms, and commercial areas.
How do I know if I need a dehumidifier?
Dehumidifiers are the best way to remove excess moisture from your home and avoid issues caused by high humidity levels. These include:
- Mold and musty scents
- Warm, clammy, and uncomfortable conditions
- Condensation on windows
- Uneven floorboards or structural damage
If these problems are ignored, allergic reactions, respiratory problems, and other health issues can occur. Avoid them by maintaining a healthy humidity level with a dehumidifier.
What's the ideal indoor humidity level?
The ideal humidity level for homes is 45 to 50 percent. Relative humidity levels above 50 percent can create an environment where mold spores, dust mites, bacteria, and even harmful pests thrive.
A relative humidity level below 30 percent can be just as damaging. It can increase the number of cold and flu viruses, irritated skin and respiratory passages, cracked ceilings, separated wood floors, and more.
Look for dehumidifiers with humidistats, which automatically maintain your set room temperature. Questions about relative humidity? Check out our full article on the topic here.
How many dehumidifiers do I need?
Dehumidifiers are designed and sized to operate effectively for a room type or room size based on a range of square footage. Only in very large spaces should more than a single dehumidifier be needed to adequately lower the humidity level. Be sure to purchase a unit large enough to cover the space. Don't try to get by with a small room dehumidifier to remove moisture from a crawl space or unfinished basement area.
Should a large area require dehumidifying, a desiccant dehumidifier may be a better option than a standard or refrigerant unit. Desiccant dehumidifiers continue to remove moisture the longer they operate, so the humidity level will continue to drop. However, they do take longer to achieve lower humidity levels.
Where is the best place to put a dehumidifier?
Placing your dehumidifier depends mostly on where the humidity problem exists. This could be in a living space, in a finished or partially finished basement, or in a crawl space.
Sizing a dehumidifier is extremely important to make sure it works properly for your space. Consider the room size covered, or shop by the room type (crawl space, basement, etc).
Browse both dehumidifier options below:
Dehumidifiers by Room Size
- Small Room Dehumidifiers: These dehumidifiers are designed for moisture control in rooms up to 500 square feet. They're best suited to treat small, damp spaces like bedrooms or offices.
- Medium Room Dehumidifiers: These dehumidifiers are great for dehumidifying damp medium- to large-sized spaces up to 1,000 square feet.
- Large Room Dehumidifiers: These dehumidifiers treat a wider range of humidity problems, from excessively wet to damp conditions. This size is perfect for large basements, crawl spaces, bedrooms, and more, up to 1,500 square feet.
- Whole-House Dehumidifiers: A whole-house dehumidifier can be integrated with a home's existing HVAC system. Many of these dehumidifiers can remove excess moisture in spaces up to 3,000 square feet.
For a deeper look at the factors involved with the right size dehumidifier, see our How to Size Your Dehumidifier article.
Dehumidifiers by Room Type
Capacity isn't the only variable to take into consideration; depending on the type of space you want to dehumidify, there are specific models designed for these spaces.
- Crawl Space Dehumidifiers: Designed to tackle moisture problems in tight crawl spaces.
- Basement Dehumidifiers: Consider a reliable basement dehumidifier if your basements have musty smells or other moisture issues.
- Living Area Dehumidifiers: These single-room dehumidifiers are ideal for use in bedrooms, living rooms, and other rooms.
How long do dehumidifiers take to work?
Depending on where moisture needs to be removed, a dehumidifier may take a few hours for smaller to medium-sized single rooms or up to 10 to 12 hours for larger areas. Most have an onboard or built-in humidistat that can be set to maintain a specific humidity level.
What features should I look for in a dehumidifier?
In addition to capacity, coverage area, and type of humidity problem, dehumidifiers also have a variety of features that make operation convenient and simple:
- Digital Humidistat: Look for a dehumidifier with a digital humidistat for set-it-and-forget-it moisture control. It will automatically adjust to maintain your set humidity level.
- Internal Condensate Pump: Purchasing a dehumidifier with an internal condensate pump is the most convenient way to remove moisture. The pump automatically pushes moisture up and out of the units.
- Wi-Fi Capable: Smart Wi-Fi Dehumidifiers are designed to make maintaining a consistent humidity level simpler, even from a remote location. Some also feature voice control using Alexa or Google Assistant.
How much does it cost to operate a dehumidifier?
The cost of operating your dehumidifier depends on the appliance, the amount of time it is operating each day, and your electricity rate. In general, you can expect to spend $5 to $30 each month on electricity costs.
- Look for an Energy Star-rated dehumidifier for operation at 15 to 20 percent less cost than non-rated units.
- Purchase a dehumidifier with a large enough capacity to handle your humidity problem. Purchasing a smaller, lower-priced dehumidifier can result in higher energy costs if the appliance has to run continuously to remove excess humidity.
Do dehumidifiers shut off automatically when they're full?
Some room models will do this; however, it's always best to double-check the individual unit you're considering. Another consideration is an internal pump for draining instead of having to empty the condensate bucket at intervals.
Large crawl space or basement dehumidifiers require continuous draining, and some include an internal condensate pump that provides lift to move condensate more easily.
How do I maintain a dehumidifier?
Maintenance is fairly simple and includes cleaning or replacing the air filter when needed and cleaning out the condensate bucket with warm water and a mild detergent to prevent mildew growth.
What is the difference between dehumidifiers and humidifiers?
While this can be confusing, the answer is simple. Dehumidifiers remove unwanted moisture from indoor air, while humidifiers add moisture to very dry air. For additional information on humidifiers, see our humidifier buying guide.
How loud are dehumidifiers?
As with any appliance that uses a fan, the higher the fan setting, the more noise you can expect. Dehumidifiers also use a compressor, which makes slightly more noise than a fan. When the compressor is operating, users should expect an increase in noise.
On lower settings, the noise is comparable to white noise. Commercial-grade dehumidifiers are louder than single-room dehumidifiers. Luckily, they're typically in basements, crawl spaces, and industrial settings where noise isn't a primary concern.
If you know your dehumidifier's decibel rating, you can use this chart to get an idea of what it means:
| Decibel Comparison Chart | |
|---|---|
Decibels (dB) |
Source |
10 dB |
Empty Room (No people or running appliances) |
20 dB |
Breathing |
30 dB |
Whisper |
40 dB |
Stream |
50 dB |
Refrigerator |
60 dB |
Conversation in a restaurant or office |
70 dB |
Dishwasher or Shower |
80 dB |
Kitchen Blender |
- 0-30 decibels (dB) is considered Very Quiet.
- 31-60 decibels (dB) is considered Quiet.
- 61-80 decibels (dB) is considered Annoying.
- More than 80 decibels (dB) is considered Potentially Damaging.
In Summary
When considering the purchase of a dehumidifier, many questions may arise, from size to special features to condensate draining. Other questions include noise level, cost, and placement.
Still Have Questions?
We know choosing a dehumidifier isn't an easy decision. To learn more about dehumidifiers, visit our Dehumidifier Knowledge Center. Not sure what's best for you? We can take the guesswork out of decision-making with our product-finding wizard. You'll have suggestions after answering three simple questions.
Call us at 1-800-934-9194. We want to help make your indoor space healthy and comfortable.
