Hey Folks—Tony Here 👋
Look, I’ve worked on more coils than I can count, and I can tell you this: when an evaporator coil starts to fail, it doesn’t go out quietly. It throws out warning signs like a bad alternator. The problem is, a lotta homeowners don’t notice ‘em until their system’s wheezing like a smoker in July.
So today, I’m gonna walk you through five dead giveaways that your evaporator coil needs some serious TLC—or maybe even a full-on replacement. We’ll talk symptoms, causes, and what to do about it, all in plain English. Let’s get to it. 🔧
1. Your HVAC System Is Blowing Warm Air (When It Shouldn’t Be) 🌡️
One of the biggest red flags? Your system’s supposed to be cooling—but your vents are kicking out air that feels more like spring break in Florida.
This usually means your evaporator coil isn’t absorbing heat like it’s supposed to. Why? Could be low refrigerant, corrosion, or a frozen coil (yep, that’s a thing—we’ll get to it).
Here’s a solid resource from Energy.gov on air conditioner issues that breaks this down more.
What to do:
First, check your thermostat settings and replace your air filter. Still no luck? Time to call in a tech to check refrigerant levels or inspect the coil for damage.
2. Strange Noises or Hissing Sounds from the Indoor Unit 👂
A healthy coil is pretty quiet—it just sits there, quietly doing its job. But when things go south, you might start hearing hissing (hello refrigerant leak) or bubbling sounds.
A refrigerant leak is no joke. Not only can it kill your system’s performance, but it’s also a hazard to your health and the environment.
What to do:
Don’t try to seal leaks with DIY foam or tape. Leaks need to be professionally repaired, and your refrigerant levels must be rebalanced. If the coil’s too far gone, a replacement might be cheaper long-term.
3. Ice Buildup on the Coil or Around the Indoor Unit ❄️
Here’s one that always surprises people—yes, your AC can freeze in the summer. When the evaporator coil can’t get enough airflow (thanks to clogged filters, duct issues, or a malfunctioning blower), moisture on the coil freezes.
Eventually, that ice blocks heat transfer and your system turns into a useless block of frost.
What to do:
Shut off the system to let it thaw. Change the air filter. If the problem keeps coming back, your coil may be the problem—either dirty, damaged, or leaking.
Here’s a helpful walkthrough from HVAC School on diagnosing frozen coils like a pro.
4. Funky Odors When the AC Kicks On 🤢
If you’re getting moldy, musty, or even sweet chemical smells from your vents, don’t ignore it.
A compromised coil can grow mold if condensation doesn’t drain right. Or worse—it could be a refrigerant leak, which smells sort of like ether or sweet chemicals. Neither one is good for you or your indoor air quality.
What to do:
Schedule a cleaning if the coil is just dirty or moldy. But if it’s a leak? That’s a serious issue. Check this guide on indoor air quality threats from the EPA to understand the health impact.
5. Your Energy Bills Are Creeping Up for No Clear Reason 💸
If your HVAC hasn’t changed and your thermostat settings are the same—but your bills are climbing—it could be a worn-out coil.
When coils get grimy or leaky, your system has to work harder to cool your space. That means more run time, more stress on your compressor, and more money flying out of your wallet.
What to do:
Have your system inspected. If the coil’s still under warranty, it might be worth replacing. (FYI: Goodman coils tend to come with decent warranties—check your paperwork!)
So, Should You Repair or Replace the Coil? 🤔
Good question. If the coil’s relatively new and the damage is minor—maybe a small leak or clog—you might get away with a repair.
But if it’s corroded, leaking badly, or out of warranty, replacing it is usually the smarter long-term move. Especially since refrigerants like R-22 are being phased out, and older coils aren’t always compatible with the new stuff like R-32.
Here’s a good read from HVAC.com that breaks down replacement costs and considerations.
Tony’s Final Take 🧢
I always say this: your HVAC system talks to you—you just gotta know how to listen. If your home’s suddenly too warm, too loud, or too expensive to keep cool, chances are your evaporator coil is part of the problem.
Catch the warning signs early, and you can avoid an emergency call on the hottest day of the year. Trust me—those never come cheap.
Need a new coil? You can browse quality evaporator coils right here at The Furnace Outlet. We carry top-rated, fully warrantied models for systems big and small.
Need more evaporator coil cleaning tips? Visit: Coil Gunk Got You Down?
Until next time, keep cool—and don’t let your coil leave you out in the heat.
—Tony the Trusted Tech🔧
