How to Get Water Out of AC Ducts to Improve Your Home’s Air Quality

Breathe easy by checking your ducts for water

Smiling woman relaxing on a sofa at home
Photo: Westend61 / Westend61 / Getty Images
Smiling woman relaxing on a sofa at home
Photo: Westend61 / Westend61 / Getty Images
Sean Jackson
Written by Sean Jackson
Contributing Writer
Updated Oct 31, 2023
SKILL LEVEL
Easy
COMPLETION TIME
2 hours
COST
$25–$50
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What you'll need:
TOOLS
  • Dehumidifier
  • Plastic tarp
  • Scissors
  • Screwdriver
  • Ladder or step stool
SUPPLIES
  • Duct tape
  • Mastic sealant

Your HVAC system comes with ductwork that acts like the veins of your home, pushing cooler air in and drawing old, warmer air out to recondition it. As such, since you’re breathing the air from your ducts, you want them clean from all allergy irritants and water. If not, the poor air quality can cause mold growth and make you sick, especially if you suffer from allergies. This handy guide will help you learn how to get water out of AC ducts to improve your home’s air quality.

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Why Do I Need to Get Water Out of AC Ducts?

Your ductwork is an integral part of your home’s HVAC system, responsible for pushing treated air into your home while removing older air to recondition it. Along with keeping your home clean and comfortable, it’s responsible for the quality of the air you breathe. If there is any moisture present, it could lead to mold, fungi, and bacteria growth. As this grows in your ductwork, you could breathe in these particles, resulting in allergic reactions and other respiratory illnesses. 

Moisture in your AC ducts may also signify that your home is suffering from water damage, which could be a health hazard and structural issue. If you’re wondering how to stop condensation on air vents, your best bet is to follow this DIY, then consult a pro if needed.

Prepping to Get Water Out of AC Ducts

First, complete a DIY dry duct leakage test to determine where the moisture is. This will allow you to concentrate your efforts while you work. 

  1. Inspect Your Air Vents, Insulation, and Air Conditioner

    Man inspecting air vent installed in the wall
    Photo: Serenethos / Adobe Stock

    Often, when there’s moisture present in your ductwork, you’ll see it on your air vents as well. Go around to each air vent to find ones where moisture is present. 

    Another area you want to pay close attention to is your insulation. Look for signs of compression, which could indicate that water damage has been or was present. Over time, this can lower its R-Value, meaning it won’t insulate as well as intended. 

    Your air conditioner could also be the culprit. Examine the unit to see if you notice any moisture buildup, especially around the coils. On the unit located outside, you can find the condenser coil by removing the housing and inspecting for leaks. If you don’t feel comfortable doing this, you can always have an HVAC technician come out to take a look.

  2. Turn Off Humidifiers

    Air humidifier on the living room table
    Photo: Liudmila Chernetska / iStock / Getty Images Plus / Getty Images

    One of the reasons water forms in your ductwork is from a temperature and humidity imbalance in the air. Having a humidifier on might help you sleep well on dry nights, but it could also contribute to why your air vents look like they have runny noses. If you find vents having moisture in rooms with a humidifier present, turn it off to see if it helps.

  3. Find Gaps in Your Ductwork

    Rigid HVAC ductwork installed in the basement
    Photo: ungvar / Adobe Stock

    Go around your home paying close attention to its exposed ductwork. When two form together, also known as a joint, run your hand around it to test for air leaks when the blower is on. If you feel the air coming from the ductwork, there’s a leak..

  4. Seal the Leaks

    Hand applying mastic sealant on the air duct
    Photo: BanksPhotos / iStock / Getty Images Plus / Getty Images

    You can do this in several ways. One is to use a mastic sealant and then insulate all the accessible ductwork. If you don’t have the sealant, you can use a tarp and tape in the meantime. While crude, it can work in a pinch until you have a technician inspect it.

  5. Remove Moisture From Humid Rooms

    Analog hygrometer on a white background
    Photo: shutterbirdt / iStock / Getty Images Plus / Getty Images

    Some rooms of your home might be more susceptible to humidity, like an attic or bathroom. You can test the humidity in each room using a hygrometer, which measures the dry and wet bulb temperatures in the air. If it measures abnormal levels, then you know there is an issue. One way to remove humidity from a swampy room is with a dehumidifier, which removes moisture from the air.

How to Prevent Water in AC Ducts

To help prevent water buildup in your ductwork, here are some simple steps to take:

  • Repair roof leaks: You can patch a roof by replacing its flashing, or you can hire a local roofing contractor to do the work for you. 

  • Replace air filters as directed: This will keep your air cleaner and result in less particle buildup in the ducts.

  • Have your AC tuned up annually: Doing this allows the technician to clean the coils, inspect for leaks, and ensure it’s operating in peak condition. 

  • Clean your ductwork: Once every five years, have your ductwork cleaned. The average air duct cleaning cost is $380. 

  • Ensure you have proper airflow: Leaving vents closed in unused rooms creates a temperature and humidity imbalance, which can result in you finding water in your ductwork. Also, you’ll want to locate dampers if your home comes with a chimney. You might be wondering what is a damper? It’s a metal plate that allows smoke to waft through your chimney and out of your home. When you’re not using your fireplace, make sure it’s closed so cooler air cannot get in. 

  • Replace ductwork as needed: If you notice your HVAC makes loud noises or see a spike in your energy bill, you might need to replace your ductwork. A local duct installer can work with you to determine the type that’ll work well for your space. Replacing ductwork will run you between $12 to $25 per linear foot. 

DIY vs. Hiring a Pro

If you’re short on time or don’t know where the moisture in your ductwork originates, hiring an HVAC technician is a smart route to take. Service calls range from $100 to $250. However, if they notice any issues, that’ll add to the bill. 

If you don’t mind making minor repairs to see if they hold up, inspecting your ductwork won’t take more than a few hours of your time and making repairs can be as easy as cutting and applying tarp and tape.

Frequently Asked Questions

To get water out of AC vents, first identify the source of the water. Check other air vents in your home for signs of moisture. If you can’t find any, look around the room for anything that might have seeped water in like an overwatered plant or a spill. Meanwhile, if you notice more than one air vent wet in other areas of your home, it’s more than likely an issue with your insulation, roof, or air conditioner. Start by hiring an HVAC technician who can trace the source of the leak for you.

Condensation forms when warmer, outside air combines with cooler air in your ductwork. This can happen when there are leaks in your air ducts, your HVAC system has a dirty air filter, or there’s a lack of insulation around the ducts. To prevent it from happening, replace your HVAC filters as directed. Also, once every five years, hire a local air duct cleaner to clean and inspect them.

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Learn more about our contributor
Sean Jackson
Written by Sean Jackson
Contributing Writer
Sean Jackson is a freelance copywriter from Delaware, Ohio, covering real estate, home improvement, insurance, personal finance, and solar energy for CNET, Bankrate, ZDNet, and Marketwatch.
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