Why is my AC making a hissing noise?

July 25, 2019

A hissing noise coming from your HVAC system should not be overlooked. Among the potential causes are leaky refrigerant lines, an internal valve leak or a serious failure with your compressor. If the hissing noise is originating from your ductwork, then you might have leaky air ducts. This is annoying, but not necessarily a reason to worry. A hissing sound could be a sign for any of these things, but we’ll try to narrow it down further.

Does the hissing sound stop after a few seconds?

If you hear a hissing noise that ends after a few seconds, you may not have any problems. That can be refrigerant in your expansion valve, which is part and parcel of the normal operation of your HVAC mechanicals.

Is the AC Making a Hissing Sound with Bubbling Noises?

Are you hearing a bubbling sound along with a hissing sound? This could indicate a refrigerant leak. If a refrigerant leak presents itself, you might hear a light hissing sound as the refrigerant escapes from the leak. The coolant escapes as a gas and can be a serious health concern. If you notice signs of a refrigerant leak, turn off the unit and call a expert HVAC company to come take a look.

If the issue is a valve leak, it should be repaired by a technician as soon as possible. The job of the valves is to help with the pressurization of the refrigerant gas and if unresolved, the leak will worsen. When it does, the hissing sound will often intensify, which can be a sign if you’re looking for a cause. You must maintain adequate pressure in your system for it cool your home, and leaks create additional health and maintenance problems. It’s best to get this fixed quickly if possible.

Are Hissing Noises Coming from the Compressor?

The compressor can be found in the outdoor air conditioning unit, which is also known as a condenser. Listen around here for the hissing noise. If it turns out that the compressor is the cause, this could be an unsafe situation because it is an indication that the pressure in the compressor is too great. If you hear hissing, whistling, or shrieking coming from your compressor, switch off your air conditioner without delay and call a professional technician.

AC compressor located in exterior condenser unit 

Compressors are some of the most expensive parts to repair or replace inside an AC. Compressors are the part responsible for circulating refrigerant through the system. You cannot run an AC and cool your home without a compressor. The cost changes based on factors such as the type, unit size, and brand requirements. If you have a two stage compressor in your AC, you will need to replace it with a two stage compressor. It’s impossible to upgrade or downgrade the compressor type - your unit has specific requirements for what parts are installed and won’t accept substitutes. While it’s impossible to say how much a compressor replacement is because of the variable costs, the receipt is frequently big enough to consider a replacement in older units. This is why it’s critical to shut off the air conditioning and call a reputable HVAC company if you hear hissing sounds coming from the compressor.

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