Why Is My HVAC Filter Wet?

Have you ever gone to switch out your air filter and found it soaking wet, or at least moist? Ever wondered what happened?

Of course if you found a wet air filter, you knew to change it immediately. Leaving anything wet for a long period of time leads to mold growth. But this dampness usually indicates an ongoing problem, and you need to diagnose it fast. Why do air filters get wet, and how do we keep them dry?

 

Clogged Condensate Drain or Pan

On many HVAC units, there’s a little PVC pipe called a condensate drain or condensation line on the side. Out of this pipe, water drips. You see, this little pipe is draining off excess moisture from your A/C because condensation is a normal part of any HVAC unit. If you’re running the air conditioner, as the system draws warm air from your house to be cooled, moisture from this air condenses on these things called evaporator coils. From there, the condensed moisture drips into the drain pan and out through the drainpipe.

As you can imagine, if this drain or the drain pan become clogged, the condensed moisture won’t flow out like it’s supposed to. Instead, the water will release back into the system, and the air filter will absorb it. Condensate drains and the drain pan can become clogged by debris allowed into the system by a cheap air filter. It can also become clogged with debris from the outdoors, such as leaves and dirt. If your air filter is wet, it’s best to have a HVAC service technician out to check on the condensate line.

 

Faulty Condenser

Like a clogged condensate drain, a faulty condenser (aka compressor) can be a culprit for wet air filters. If the condenser doesn’t work, it’s not going to condense moisture from the refrigerant properly. If the refrigerant isn’t condensed properly, it won’t fully evaporate—and instead go right back into the air filter.

A condenser can fail due to many factors. One is lack of lubrication—a condenser needs oil to function properly. Another is electrical problems—if the condenser isn’t getting enough power, it won’t work. Another problem is overheating—caused by other problems within the system that raise the pressure inside the condenser. Unfortunately, if the condenser has failed, you might be up for purchasing a brand new HVAC system from Halo Heating & Cooling. It’s a very expensive repair, and if your HVAC is more than 15 years old, replacing it actually makes sense. Newer models have a lot more efficiency than older models, saving you money in the long run. You surely don’t want to find a wet air filter due to a faulty condenser, so what can you do?

 

Preventing a Wet Filter

Preventing wet air filters translates to the same thing as keeping up with routine maintenance—if you ensure proper function of your HVAC, you’ll never find a wet air filter. First thing to do in maintaining your system is simply to change the air filter often. This keeps particles from entering the HVAC system and clogging the drain or affecting the performance of the condenser. Use high quality filters in order to catch smaller particles.

Get regular maintenance by a HVAC contractor to check the function of the entire system. Getting the HVAC looked at twice a year—just before turning on the A/C in spring and before turning on the heat in fall—can prevent a slew of problems, not just wet air filters.

 

Has your air filter ever turned up wet?

If you keep changing your HVAC air filter because it’s wet, you’re just treating a symptom instead of the problem. Your wet air filter is a warning sign that something is amiss in the unit itself, so get a HVAC professional to come by and diagnose it. It’s worth it to save yourself from purchasing a new system.

Have you ever discovered a wet air filter? Was it an easy fix like a clogged condensate drain, or a mega problem like a faulty condenser? Tell us your air filter journey in a comment below!