Dehumidifier Buying Guide

Dehumidifier buying guide

If you have high humidity in your home then you should use a dehumidifier. These appliances remove moisture and help keep desired humidity level. Keeping a balanced humidity limits mold growth reduces uncomfortable muggy conditions, and protects your home from damage.

Dehumidifiers are available in a variety of sizes and moisture removal capacities. Many models have a lot of good features that make your life easier. We have made this guide to help you understand how big and advanced model you may need.

Why Should You Use A Dehumidifier

Recommended indoor humidity level is between 30 and 50 percent. If a humidity level is higher than 60 percent than it is considered high and you should reduce it by 30 to 50 percent. And the best way to reduce a humidity level is using a dehumidifier.

Lowering a humidity is not the only reason why you should use a dehumidifier. There are other reasons too.

Preventing Mold and Mildew Growth. The best way to stop a mold or mildew problem before it even happens is to maintain a healthier humidity level all the time. Mold and mildew spores grow and reproduce in warm, wet conditions above 60 percent. The areas that are sensitive to mold infestations are basements, bathrooms, and kitchens. Use a dehumidifier regularly in these areas to help keep them dry and mold-free.

Managing Allergies. High moisture can increase common household allergy triggers like dust mites, mold spores, and airborne bacteria, all of which can grow and reproduce quickly in humid conditions. Keep humidity level between 30 to 50 percent to make your space less hospitable to these allergy triggers and help you better manage your allergy symptoms.

Pest Control. Pests, for example, spiders, cockroaches, silverfish, centipedes loves moist conditions. Keeping a drier space repels these disturbing critters and keeps them out of your home for good.

Supplement Your Air Conditioner. Feeling chilly in your home lacks two things: cool air and dry air. Use a dehumidifier to improve your central air conditioner keep the air dry and free your AC from running overtime to try to cool your humid space.

Home. Moisture makes damage to your home for example support beams, buckling floorboards, hardwood floors etc. Keep the humidity level below 60 percent to prevent costly repairs.

Ideal Place for a Dehumidifier

Dehumidifiers are excellent solutions for a variety of places in your home, from your kitchen to your basement or garage.  See a list of typical areas where you might use a dehumidifier:

  • Basements
  • Crawl spaces
  • Kitchens, bathrooms, and laundry rooms
  • Bedrooms
  • Garages and workshops
  • Spa and indoor pool areas
  • Warehouses and other industrial/commercial spaces
  • Water-damaged areas

How Dehumidifiers Work

By their operation, dehumidifiers remove water from the conditioned air.


This is the most common type. A fan sucks moisture in through a dehumidifier inlet. A humid air passes over freezing cold tubes through which a coolant circulates. As the air cools, the moisture it contains turns back into liquid water and drops down off the tubes. Then the free of moisture air passes over a heating element and warms back up to its original temperature and blows back into the room through the outlet. The moisture that was in the air originally drops down into a bucket at the bottom of the machine and when it is a full dehumidifier automatically turns off and switches on an indicator light telling you the machine needs emptying.

If you want to read about all other methods of dehumidifiers please visit this place. 

Which Type of Dehumidifier  Do You Need?

Dehumidifiers are available in 2 main types: residential and commercial/industrial models.

Residential dehumidifiers Whynter RPD-311DW Elite D-Series Energy Star Portable Dehumidifier, 30-Pint

For separate spaces like basements or bathroom, the best are residential dehumidifiers. They are portable, available in small, medium, and large moisture removal capacities. Usually, these dehumidifiers have a lot of features such as electronic control panels, multiple fan speeds, casters, onboard humidistats, water buckets, and maybe Energy Star-qualified.

Whole House Dehumidifiers

If you’re looking to keep your whole home or a large office space dry and healthy then you should use a whole house dehumidifier. Ducted whole house dehumidifiers connect directly onto your HVAC system and dehumidify the air as it’s cooled. Dry, cool air is then dispersed everywhere in your home through your ductwork.

You may also choose standalone whole house dehumidifiers. They are portable, easy to setup and operate. It’s critical to place them in a centralized location in the practice space for the most efficient dehumidifying.

Commercial/industrial dehumidifiers

Commercial dehumidifiers bigger and heavier-duty units that are made for more unforgiving dehumidifying jobs. These dehumidifiers have a huge moisture removal capacities and can operate in extreme conditions. These models have features such as low-temperature operation internal condensate pumps, loss of power protection, and simplified controls. You might use an industrial dehumidifier to help remove moisture in a flood-damaged space or to control humidity in an indoor pool area, for example. Some small industrial models are also more effective choices for residential basements and crawl spaces.

Choosing the Right Size Dehumidifier

A dehumidifier’s size is defined by its total ability to remove moisture. Capacity is rated in pints of moisture removed per day, or 24-hour period. All dehumidifiers have stated how many pints of moisture they can remove. You may have a question how to know if you need for example 30 pints per day or 70 pints? You can convert pints to square feet. But to do that you have to know at least how damp is your space. Is it only a little damp, moderately damp, very damp or extremely wet?

A little damp space has a 50 to 60 percent humidity. It feels damp and has an occasional musty smell.

Moderately damp space often feels damp and often smells musty. Humidity level is between 60 and 70 percent.

The very damp place feels wet, smells musty; damp spots appear on walls and floors. Humidity is between 70 to 85 percent.

Extremely wet space feels wet, smells musty; seepage appears on walls and floors; may have mold growth. Humidity is between 85 and 100 percent.

To help simplify your selection in size, take a look at sizing chart below:

The condition
of the space

Up to 500
Sq. Ft.

Sq. Ft.

Sq. Ft.

Sq. Ft.

2001+ Sq.

A little damp


20 pints

25 pints

35 pints

45 pints

60+ pints

Moderately damp


25 pints

30 pints

40 pints

55 pints

70+ pints

Very damp


30 pints

35 pints

50 pints

 65 pints

80+ pints

Extremely wet


35 pints

40 pints


75 pints

90+ pints

Capacity at AHAM vs. Capacity at Saturation

There are two ways of testing conditions how manufacturers may rate the moisture removal capacities of their dehumidifiers.

AHAM conditions are average humidity conditions of 60% humidity, 80 degrees F. These testing conditions are recommended by the Association of Home Appliance Manufacturers (AHAM) in order to ensure a more realistic expectation for how a unit will function in the vast majority of spaces, which tend to have average humidity levels most of the time.

Saturation conditions are more extreme humidity conditions of 100% humidity, regardless of the temperature. Manufacturers use these testing conditions to estimate the maximum amount of moisture a dehumidifier can extract per day.

This makes a dehumidifier choice a bit complicated. Because when you search for a dehumidifier you have to think about the testing conditions each model might have been rated in. A dehumidifier that’s able to remove 90 pints of water in saturation conditions (100% humidity) will only remove around 50 pints of water in AHAM conditions (60% humidity). That is because a dehumidifier extracts less water in the drier air than in more humid conditions. Be sure to keep testing conditions in mind when you’re judging models. If you are searching a dehumidifier for a very wet space, look for a unit that is tested at AHAM. It will be more robust than a model rated at saturation.

Draining Your Dehumidifier Friedrich D70BP 70 Pint Dehumidifier with built-in drain pump, Front Bucket and Continuous Drain

Dehumidifiers that use refrigeration systems to contract moisture have to get rid of the accumulated moisture somehow. This is where draining comes in. There are 3 main methods of draining a dehumidifier and most models can be configured for at minimum 2 of these methods. That gives you more versatility to choose the system that works well for you. 

  1. Empty the Water Reservoir – The simplest way to remove collected moisture is by emptying a dehumidifier’s water reservoir if it has one.  Moisture collects in the unit’s tank until it reaches capacity. Then you have to remove the reservoir and empty it. Most dehumidifier reservoirs are designed like drawers that you’ll slide out with ease. Some also have handles to make them easy to carry back and forth for emptying.
  2. Gravity Drain – Most dehumidifiers also have a gravity draining hose port integrated into the design. This allows you to connect a hose, either a standard garden hose or one that’s included with the dehumidifier, and let the unit drain water out automatically. For this method, you’ll need to point the hose down and let gravity do the work. If needed, you can tilt the dehumidifier to help the process along. Route the drain hose to a nearby floor drain or another suitable location.
  3. Internal Condensate Pump – Some dehumidifiers have an internal condensate pump that is intended to pump moisture out automatically. This method is ideal if you’d prefer to pump moisture vertically to a sink or outside a window, for example. All you have to do is connect your hose to the pump port, route the hose to your selected location, and let the pump do the work.

External Condensate Pumps

If a dehumidifier is equipped with gravity drain it can be used with an external condensate pump as well. This is a special accessory that works exactly like an internal condensate pump, pumping moisture out of the water reservoir. To use, you have to attach a hose from the gravity drain port on the dehumidifier to the pump. Then, you have to route another pipe from the pump to your chosen draining location.

Features to Look For Whynter RPD-702WP Energy Star Portable Dehumidifier with Pump, 70-Pint

Almost all dehumidifiers have a lot of features to add comfort to your life and help the unit best fit your needs. Most of the popular features you can see below:

Automatic Humidistat. Best feature out there. A humidistat automatically maintains your desired level of humidity by triggering the dehumidifier to run only when needed. Helps to save energy.

Programmable Timer let you program startup and shutoff times. Great if you don’t have time to turn it on or off.

Various Operating Modes and Speeds – Pick from multiple speeds and modes to find the best level of dehumidification for your needs.

Casters and Handles. Most of the dehumidifiers are quite large and that is why they have casters and handles. Also, almost all of units which have water containers have them with handles.

Automatic Restart. Dehumidifier automatically restarts on power failure. Great feature.

Low-Temperature Operation. Most residential dehumidifiers operate successfully down to 41 degrees F. Look for this feature if you’re going to use your unit in a cooler crawl space or basement.

Automatic Defrost. In freezing temperatures, automatic defrost helps maintain your unit operational by defrosting any ice accumulation to reduce downtime.

Air Filter. Most household dehumidifiers have a washable air filter that catches allergens and particles and protects the unit’s internal components from damage caused by debris.

Dehumidifier Noise Level

Most of the dehumidifiers, especially those with compressors and fans, work by moving air through them. And this process can be quiet only when moving a low amount of air. As soon as these dehumidifiers start to move a decent amount of air they become noisy. How loud will be this noise depends on the model. Some of them have a quiet operation (at least they presents them as quiet). With these models, manufacturers have taken several steps to reduce noise by isolating the fan or using a smoother-running fan, for example.

Dehumidifier noise level is measured in decibels (dB). For example, dB rating around 40-50 is comfortable to talk over, but of course, you will hear it. How sensitive you are to the noise will mainly depend on where you are putting it. You are less likely to hear your dehumidifier if you are using it in a basement while you are upstairs, for example.

Fan Operation

Dehumidifier with a fan has two operation possibilities. One is when a dehumidifier fan runs continuously and one is when the system is actively dehumidifying. Which is best and more efficient? Read further.

Fan Runs Continuously. With this operation, the fan is always on whether the compressor is running or not. The manufacturers of these models think that a continuously-running fan helps move air continuously past the humidity sensor (if equipped) so that the dehumidifier measures a more accurate humidity level in the room.

This helps the unit set fan speed and keep your desired humidity level consistently. In addition, a continuously running fan helps redistribute dehumidified air more efficiently throughout your room for even coverage. Some people might be worried about the amount of energy consumed by the running fan. But this shouldn’t be too significant of a concern since a dehumidifier fan uses only about as much energy as a light bulb on average.

Fan Runs Only When Dehumidifying. During this operation the fan cycles off when the compressor turns off. The fan can cycle off immediately with the compressor or after a short few-minute delay after the compressor shuts off. These dehumidifiers save energy and help make the unit more efficient. That is what manufacturers say. But the energy savings will be minimal because dehumidifier fans are not supposed extreme energy consumers.

So you still don’t understand which is really more efficient? Due to the fact that dehumidifiers with fans that run only when dehumidifying only save a small amount of energy we would choose a dehumidifier with a continuous running fan. These models will more accurately sense your room’s humidity level and adjust operation accordingly, so you’ll get the best results and you’ll stay within your energy budget.

Dehumidifier Maintenance
DeLonghi DD45PE 45-pint Dehumidifier with Patented Pump

Usually, dehumidifiers are trouble-free, but they do require maintenance. You will have to empty the water tank, clean the unit periodically to keep your home free of extra moisture, dust, and air pollutants such as mold and mildew that can be possibly harmful to your health. That will also help prolong your dehumidifier life and overall performance.

Here are some tips for better maintenance:

  • Place your dehumidifier at least 6 inches (15.24 centimeters) apart from a wall so it does not block air inlet or outlet.
  • Close doors and windows. Keeping your doors and windows open will decrease the effectiveness of your dehumidifier in that area and may also raise your energy bill.DeLonghi DD45PE 45-pint Dehumidifier with Patented Pump
  • Wait for at least 10 minutes to power your dehumidifier back on after turning it off. Some dehumidifiers have an automatic time delay before they start running again. Powering your dehumidifier off and on right away may cause your dehumidifier’s compressor to overheat.
  • Clean dehumidifier regularly. If it has a filter clean it at least once per year. Clean the filter as the manufacturer has stated in the user manual.
  • When emptying water tank, scrub the inside of it with a brush using soap and water or use a disinfectant spray and paper towels.
  • Oil your dehumidifier’s fan motor on a regular basis using 3 drops of lubricating oil to keep your fan running smoothly and quietly.
  • Dehumidifiers can last from 3 to 15 years. Performing the recommended maintenance and keeping your unit in great condition improves lengthen the operating lifespan.


I hope this guide helped you. I will not get offended if you didn’t read it.

Hope you have much more understanding about dehumidifiers. What next? You can continue with my dehumidifier comparison charts and reviews. I have lots of valuable information in these pages. Just use the links below to read them.


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My name is Ryan. I have had a hard time dealing with my allergies. Happily, I found that an air purifier was effective to ease my allergy symptoms. I spent a lot of time researching the best air purifier. I know how hard it can be to find the suitable one.

During the reading period, I also read a lot about humidifiers and dehumidifiers. I learned the mechanisms behind the technologies as well as the manufacturers and organizations within the industry.

I now feel convinced that I have built a guide that shows you all you need to know about air purifiers, humidifiers, and dehumidifiers. So I came up with the idea of creating this website.

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