What Causes Water To Build Up in Ductwork?

Water in your HVAC system can be quite problematic. Not only does it cause foul odors, but it can also be a health hazard. The best way to prevent these unwanted symptoms is to know what causes moisture to puddle in the ductwork throughout your home.

Water builds up in ductwork due to leaky HVAC pipes, excessive humidity in the building, and roof leaks. These can be treated by using dehumidifiers and sealing the leaks. However, it’s essential to remove moisture, mold, and mildew from the ductwork to prevent them from spreading.

Throughout this post, we’ll explain why there’s moisture in your ductwork, what you can do about it, and why it should be removed and treated as quickly as possible.

Most Common Reasons Water Collects in Your Ductwork

There’s water in your ductwork because there’s a leak somewhere in the plumbing, HVAC system, or roof. Water leaks can lead to moisture throughout the building, hindering the ductwork’s ability to heat or cool the space. Another issue is when there’s a lot of moisture dripping from condenser coils.

In fact, Jenkins Restorations reports that the vast majority of water in ductwork is caused by leaks in the HVAC system or roof. Rainy days can tear through the room, drip through the attic, and puddle in the pipes.

It can also happen if you have whole-house humidifiers or multiple portable humidifiers in your home. Use a hygrometer to manage the humidity. Your home’s humidity should range between 35% to 45% to prevent the ducts from getting too wet or moldy.

Read: Residential And Commercial Ductwork – What Are The Differences?

How To Get Rid of Water in Ducts?

To get rid of water in ducts, follow these steps:

  1. Dry your air ducts with a vacuum system. It’s important to remove the moisture before sealing the ductwork. HVAC vacuums are the most efficient tools when it comes to removing excess moisture from the ducts. The rest of the water will be removed and dried when you turn on the ventilation system.
  2. Use duct tape to seal the ductwork around your home. TapePlus Aluminum Foil Tape is the go-to duct tape that seals all kinds of ductwork. This tape is 2” x 210’ (5.08 cm x 64 m), but it also comes in many other sizes and thicknesses. It can withstand temperatures between -4°F to 250°F (-20 to 121°C), making it perfect for any HVAC setup.
  3. Monitor and adjust the ambient humidity in the building. All Dry US explains that you need to control the humidity in your home to prevent the ductwork from getting too wet. Since moisture flows into the ducts, we suggest putting dehumidifiers close to the air inlets. You can also choose a whole-house dehumidifier.
  4. Check the area around the wet ductwork for insulation gaps and condensation buildup. Many types of insulation get matted and thin. This process makes them much more susceptible to thermal bridges, increasing the chances of condensation forming in the attic, walls, crawl spaces, and ductwork.
  5. Inspect the condenser coils around your air conditioning unit. These coils are used to reduce the temperature in your home. However, they can freeze if there’s too much moisture and they get too cold. Once this happens, the excess moisture melts and spreads throughout the HVAC pipes.
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02/18/2024 01:21 am GMT

Read: How To Locate HVAC Dampers In Ductwork?

What Happens if Water Gets in Ductwork? 

If water gets in ductwork, it can cause mold growth, reduced airflow, and limited temperature control. Additionally, moisture can weaken the HVAC ducts, increasing the likelihood of cracks and dents. These problems all become exponentially more expensive if they’re not treated as soon as possible.

Here’s an in-depth look at each of these issues:

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  • Water in an HVAC system is one of the main causes of mold in air ducts. Not only does it smell gross, but it can also cause respiratory problems, headaches, fatigue, and more. Mold in HVAC systems leads to cold-like symptoms, leading you to believe you might’ve caught a virus.
  • According to Structure Tech, water in ductwork can narrow the pipes and reduce airflow. This makes the house feel musty and stale. The only way to treat this problem is to open the windows, which means you can’t use your HVAC system without wasting gas or electricity.
  • It’s very difficult to control the temperature in a building when there’s a lot of moisture in the ductwork. You’ll have to pay increased utility bills to maintain the desired temperature. There’s no way to get the temperature out of the ducts in a decent timeframe, which makes harsh winters and brutal summers much harder to handle.
  • Cracks, dents, and stains can form if there’s too much water in the HVAC system. The weight of the water puts a lot of pressure and strain on the duct joints. After this process develops for a few weeks or months, you’ll notice leaks. It can also cause dents, which are often misdiagnosed as suction dents.

A little bit of water in a building’s ductwork isn’t uncommon, especially if the building is old. However, it must be handled if it forms mold, mildew, and clogs. It also needs to be dealt with if the air can’t properly flow through the HVAC pipes, drastically limiting your ability to ventilate the structure.

Read: Does Ductwork Need To Be Sealed?

How to Know if There’s Moisture in Your HVAC Ducts?

To know if there’s moisture in your HVAC ducts, look for these signs:

  • Musty smells throughout the building can indicate moisture in the ductwork. Mold and mildew have very distinct odors that are nearly impossible to miss. If your home smells earthy, stale, and humid, there’s likely mold in the ducts. This is increasingly likely if it smells that way near all of the vents.
  • Mold or mildew growth around the vents often shows there’s water in the HVAC system. It grows on the interior fins. Open the vents all the way and look at both sides of the fins on each vent for signs of mold growth. They often start as speckled black or green dots that look like spray paint.
  • Listen for gurgling noises when you turn on the ventilation system. This noise occurs when the air moves quickly through the ducts, rippling the stagnant water. It’s much more common near the flat portions of the pipes. Listen to each of the vents to find out if there’s water in the system.
  • Look for cracks and dripping pipes. HVAC cracks often form from rust and corrosion, which means there’s moisture in the area. These cracks can be repaired when they’re small and new. That said, it’s much more challenging to repair large HVAC cracks because they quickly expand.
  • Check the ceiling for water spots. Water spots warp the paint under damaged HVAC pipes. They’re often some of the first signs people notice when there’s a leak. Unless you see mold or smell mildew, you likely won’t notice there’s water in your HVAC system until water spots form on the ceilings and walls near the pipes.

Read: Should Ductwork Be Insulated?

Final Thoughts

While water in your home’s ductwork can be damaging and dangerous, it can be remedied to prevent it from worsening. Testing your home’s humidity and managing small leaks can make a big difference. Additionally, it’s a good idea to improve and monitor your home’s insulation.