Need Appliance Repair Help? Ask a Technician for Answers ASAP

Ask an Expert, Get an Answer ASAP!

Dehumidifier Maintenance

Excessive moisture in your home can cause odors, health issues, and possible structural damage. Dehumidifiers help remove excess moisture and promote healthy humidity levels in your living space. You can use a small portable unit for problem areas or use a large unit that connects to your existing Heating, Ventilation, and Air Conditioning (HVAC) system. Regardless of which type of unit you use, it is important to keep your dehumidifier in top running condition.

Understanding how a dehumidifier works

A dehumidifier removes moisture from the air, which reduces humidity levels in your home. Lowering moisture levels deters mold and mildew growth and can reduce the effects of asthma, allergies, and other respiratory issues. Using a dehumidifier will also get rid of musty smells and provide a more comfortable living space for you and your family, especially if you live in a humid area.

Components and function

A dehumidifier has four main components: a fan compressor, reheater, cooling coils, and a reservoir. These parts work together to remove moisture from the air, much like an air conditioner.

 First, a fan draws room air into the dehumidifier. Next, the air contacts the coolant-filled cooling coils. Excess moisture in the air condenses on the coils and drips into the unit’s reservoir, which collects and stores the water.

The next step is where air conditioners and dehumidifiers differ. An air conditioner returns cooled air to the room. However, a dehumidifier uses the heat stored in the reheater to raise the temperature of the air. The air that exits the unit is warm, not cold. This cycle continues until the room reaches the desired humidity level or until the reservoir is full.

Taking care of your dehumidifier

To ensure your dehumidifier is in proper working condition, it is imperative to keep it clean. Clean the air intake, exhaust grills, and water collection tank on a regular basis.

Cleaning the water tank

It is important to empty the water tank regularly to avoid mold and mildew growth. Unchecked, the dehumidifier can spread these allergens throughout your home. You can clean the tank with soap and water or a mild disinfectant. Make sure you power off the unit before you remove the tank. Clean the reservoir tank at least once a month. However, some units require more frequent cleaning, so check your owner’s manual for the recommended cleaning schedule.

Cleaning the exhaust and air intake

You should clean the exhaust grills and air intake at least four times a year to avoid dust build-up and blockages. Failure to keep these areas clean may damage the unit or reduce the machine’s effectiveness. Use a brush-tipped vacuum attachment to sweep away dust.

Recharging dehumidifier coolant

In the past, you could go to your local hardware store and buy a recharging kit, hook it up to your dehumidifier, then follow the steps on the package. Most appliances used R-22, which is now strictly regulated. If your dehumidifier uses R-22, you need to contact a repair service and have a licensed technician recharge it.

Newer model dehumidifiers use R-410A, which is often called Puron. Puron is comparative to R-22, but is safer for the environment, less expensive, and has fewer issues than other coolant products.

Other options

Alternatively, you may need to install a conversion kit that uses a more environmentally friendly gas or buy another dehumidifier. Most dehumidifiers have a label that shows which coolant to use. If the coolant is not listed, check it for the manufacturing date. Models made before 1995 were charged with R-22 coolant.

Cleaning coils and filters

Condenser coils can build up a layer of frost or ice when you use the dehumidifier during colder months. Frost and ice can cause your unit to run improperly or stop working.

Check the warranty

Before you open the dehumidifier, check your owner’s manual to see if it is still under warranty. You could void the warranty by accessing internal parts. If you have any doubts about the warranty aspect, call the manufacturer for information.

Defrosting the unit

To inspect the coils, turn the unit off and unplug it from the power source. If ice or frost is present, the room temperature is probably too cold for the dehumidifier to run correctly. The owner’s manual should have instructions on how to deal with frost build-up. Increasing the temperature of your home will help remove the frost and ice.

Preventing frost build-up

The only way to completely avoid frost build-up is to buy a newer model dehumidifier that has an automatic defrost setting. Models with this setting will shut the compressor off and allow the fan to continue running, which melts any ice build-up. Once the defrost cycle is complete, the unit will automatically resume operation.

Cleaning the air filter

To clean the air filter, remove the front cover of the machine and take the filter out. Check the filter for damage. If the filter is extremely dirty or worn, replace it. Your owner’s manual may have specific cleaning instructions; if you do not follow them, it may void your warranty. If your filter is in good shape but dusty, you can soak it in a mixture of warm water and bleach for a few minutes, then rinse it. Allow the filter to dry completely before placing in back into the machine.

Setting the humidistat

Your dehumidifier has an automatic humidistat that you can set to your comfort level. Once the humidistat is set, your dehumidifier will cycle on until the desired humidity level is reached. At that point, it automatically turns off. It will cycle on as humidity levels rise again.

Determining the correct humidity level

Some humidity is good. Moisture in the air can help prevent nosebleeds and dry skin. It also reduces the amount of static electricity in the area. If the air gets too dry, it can even damage wood floors or cause paint to crack.

Setting the humidistat too high can make the air in your home or office very dry. It is also more expensive to run your dehumidifier all the time. HVAC professionals recommend a setting of around 35% humidity to avoid dry air problems.

Setting older dehumidifiers

If you have an older model dehumidifier, the unit will have a humidity control setting. The settings range from 1-10, with 10 being the highest level of dehumidification. Set the control and the dehumidifier will automatically start and stop as humidity levels fluctuate. During times of high humidity, your dehumidifier may run continuously. This is a normal operational procedure to ensure proper humidity levels. Humid air from outside and the use of your clothes dryer can bring outside air into your house, which can affect moisture levels in the home.

Calibrating humidity settings

It is a good idea to monitor humidity levels to ensure your dehumidifier is working correctly. You can purchase a battery-powered hygrometer online or at a home improvement store. Prices begin at around $20. The units typically display both temperature and room humidity. If the humidity level on the hygrometer does not match the humidistat setting on your unit, you may need to troubleshoot it. Talk to a verified HVAC technician if you need help.

Ensuring the quality of air in a home or office is a must for most people, especially those who suffer from allergies or other respiratory issues. Dehumidifiers reduce humidity levels and lower the number of allergens, dust mites, mold, mildew, and odors in the home. For optimal results, regular dehumidifier maintenance is important. Monitor your home’s humidity level and keep the dehumidifier clean to keep your unit in top shape.

Please type your question in the field below

3 verified Appliance Technicians are online now

Appliance Technicians on JustAnswer are verified through an extensive 8-step process including screening of licenses, certifications, education and/or employment. Learn more


Home Appliance Technician

Vocational, Technical or Trade Scho

13453 positive reviews
Tom Goellner

Home Appliance Technician

Vocational, Technical or Trade Scho

1544 positive reviews
Tyler Z.

Appliance Doc

Bachelor's Degree

81653 positive reviews
See all Appliance Technicians
JustAnswer in the news:
Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.
Web sites like
...leave nothing to chance.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.