How to Tell If Your HVAC Is Leaking Refrigerant

Got your AC running, but still feeling uncomfortable inside? That’s a sure sign that something isn’t right with your equipment. You might start asking how to tell if your HVAC unit is leaking refrigerant, since that can mess with your system’s efficiency right away. We can help!

This guide walks you through the most common warning signs of a refrigerant leak, what they actually mean, and when it makes more financial sense to repair vs replace your system.

 

7 Signs Your HVAC Is Leaking Refrigerant: Quick Reference

Refrigerant leaks don't announce themselves loudly — they usually show up as a slow, accumulating set of symptoms that are easy to attribute to other causes. If you are noticing two or more of the signs below, it is time to have a licensed HVAC technician inspect your system. Refrigerant levels can only be checked and recharged by a certified professional — it is not a DIY repair.

 

 

What Does Refrigerant Actually Do in Your HVAC System?

Refrigerant cycles through the indoor coil (also called the evaporator coil) of your HVAC system and the outdoor unit. It’s both a liquid and a gas, and it works in a closed loop to move heat out of your home and then bring in cold air.

Your system needs enough refrigerant in order to function properly and keep cooling. So whenever you notice a lower cooling capacity or inconsistent temperatures, it might be due to refrigerant loss, not just normal wear and tear.

How Do You Tell If Your AC Has a Refrigerant Leak?

Since an HVAC unit is a sealed system, it shouldn’t ever lose refrigerant while it’s running. So if it turns out that the levels are low, that almost always points to a refrigerant leak, which means you’ll need a repair. It’s not something that’s going to fix itself.

You can look for a handful of signs to help determine whether you have an AC refrigerant leak or another problem going on. Typically, homeowners notice performance issues first, and then realize that there are other physical signs around the system.

For example, your AC unit may start putting out warm air instead of cold air, even though it’s running constantly. Then you might take a look and see ice forming on the evaporator coil, indoor unit, or along the refrigerant lines. This happens because having low refrigerant will upset the pressure inside your system, which causes the coils to get too cold. At the same time, your energy bills could be climbing as your HVAC unit struggles to maintain temperature.

A faint hissing sound near the outdoor unit can also suggest that you have refrigerant escaping from a small crack or loose connection. If you’re noticing more than one of these symptoms (e.g., poor cooling, ice buildup, higher energy bills, or unusual sounds), it’s usually a strong indication that you have refrigerant leaking. At that point, the next step would be to have an HVAC technician come out for a proper diagnosis. They can use a leak detector or pressure test to figure out where exactly the leak is coming from, and then help you run the numbers on whether it’s a manageable repair, or if it might be time to consider a full system replacement.

Why Is My AC Running But Not Cooling the House?

One of the most common signs of a refrigerant leak is when you’re having your AC unit run constantly, but it’s only producing warm air. The problem with low refrigerant is that your system isn’t able to absorb enough heat indoors to push it outside. This leads to poor cooling and longer run times. Low refrigerant can also mean you’re just getting a weaker airflow from the vents, so even though the system is technically working, it’s still not strong enough to keep the house cool.

Why Is There Ice on My AC Unit in the Middle of Summer?

Ice buildup is a major red flag for leaking refrigerant. When refrigerant drops too low in the HVAC system, the pressure inside the evaporator coil decreases. This causes the coils to get too cold, and sometimes they freeze over, even in summer.

You might be seeing ice on the indoor unit, outdoor unit, or even along the refrigerant lines. Any of these places can indicate a problem. If you notice this, turn the system off and let it thaw. Running HVAC equipment when it has ice can put extra wear on the compressor, which might then require you to replace the part. That’s one of the most expensive repairs you can face, so be sure to keep your system safe until you can get a professional to fix the issue.

Where Do Refrigerant Leaks Most Commonly Occur?

Most refrigerant leaks happen in the copper lines, copper tubing, and coil seams in the evaporator coil or condenser. You might get small cracks because of corrosion, or just general wear over time from vibration that eventually turns into larger leaks. Technicians can use tools like a leak detector or a UV light to pinpoint the exact spot. Then they can make an effective repair and do a refrigerant recharge to get your system back in good working order.

How Long Do HVAC Refrigerant Coils Typically Last?

Your system’s coils will typically last 10–15 years with regular maintenance. That being said, once a leak pops up, it can be difficult to make a repair. In a lot of cases, replacing the coil, or even opting for full system replacement, is actually the more practical solution, especially if your system is older.

How Much Does It Cost to Detect and Repair a Refrigerant Leak?

If you suspect a refrigerant leak, you’ll need to call on an HVAC professional to officially diagnose the issue. They can use a pressure test and specialized tools to get to the source of the problem. Depending on your area, this alone could cost a few hundred dollars. But the repair work itself can vary wildly. The location of the leak might be easy to access. On the other hand, you might have to move forward with replacing something like the entire evaporator coil, which can get expensive.

On the bright side, you’ll be in a better position to save when you know where to shop. At Surplus City, we stock discounted HVAC parts and equipment, so you’re able to save on every project. We sell to both contractors and homeowners. If you’re looking for affordable repair parts or even brand-new systems, we’re your one-stop shop!

What Is the $5,000 Rule for AC, and When Does Replacement Make More Sense?

The $5,000 rule is a simple formula for HVAC equipment that can help you decide between making a repair or going with a full system replacement. You just multiply the age of your HVAC unit by the estimated repair cost. If the total is higher than $5,000, investing in a replacement is often the smarter financial move.

For example, if your 12-year-old system needs a $600 coil repair, you’re looking at $7,200, which is well past the threshold of the $5,000 rule. At that point, upgrading to a new system can help you avoid repeat issues, all while improving your energy efficiency. Once again, you can count on Surplus City to help! We source HVAC equipment from all of today’s top manufacturers and offer big discounts on systems of all sizes. We make it more affordable to get the heating and cooling solutions that will keep you comfortable.

Where Can You Find Replacement HVAC Equipment Without Paying Full Price?

If your system has a larger leak or needs major repairs like coil or compressor replacement, opting for an upgrade may be the better long-term decision.

At Surplus City, we source brand-new, never-installed equipment directly from trusted HVAC manufacturers like Carrier, Trane, Lennox, and American Standard at significantly reduced prices. We then sell to homeowners, property managers, and contractors alike. It’s all about helping you avoid paying full retail price!

You can count on us for great deals year-round. If you’re trying to figure out how to tell if your HVAC unit is leaking refrigerant, the sooner you can identify the signs, the easier it is to make a smart decision about your next step. Whether that means a repair or a replacement, we can help you get what you need to tackle the job and save.