Why Is My Air Conditioning Making A Hissing Sound?
Kevin Allen
Co-Founder & Service Lead

It’s a sun-shiny day here in Ventura County. It’s a great time to take the kiddos to the park, go for a hike with your spouse, or just catch some rays out in the back yard and work on your summertime tan.We’re quickly approaching summertime, and the heat is on! So turn on the air conditioning! After a day at the beach, a walk outside, or just hanging outside by the pool, you’ll want a comfortably cool home to retreat to. What could possibly go wrong?The summertime heat is no match for an air conditioner in perfect working order… except when it starts to behave strangely. Is that a hissing you just heard? That can’t be good…So what do you do when you notice your air conditioner is making a hissing noise? And what’s going on in there? Let’s dive into the why and what to do when your air conditioner starts hissing suddenly.
Don’t Try to Fix it Yourself!
First things first: If you hear a hissing sound coming from your air conditioning unit, it's best to turn it off and give us a call ASAP to inspect and repair your air conditioner system.Whenever you notice something concerning with your HVAC system, it’s important to get the assistance of a professional HVAC technician. And we’re the team for the job! We don’t recommend DIY’s or trying to figure out the cause of the problem on your own. This is for the safety of yourself and your family, we also wouldn’t want you to accidentally make things worse. So put down the screwdriver and let us give you a hand!If your air conditioning unit is making a hissing sound, it may be a symptom of a bigger issue. And with any issue involving your HVAC system, you'll want a Mom-Approved technician on the job. Now let’s get into some common causes of why your air conditioning is making a hissing sound.
Common Causes of Hissing Sounds in an Air Conditioner
There’s a few common causes of hissing sounds coming from your air conditioner, some serious, some not so serious. Regardless, there’s really no way of knowing without getting a Mom-Approved [company_name] technician on the job to solve the mystery and save the day. Still, you want to know what's going on! If your air conditioner is hissing, it could be due to one of the following…
Refrigerant Leaks
Refrigerant leaks can certainly be the cause of hissing in an AC unit. If your air conditioner is leaking refrigerant, you may hear a hissing sound. This is because the refrigerant is escaping from the system. In some cases, you might see the refrigerant leaking around your AC system. Not a good sign, but one we can fix!AC refrigerant is the liquid used in your air conditioner system to the indoor air cooler inside your home. It filters through different parts of the air conditioner. It also moves the heat from inside the house and pushes it outside, in order to keep the house cool and not stuffy and warm. So, if you have a refrigerant leak - you’re not getting cool air at all.A refrigerant leak is a serious issue and needs to be addressed by a Mom-Appproved HVAC technician.
Clogged Air Filter
You could also have a clogged air filter. If the air filter is clogged, it can cause the air conditioning unit to work harder than it should. This can lead to a hissing sound coming from the unit. This is one that a handy homeowner can check on their own. If you look at the air filter and it's dirty, replace it! That might just solve the problem. Of course, we're happy to inspect the system for any other issues, and can help you with the filter replacement if you wish.
Dirty Condenser Coils
Dirty condenser coils could be a reason for the hissing noise coming from your AC unit. If the condenser coils are dirty, they can cause the air conditioning unit to make a hissing sound. This is because the coils are working harder than they should be. Your coils will need to be cleaned.Your air conditioner’s condenser coils are what help to get rid of the heat that your air conditioner pulls from within your home. The air conditioner condenser coils are outside of your your home and are reminiscent of metal fins. If something is wrong and the refrigerant in your air conditioner gets hot, it spreads to the condenser coils.If your AC system’s condenser coils get dirty or backed up, they can’t release heat as well as they used to and as a result, your air conditioner unit needs to work harder, which makes it less efficient and could make the system start hissing. This is why it's important to schedule an AC tune-up at least once a year in order to keep the condenser coils clean and your system from making concerning noises.
Faulty Expansion Valve
Another issue your HVAC system might have is a faulty expansion valve. The expansion valve is what pushes the flow of refrigerant through your air conditioning system. If it is faulty, it can cause the air conditioning unit to make that dreaded hissing sound. We can inspect the valve and replace it if needed.
Less Common Reasons Your Air Conditioner is Hissing
In more rare cases, there could be a lesson common culprit causing your air conditioner to start hissing when you have it running. These are more serious issues that will require a proper diagnosis and solution from one of our Mom-Approved HVAC technicians.These are some less common reasons your air conditioner might produce a hissing sound, including…
Restricted Refrigerant Flow
Restricted refrigerant flow could be the cause of your woes. If the refrigerant flow in your air conditioning system is restricted, it can make the unit start to hiss. This can occur due to a blockage in the refrigerant line or clogging in the expansion valve.
Loose/Leaking Ductwork
If the ductwork in your home is loose or leaking, it can cause a hissing sound. Your air conditioning system is meant to have a specific amount of pressure. Faulty ductwork can let air out of leaks or cracks, causing a troubling hissing sound.
Electrical Issues
Electrical issues can cause a hissing sound in your air conditioner. If there is some sort of electrical issue, it can snowball into problems with other parts of your home. Hissing sounds from your HVAC system can occur when the electrical connections in your air conditioner are loose or the motor is on its way out.
Fan Problems
You could hear a hissing sound if the fan in your air conditioning unit is damaged or dirty. In this case, the fan may need to be cleaned or replaced by a Mom-Approved technician from our [company_name] team.
Call on Our Team of Mom-Approved HVAC Experts!
Looking for a team of air conditioning experts in a family owned HVAC company? Look no further than [company_name]! Our team of Mom-Approved technicians are trained, knowledgeable, and ready to take on any task you have for us.We offer free consultations and we’re ready to provide you with expert guidance and top-notch repair, installation or maintenance services. When you give us a call, you’ll be working with a team of technicians that genuinely care about the work they do and never do anything halfway. We treat our customers like family and never try to upsell or mislead. We’re all about honesty and integrity.So if you find your air conditioner is hissing, not producing cool air, making loud noises, or any other unusual behaviors, give [company_name] a call now! We’re on the job and will get your AC system back to working order in no time.We service residents in Camarillo and the Ventura County area. We’re Mom-Approved because we’re all about family first. Give us a call today and get a free consultation with our team at [company_name] today!
Related Articles:
Still not convinced you should call the professionals? While we strongly recommend calling a certified HVAC technician to inspect the problem, especially if your air conditioning is making a hissing noise, we understand the desire to troubleshoot things first. Here are the 5 things we recommend trying before you call for AC repair service.
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About the Author
Kevin Allen
Co-Founder & Service Lead
Co-founded AirWorks in 2010 and has worked in Ventura County HVAC since 2002. Leads the service and installation crews — and the fix-what's-actually-broken ethic the company was built on.
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