How to Tell If Your Home AC Compressor Is Bad: Signs and Symptoms of Failure

I’m a Sacramento guy, born and raised in Northern California, so I’m used to the big time increase in temperature each summer. The daily highs for our area in July and August reach 90 degrees on average. But what I look forward to most this time of year is an increase in something else—softball, one of my favorite sports. Unfortunately, I started this season off on the wrong foot, literally, and turned one of my ankles running out a grounder. I refused to go to the doctor until it kept getting worse. My injury wasn’t all that serious, luckily, but my doctor still gave me a lecture on how I could have avoided a good deal of suffering if I’d come for help at the first sign of trouble.

Now, as an HVAC professional who spends his summers fixing and maintaining air conditioners, I told the doc that I could relate. I tend to get calls from homeowners during these sweltering months who are panicking because their AC unit broke down. One of the most common causes for this is a failing AC compressor, a part that generally gives signs and symptoms of failure before breaking down completely. Homeowners, however, sometimes don’t call until the entire unit stops working, which is why it’s helpful to know how to tell if your home AC compressor is bad. That way, you can reach out for help before things get drastic. Taking action before the compressor has totally gone out can save you from suffering through the Sacramento heat—as well as suffering through an unexpected bill when it becomes unavoidable that an HVAC pro has to come out and fix it.

How to Easily Tell If Your Home AC Compressor Is Bad

is your home ac compressor going badNot all signs and symptoms of compressor failure are created equal. Your compressor is the part of your AC unit that transforms the refrigerant chemicals from liquid to gas and back again in a continuous cycle, generating the cool air. It’s a complex piece, and some early warning signs of trouble are far easier to spot than others, such as:

  • Sign #1 – A chattering or ticking noise: I’ve talked a lot in the past about the rumble, pop, and bang noises of a loud furnace. The thing is, a noisy air conditioner is also a sign of trouble, specifically with your compressor. Just before this component fails, it starts hard-starting, which means struggling to turn on. When you first turn on your AC, do you hear a chattering or rattling noise? If so, the electrical relay switch that starts your compressor may be wearing out. As with all electrical components, fixing this is tricky work that only an HVAC professional should tackle.
  • Sign #2 – A clicking, rumbling, or rattling noise: Similar to the noises above, a clicking sound when the AC starts could mean that the compressor motor mounts have failed and the motor that distributes cool air from within the compressor has come loose and started thrashing around inside the sealed area that houses it. Also similar to the issue above, I suggest calling a pro out to fix this because it’s dangerous to deal with loose motors if you haven’t had proper training.
  • Sign #3 – Moisture leaks: If you find puddles or moisture around any section of your HVAC system, it could mean that refrigerant is leaking out of the compressor, posing potential health risks and causing symptoms that include irritated eyes, headache, nausea, cough, and more. Also, if it continues for too long, your AC will stop working altogether because it will run dry of the chemicals it needs to generate cool air.

 Subtle Symptoms of a Bad Home AC Compressor

Loud noises and chemical leaks are easy ways to spot signs of imminent compressor failure, but there are far more nuanced ways that this component lets you know that it’s going bad. Just because these symptoms are easy to ignore, doesn’t mean you should ignore them—they’re just as likely to lead to a shutdown as their more obnoxious cousins.

  • Symptom #1 – Diminished airflow: The first, and often hardest to spot, sign that a compressor is weakening or going bad is diminished air flow from the AC vents. Like I mentioned above, the cold air is generated by the compressor, and if it’s starting to struggle, it won’t be able to generate as much air as it usually does. As a result, less air will be coming out of your vents. It’s a good idea to call a trained HVAC professional as soon as you notice this because reduced airflow doubles as a sign of clogged ductwork as well.
  • Symptom #2 – Warmer air: While some compressors will break in a way that reduces air flow, others will have a different affliction that allows them to continue distributing air. Unfortunately, this air will no longer be cool. Warm air coming out of your vents while your AC is on means that your compressor is low on refrigerant. You’ll want to call a professional to find out why.

So yes, you may have noticed that my advice can be summed up that you need to call in a trained HVAC professional if your compressor may be going bad. It’s one of the most complex components of your AC, containing chemicals as well as electrical components. The truth is that noticing these signs and symptoms of a home AC compressor going bad isn’t all that helpful if you don’t have the skills to fix them. It’s kind of like my sprained ankle. What good is trying to treat myself without any kind of formal medical training? Not much.

I know there’s a temptation once summer’s in full swing, or you see fall on the horizon, to just ride out the Sacramento heat and leave any potential problems to be dealt with when you get your end-of-season AC maintenance done. Our hot weather in Northern California has a tendency to make late May and all of June feel like four months, but there are dozens of hot days left this month, as well as into July, August, and September. Besides, a severely broken air conditioner, like a severely injured ankle, isn’t something you can ignore, especially if recognizing any of these signs and symptoms means you can find a fix before total failure sets in.

Fix your struggling AC compressor now before it leads to total failure of your air conditioner. The trained professionals at Bell Brothers can help you avoid a summer cooling catastrophe.

Image courtesy Unsplash user Gus Ruballo