If you’re reading this, chances are you’re frustrated with your dehumidifier. I’ve been there—walking into my basement after a rainy week, expecting that nice, dry air, only to find that my trusty machine wasn’t doing its job. Troubleshooting dehumidifiers isn’t always straightforward, but after years of using one in my basement, I’ve learned how to diagnose the most common problems and get them working again.
This isn’t just a list of fixes—it’s a step-by-step guide based on my personal experience. Whether your dehumidifier isn’t collecting water, smells odd, or just refuses to turn on, these steps will help you figure out what’s going wrong and what you can do about it.
Step 1: Start with the Basics – Power and Placement
The first time my dehumidifier stopped working, I panicked. But then I realized the problem was embarrassingly simple—it wasn’t plugged in properly.
Before you assume something is seriously wrong, check the power source. Plug the dehumidifier into a dedicated outlet, and if that doesn’t work, try another device in the same outlet to make sure it’s not the power supply. I once discovered that my basement outlet had tripped, and resetting the breaker instantly solved the problem.
Placement matters, too. Dehumidifiers need airflow. If it’s shoved into a corner or surrounded by boxes, it won’t work properly. I learned to keep at least 12 inches of space around mine so the intake and exhaust vents can breathe.
Step 2: Check the Humidity Settings
If your dehumidifier runs but doesn’t seem to be collecting water, your settings might be the issue.
Most modern units have a humidistat—a built-in sensor that turns the machine on and off based on your target humidity. I once set mine to 60% by accident, thinking that was low enough, but basements need to be around 45–50% for noticeable results.
If your unit isn’t turning on often, try lowering the target humidity. On the flip side, if it’s running nonstop but never hits the target, you may have a bigger issue (like a faulty sensor or a leaky basement letting in more moisture than the dehumidifier can handle).
Step 3: Clean the Filter and Coils
One of the most common problems I’ve faced? A clogged air filter.
After a few months of use, my dehumidifier’s filter was coated in dust. It was still running, but barely pulling any moisture from the air. Once I removed and cleaned the filter (most can be rinsed with water), the difference was immediate.
Don’t forget the coils, either. Dirty coils can make your dehumidifier freeze up. I once found a layer of frost on mine because the airflow was blocked. A soft brush or vacuum can help clean off dust buildup, but always unplug the unit before you start cleaning.
Step 4: Look for Frost or Ice Buildup
Speaking of frost, frozen coils are another issue I’ve run into. This usually happens when the basement gets too cold—most dehumidifiers aren’t designed to work well below 60°F (15°C).
When I noticed ice on the coils, I turned off the machine, let it defrost completely, and moved it to a slightly warmer spot. Some models have a defrost mode that helps with this problem, but if yours doesn’t, running it in very cold conditions will keep causing issues.
Step 5: Check the Water Tank and Drainage
One time, my dehumidifier simply shut off without warning. The culprit? A full water tank.
If your unit has an indicator light, it’ll usually tell you when the tank is full. But if you’re using continuous drainage (like I do), check that the hose is properly attached and not kinked. I’ve had my hose come loose more than once, which caused the unit to stop running.
For models with a pump, make sure it’s working properly. If the pump fails, water can back up and trigger the auto-shutoff.
Step 6: Listen for Strange Noises or Smells
Over time, I’ve learned that unusual sounds or smells are my dehumidifier’s way of asking for help.
If you hear grinding, rattling, or clicking, it could mean loose parts or a failing fan. A quick inspection (and tightening of screws) often helps.
A musty or burning smell is more serious. I once ignored a faint burning odor, and it turned out the fan motor was overheating. If you notice this, unplug the unit immediately and consider getting it serviced.
Step 7: Compare Your Dehumidifier’s Capacity to Your Basement’s Needs
One problem I ran into early on? My dehumidifier was too small for my basement.
If you’re using a 30-pint dehumidifier in a 1,000-square-foot basement, don’t be surprised if it struggles. I eventually upgraded to a 70-pint model (with continuous drainage), and the difference was night and day.
When troubleshooting dehumidifiers, always consider whether your unit is powerful enough for the space it’s working in.
Step 8: When to Call for Professional Help
Sometimes, no amount of DIY fixes will solve the problem.
If your compressor fails, the refrigerant leaks, or the electronics malfunction, it’s usually time to call in a professional—or replace the unit altogether. I had to replace my first dehumidifier after six years of heavy use because the repair cost was higher than buying a new one.
My Takeaway: Don’t Ignore the Small Signs
If I’ve learned anything from years of using a basement dehumidifier, it’s this: fix small problems early.
When my dehumidifier wasn’t collecting water, I didn’t wait weeks to figure it out. I checked the tank, cleaned the filter, and adjusted the settings. When it froze up, I learned that my basement temperature was part of the problem.
Troubleshooting dehumidifiers isn’t as intimidating as it seems once you understand how they work. Most issues are simple—dirty filters, full tanks, or incorrect settings—and easy to fix on your own.
Final Thoughts
Dehumidifiers are essential for keeping a basement dry, fresh, and mold-free. But they’re not perfect, and they need regular attention to keep running smoothly.
By following these steps—checking power, cleaning filters, adjusting settings, and paying attention to strange sounds or smells—you can solve most common problems yourself. And if all else fails, don’t hesitate to get a professional opinion.
Over time, you’ll get to know your dehumidifier well enough that troubleshooting becomes second nature. Mine has been running strong for years now, and I’m confident yours can, too, with the right care and maintenance.