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Causes of a Leaking Air Conditioner

In order to prevent damage to your home, the most important thing to do when dealing with a leaking air conditioner is to turn it off as soon as possible. This way, you can stop any damage from occurring while you or someone providing you air conditioner service in Chicago, Illinois, is fixing the problem.

The next most important thing to do, of course, is to figure out what’s causing the leak so it can be fixed as quickly as possible. In order to know what’s causing the leak and find the right air conditioner service in Chicago, Illinois, you’ll need to know a little bit about how an AC unit works. Here is some more information from our team at Deljo Heating, Cooling & Plumbing.

Where Moisture Comes from in an AC Unit

Even more advanced AC units are manufactured in similar ways to old ones, so it’s safe to say that—regardless of age—AC units generally have an evaporator coil, a drain pan, and a condensate drain line. Each one of these components may be the source of your leak, but our team will be able to pinpoint the source for you.

The evaporator coil cools down hot air as that air blows over the coil itself. Just as a can of pop will “sweat” with droplets of water running down the can on a hot day, so too will your AC’s evaporator coil. This in itself is not an issue because when everything is working correctly, that moisture will be captured by the drain pan and sent down the condensate drain line. Knowing this information, we can dive into the causes of a leaking air conditioner

1. Low Airflow

Often times, if the air filter on your AC unit is dirty, this will restrict the flow of hot air over the evaporator coil. Because there’s no warm air to cool it down, the evaporator coil freezes and as it melts, it produces more water than the drain pan has capacity for.

2. Blocked Drain Line

In the event the condensate line is blocked, which is often the result of dirt, mold, or dust clogging the line, water will leak out. When this happens, you’ll need professional air conditioner service in Chicago, Illinois, unless you can remove the blockage yourself.

3. An Old Drain Pan

A simple, but quite common problem is that the AC’s drain pan is damaged due to age. Due to this, water from the evaporator coil drips out with no pan to catch it. This one is a simple fix and all you’ll need is a new drain pan.

Contact Deljo Heating, Cooling & Plumbing Today

Fixing a leaking air conditioner on your own can be difficult and complicated. It’s best to leave this task to our skilled team. If you’re in need of our services due to a malfunctioning air conditioner, we are happy to help. Call us at 773-829-4295 to get started.

Client Testimonials

Read the opinions of our satisfied customers.

5 stars

This was my first time as a Deljo customer, and I was very pleased. My technician, Giovanni, was very thorough and diligent. He serviced my furnace and identified a faulty sensor that was causing the unit to shut itself down. Deljo ordered the part, and Giovanni replaced it a few days later. Overall, the team at Deljo was great. The dispatcher kept me informed about Giovanni’s arrival time, and the supervisor assisted Giovanni when he was diagnosing the problem with the furnace. I highly recommend Deljo.

Paul D. 10/15/2026

5 stars

I’ve used Deljo for over 10 years now and they always do a good job. Izzy was the technician for this visit and he did an excellent job with my winter maintenance on my multiple units in the household. He also addressed an issue while cleaning the furnace blower wheel. His communication was clear and concise with what he planned to do to address the issue quickly. He was confident and I had 0 concerns or questions. Great job Izzy!

Jeff S. 10/14/2026

5 stars

Paul was great! Arrived on time and completed maintenance on my humidifier, tankless water heater, and two furnaces. All work was performed under my Gold Star maintenance program, so all maintenance charges were covered. Paul did provide a few proposals for additional services on furnace & tankless water heater, but those were emailed to me for further consideration. Paul was friendly, knowledgeable, and answered all my questions.

Jack N. 10/12/2026

5 stars

Gabe did an excellent job with our annual service visit. He arrived in the early part of our service window, was friendly and knowledgeable, and got the work done in a very reasonable amount of time. I have great confidence in Deljo, and am a long-time customer.

Ruth C. 10/9/2026

5 stars

I’ve been using Deljo for 20 years for HVAC but now venture into enlisting their plumbing services. Bashar was very courteous, efficient & informative, and I’d definitely request him again for the next plumbing job. Great experience!

Christopher R. 10/2/2026

5 stars

Working with Deljo is always a good experience, and today’s appointment with Izzy was no different. He was able to come early which actually worked better with our schedules, but called me ahead of time to make sure that was okay. He was friendly and knowledgeable when he explained the work he had done during his visit and our options for fixes. He was also able to schedule a quote appointment for us while he was still here. We would highly recommend working with Izzy and the Deljo team!

Lauren H.  9/25/2026

5 stars

Drew performed the seasonal maintenance on my AC. It needed some repairs and updates and he was able to fix everything at the same appointment. He also noticed issues with the hot water heater and we were able to get ahead of that, as well.

Emily W. 9/11/2026

5 stars

I would leave six out of five stars if I could! My technician Jorge went above and beyond on his service. There was buildup in the rental property’s toilet from the previous tenant. One maintenance person did a surface level job of cleaning but did not fully remove the obstruction. Jorge went above and beyond and came to a solution and even explained the perpetual problems older toilet models can cause. Moving forward with this insight, I can perform my own upkeep the previous tenant did not. Thank you kindly!

Kayla K.  9/15/2026

5 stars

We just had our new boiler installed by Jonathan and Carlos. First rate work! They arrived on time, removed the old boiler, installed the new unit, and explained the features. Both guys were pleasant. Bring on the cold this winter! We are ready thanks to the team from Deljo.

Edward B.  6/26/2026

5 stars

Deljo’s heating and cooling team was awesome to work with. As a first-time homeowner, I really appreciated how clearly they explained everything and answered all my questions. From the quote to the install and follow-up, the service was top-notch. Highly recommend!

Lindsey A. Chicago, IL

5 stars

Matt did an amazing job. He serviced our home and our rental property. He gave us options to help our systems run more efficiently. He also told us about Deljo’s new plumbing inspection which was very affordable. He is great!

Jordan R. Chicago, IL

5 stars

We had a problem with our Humidifier and called Deljo. Jesus came out to help and was amazing. He was extremely knowledgeable, detail oriented, and super courteous. Amazing customer experience!

Jeff C. Chicago, IL

5 stars

Jordan and Jesus were extremely helpful and knowledgeable! We would 100% work with them and have them back. They were both very professional and efficiently fixed our heating system.

Emily L. Chicago, IL

5 stars

Shout out to Ernesto for coming out and servicing our furnace and air con. Deljo provides a great service and glad to trust them with our HVAC for our small business.

Lauren H. Chicago, IL

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