Why Is My AC Making a Hissing Noise?
Air conditioning units make some noise just by operating. However, if you hear an abnormal sound, such as a hissing noise, it could be a sign that your HVAC unit is not working properly.
Sometimes, an AC making hissing noises indicates a minor issue you can solve at home. Other times, hissing sounds can be a symptom of a more serious problem that requires professional service.
This short guide explores common reasons for a hissing air conditioner and includes topics such as:
- Common causes of a hissing AC unit
- Warning signs that require immediate attention
- Why ignoring hissing noises can be costly
- Steps to diagnose the problem
- Addressing hissing noises in your AC
Keep reading to discover what to do if you hear hissing from your HVAC system.
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Common Causes of a Hissing AC Unit
Some reasons you might hear consistent or intermittent hissing from your AC unit include:
- Refrigerant leaks. Leaking refrigerant can impact the cooling efficiency of your system, and if you lose too much refrigerant and keep operating the system, it can lead to severe damage.
- Compressor issues. When there’s a lot of internal strain on your system due to compressor issues or other faulty parts, pressures can build up, leading to hissing sounds.
- Leaky ducts. Damaged ductwork, such as small holes or rips, can cause hissing sounds in your walls or other home areas.
- Expansion valve issues. Malfunctioning valves may allow refrigerant or air to leak through, which can lead to hissing.
Warning Signs That Require Immediate Attention
Knowing the difference between a minor issue and a potentially serious malfunction that needs immediate attention can help you care for your AC unit. Some signs it’s time to call in a professional include:
- You’re hearing hissing noises and notice a correlated reduction in the effectiveness of your unit — for example, you aren’t experiencing the cooling or heating you expect.
- You notice a visible ice or frost buildup on the refrigerant lines or coils.
- Your energy bills are rising without any other explanation, such as increased electrical use in the home.
- You smell a chemical near the exterior unit, which can indicate that you have a refrigerant leak.
Why Ignoring Hissing Noises Can Be Costly
While hissing can sometimes indicate a minor problem that’s easy to fix, ignoring this sign of a needed repair can be disastrous. Whatever is causing the noise is not normal, and if left unchecked, it can develop into a larger problem. That can mean more time and money to fix or increased wear on your system, which shortens its lifespan.
Steps to Diagnose the Problem
To diagnose a problem related to a hissing AC unit, conduct the following steps:
- Move around your home while listening to the hiss to locate its origin.
- Check for visible signs of damage or icy buildups.
- Check that your air filters are clean and correctly installed.
- Call in a professional if you still can’t find a problem.
If you notice hissing coming from a single vent, you might need to clean it or remove an obstruction. However, you may need duct sealing or repair services if you hear hissing in the walls or ceiling.
Hissing at the register or intake vent may be related to a filter problem. That can be an easy DIY fix — you might need to replace the filter. On the other hand, hissing near the exterior unit or compressor may indicate mechanical issues that need professional attention.
HVAC professionals can help you understand the best approach to address AC hissing issues.
Addressing Hissing Noises in Your AC
There are some steps you can take to resolve simple problems causing hissing noises in your AC, but in most cases, it’s best to call a professional. Professional HVAC technicians have the capability and the know-how to fix the problem quickly and without causing other potential issues.
Stop the Noise — Call Champion Air for Expert AC Repairs
Return your home to a peaceful location that’s comfortable to lounge in with high-quality AC repair services. The team at Champion Air works quickly to understand why your AC unit is making hissing noises and address the problem to ensure your unit is operating efficiently.
