Why Is My Dehumidifier Blowing Hot Air

It's a hot, humid day, and you're relying on your dehumidifier to keep your home comfortable. But instead of cool, dry air, it's blowing hot air! This can be frustrating and concerning, especially when you're expecting relief from the humidity. Don't panic! Before calling a technician, let's walk through some simple troubleshooting steps you can take to diagnose and potentially fix the problem yourself.

Understanding Why Dehumidifiers Blow Hot Air

Dehumidifiers work by drawing in moist air, cooling it down to condense the moisture into water, and then reheating the air before releasing it back into the room. This process inherently generates some heat. However, if the air feels excessively hot, it indicates a problem that needs to be addressed.

Step-by-Step Troubleshooting Guide

Let's systematically investigate the possible causes of your dehumidifier blowing hot air. Remember to always unplug the dehumidifier before performing any maintenance or inspections.

1. Check the Power Supply

A basic but often overlooked step. Ensure the dehumidifier is receiving adequate power.

Is the dehumidifier plugged in properly? Double-check the plug connection at both the dehumidifier and the wall outlet.
Is the outlet working? Test the outlet with another appliance you know works. If the outlet is dead, check the circuit breaker in your electrical panel. Reset the breaker if it has tripped. If the problem persists, consult an electrician.
Inspect the power cord. Look for any signs of damage, such as cuts, fraying, or exposed wires. Never use a dehumidifier with a damaged power cord. Replace the cord (if you're comfortable doing so) or have a qualified technician replace it. A damaged cord poses a serious safety risk.

2. Review the Settings

Incorrect settings can sometimes give the illusion of the dehumidifier blowing hot air.

Check the humidity setting. Is the dehumidifier set to a very low humidity level? If so, it might be working harder and longer, generating more heat. Try increasing the target humidity level slightly to see if it makes a difference. A setting of 50-60% is usually comfortable for most homes.
Fan speed. Some dehumidifiers have multiple fan speeds. A lower fan speed might make the air coming out of the unit feel warmer. Try increasing the fan speed.
Continuous Run Mode. If your dehumidifier is set to "Continuous Run" it will operate constantly, even when the desired humidity level is reached. This can cause the unit to overheat and blow hot air. Switch it to auto mode where it shuts off when the desired humidity level is reached.

3. Inspect the Air Filter

A dirty air filter restricts airflow, causing the dehumidifier to work harder and overheat. This is one of the most common reasons for a dehumidifier blowing hot air.

Locate the air filter. The filter is usually located on the back or side of the dehumidifier. Consult your owner's manual if you're unsure where it is.
Remove the filter. Carefully remove the filter, noting its orientation so you can replace it correctly.
Inspect the filter. Is it clogged with dust, dirt, and debris?
Clean or replace the filter.
- Washable filters: Rinse the filter with warm water and mild soap. Allow it to dry completely before reinstalling.
- Disposable filters: Replace the filter with a new one of the same size and type.
Reinstall the filter. Make sure the filter is properly seated and oriented correctly.
Test the dehumidifier. Run the dehumidifier for a few hours after cleaning or replacing the filter to see if the airflow improves and the hot air issue resolves.

4. Check for Obstructions

Obstructions around the dehumidifier can also restrict airflow and cause it to overheat.

Clear the area around the dehumidifier. Make sure there is ample space around the unit for air to circulate freely. Avoid placing it in a corner or against a wall. Ideally, there should be at least 12 inches of clearance on all sides.
Check for blocked vents. Ensure that the air intake and exhaust vents on the dehumidifier are not blocked by curtains, furniture, or other objects.

5. Examine the Condenser Coils

The condenser coils are located on the back or side of the dehumidifier and are responsible for dissipating heat. If they are dirty or blocked, the dehumidifier will not be able to cool the air effectively.

Locate the condenser coils. These are usually behind a grill or panel.
Unplug the dehumidifier! Safety first!
Visually inspect the coils. Are they covered in dust, dirt, or lint?
Clean the coils. Use a vacuum cleaner with a brush attachment to gently remove any debris. You can also use a fin comb (available at most appliance stores) to straighten any bent fins. Be very careful not to damage the coils.
Reassemble the dehumidifier (if necessary).
Plug in the dehumidifier and test.

6. Inspect the Fan

The fan circulates air through the dehumidifier. If the fan is not working properly, the unit will overheat.

Listen to the fan. When the dehumidifier is running, listen to the fan. Does it sound like it's running smoothly and at the correct speed? If it sounds noisy or weak, there may be a problem.
Check for obstructions. Make sure the fan blades are not blocked by anything.
Inspect the fan blades. Are the fan blades damaged or broken? If so, you may need to replace the fan. Replacing the fan is a more complex repair and may be best left to a professional, especially if it involves electrical connections.

7. Check for Leaks

While less likely to cause hot air, a refrigerant leak can impact the dehumidifier's performance and potentially lead to overheating.

Listen for hissing sounds. If you hear a hissing sound coming from the dehumidifier, it could indicate a refrigerant leak.
Look for oily residue. Check around the compressor and coils for any signs of oily residue. This could also indicate a leak.
If you suspect a refrigerant leak: Do not attempt to repair it yourself. Refrigerant leaks require specialized equipment and expertise. Contact a qualified HVAC technician immediately.

8. Check the Compressor

The compressor is the heart of the dehumidifier's cooling system. A malfunctioning compressor can cause the unit to blow hot air.

Listen to the compressor. When the dehumidifier cycles on, listen to the compressor. It should emit a steady hum. If it's making unusual noises like clicking, rattling, or is completely silent, there could be a problem.
Feel the compressor. (Unplug the dehumidifier first!) Carefully touch the compressor. It should be warm, not excessively hot. An excessively hot compressor could indicate overheating.
Check the overload protector. The compressor has an overload protector that shuts it down if it gets too hot. If the compressor keeps shutting off and on, the overload protector may be faulty.
Compressor issues are complex and require specialized knowledge and tools. If you suspect a compressor problem, it's best to consult a qualified HVAC technician.

When to Call a Professional

While many of these troubleshooting steps are simple and can be performed by homeowners, some problems require the expertise of a qualified technician. It's time to call a professional if:

You suspect a refrigerant leak.
The compressor is malfunctioning.
The dehumidifier is still blowing hot air after you've tried all the troubleshooting steps.
You are uncomfortable working with electrical components.
The unit is still under warranty.

Preventative Maintenance Tips

Regular maintenance can help prevent problems and extend the life of your dehumidifier.

Clean or replace the air filter regularly (every 1-3 months, or more often if you have pets or allergies).
Clean the condenser coils annually.
Empty the water collection bucket regularly.
Keep the area around the dehumidifier clear of obstructions.
Store the dehumidifier properly when not in use (clean and dry, in a cool, dry place).

Conclusion

A dehumidifier blowing hot air can be a frustrating problem, but by following these troubleshooting steps, you can often diagnose and fix the issue yourself. Remember to always prioritize safety and consult a professional when necessary. With a little patience and effort, you can get your dehumidifier back to working order and enjoy a comfortable, humidity-free home.