Troubleshooting Excessive Condensation from Air Conditioning -
Problems and Repair Tips

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Find the reasons for the excessive condensation from air conditioning and how to repair problems successfully.

From the clogged drain line to frozen coils, there are many reasons why your air conditioner or a heat pump is dripping condensate.

Here, we will explain the most common causes.

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See is condensation dangerous for people and what problems condensate can create.

When seeing water dripping down an AC and the puddle of water on the floor, many people, including me, are worried. And that’s normal. The first thing we imagine is a flooded basement and property damage. Or a broken air conditioner and expensive repairs.

While your air conditioner is designed to cool and remove moisture from the air, it can also generate some condensation, but it can be a problem if there is an excessive amount.

Since there are two sections of the AC system, indoor and outdoor, condensation on the indoor unit could be damaging and would need your immediate attention.

Problem: My AC is leaking/dripping water. How much condensation from the AC is too much?

If you see your air conditioner or heat pump leaking water, the first thing you should do is to figure out the location of the leak and explore how big the problem is.

Check out if your AC is just "sweating," dripping, or if it is leaking in an excessive amount. It is normal to see an AC dripping water occasionally during hot and humid days, especially when it is working hard.

At the first sign of a problem, especially when there is excessive condensation, get it checked. If you leave it unattended, you could end up with property damage and unit failure, mold, and algae growth followed by health issues.

So, what is condensation?

Condensation is the process where water vapor turns into liquid.

You could often see it on your windows during cold days when warm indoor air comes in contact with a cold surface. Another good example is a “sweaty pipeline,” which occurs when cold water runs  the pipes surrounded by the warm and humid air. Or when you have a cold glass of water, or beer, on a hot and humid day.

Signs of too much moisture in your house

  • High humidity
  • Musty smell
  • Condensation
  • Dripping water
  • Water damages
  • Signs of mold and mildew
  • Low performing AC/heat pump

What causes condensation on air conditioners?

Clogged condensate drain line and draining issues

As the moisture from the air condenses on the AC coils, it would generally drain away utilizing the drain system and remove the condensate into the drain pan or away using the pump.

The problem here is that the drain line sometimes gets clogged preventing normal condensate transfer to the proper and safe area, resulting in water blockage and eventually spill out of the pan.

Also, the drain pan can get blocked, resulting in the overflow, or the condensate pump could stop working, causing water accumulation and leak.

Repair tips

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  1. Inspect and clean the drain pan and its pipes if you see any standing water or water is not draining.
  2. Use the wire brush, shop-vac, or a special pump to force it out. You can also put some bleach from time to time to clean the pipes and prevent mold at the same time.
  3. Always consult the manufacturer's manual about the installation as some types require mounting units on the flat surface while with the window-type, for example, tilted upwards, so the water drains outside.

Broken condensate pump

If the condensate pump is broken and failing to pump the water outside the AC, the water will accumulate and start leaking from the unit.

Repair tips

Contact your local HVAC technician to repair or replace a broken condensate pump.

Drain pan problems

A drain pan or condensate pan is designed to collect dripping water when the condensation occurs on the coils. The pan is located directly below the unit. It can also use the drain line to transfer the condensate to a safe place. Or, it can end in the floor drain.

Since the condensate brings debris and dirt into the pan, including mold and algae growth, the contaminants block the drain line over time. With the blocked line, the condensation buildup cannot find its way to escape the pan and starts overflowing.

The leak can also occur if the pan is rusty or broken, also improperly installed, or undersized.

Repair tips

Check to see if the drain pan is in good working condition and the drain line is not blocked. Maintain it regularly to clean all dirt and debris. Proper and on-time cleaning is the best way to prevent clogging.

Also, if the pan is cracked, you can fix it with the proper sealant, while rusty drain pans should be replaced.

Dirty air filter and restricted airflow

Every AC uses air filters to clear the conditioned air from dirt and dust particles (including allergens), thus improving your indoor air quality. Due to heavy dirt accumulation, dirty air filters would block or reduce the normal airflow, decrease performance and efficiency, or damage the compressor. While working hard, the evaporator coils will freeze and then melt, resulting in leaks.

Repair tips

As with all HVAC systems, proper maintenance is the key to efficient AC operation, especially during the peak season – summer.

The solution for a dirty air filter is simple, and you can DIY.

Make sure to inspect, clean, or replace filters when needed and according to the manufacturer’s instructions. Filters can be found in most hardware stores or online; they are not expensive and are easy to replace.

Low refrigerant charge

Every AC needs some sort of refrigerant to run through the system and transfer the heat. If, for some reason, there is not enough refrigerant, the pressure drops, and the evaporator coil becomes very cold, resulting in ice buildup. Over time the ice formation starts to melt, causing water to drip from the unit. 

Repair tips

It is recommended to contact a technician to deal with this kind of problem - professionally.

Excessive condensation due to vent issues

As we know, most central heating and air conditioning systems utilize ducts to transfer heated or cooled air. These ducts are made of sheet metal and are usually insulated to prevent unwanted heat transfer between the conditioned air and surrounding.

While the AC is running and removing the heat from indoors during the summer, the cold air goes through the vents to the outside atmosphere. If there is no insulation, is missing or damaged, the warm and humid air can get into the ducts and cause condensation when it gets in contact with the cold duct walls.

Condensation on the surface of your AC ducts is also known as ductwork sweating. 

Repair tips

One of the solutions for this problem is to check, add or repair any missing insulation. Or, instead of metal ducts, use fiberglass or any other non-metallic material.

Clean the ducts regularly to allow proper airflow and use a dehumidifier if needed to reduce the humidity level.

In addition, you might find water dripping through the ducts when the ice on the frozen coils starts melting. Check if your defrosting mode is still operational and efficient, and if not, contact your service technician.

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Is condensation safe, or not?

As we know, condensation in the form of water comes from the surrounding air, but it might contain impurities that are not all good for your health. That is why the water collected from an air conditioner should not be used for consumption/drink - simply because it is not safe.

This water is actually distilled water, and it lacks necessary elements making it unsafe for human consumption and corrosive to metals.

Also, if your AC and surrounding are not chemically treated, condensate water can be used for watering plants but won’t give plants enough nutrients.

Problems condensation can cause

There is a high possibility that excessive condensation in air conditioning can cause water damages to your home. This often happens to your indoor unit, especially if it is not protected.

Another problem with excessive water buildup and leaks, and due to high humidity levels, are mold and mildew growth.

High humidity can also make your air conditioner work harder than before, resulting in a high-stress environment and premature element failure.


Excessive condensation from air conditioning occurs due to frozen coils, clogged filters, airflow problems, and similar issues. It often leads to element failures such as a compressor, leaks, and property damage, and that is something you want to avoid. It makes sense to check out the possible causes as soon as possible. Still, it is recommended to contact a professional to deal with your air conditioner or a heat pump - professionally.

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