Why is my AC making a hissing noise?

July 25, 2019

A hissing noise inside your HVAC system is not something to be ignored. Among the probable causes are leaking5 refrigerant lines, an internal valve leak or a serious issue with your compressor. If the hissing noise is originating from your air ducts, then you might have leaking air ducts. This is annoying, but not necessarily something to panic over. A hissing sound could indicate any of these things, but we’ll try to narrow it down a little more.

Does the hissing sound end after a few seconds?

If you hear a hissing noise that ceases 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 day to day operation of your HVAC mechanicals.

Is the AC Making a Hissing Sound with Bubbling Noises?

Are you hearing a bubbling sound paired with a hissing sound? This may indicate a refrigerant leak. If a refrigerant leak is present, you may hear a slight hissing sound as the refrigerant escapes via the leak. It escapes as a gas and can be a major health concern. If you have signs of a refrigerant leak, turn off the unit and call a expert HVAC company to come evaluate the noise.

If the cause is a valve leak, it should be repaired by a professional as soon as possible. The job of the valves is to help with the pressurization of the refrigerant gas and left alone, the leak will worsen. When it does, the hissing sound will sometimes grow louder, which can be a tell if you’re looking for the cause. You need to maintain adequate pressure in your HVAC system for it operate correctly, and refrigerant leaks cause additional health and maintenance problems. It’s best to get this fixed post haste if possible.

Are Hissing Noises Coming from the Compressor?

The compressor is located in the exterior air conditioning unit, which is also known as a condenser unit. Listen around here for the hissing noise. If the compressor is the issue, this could be an unsafe situation because it is a signal that the pressure in the compressor is too much. If you hear hissing, whistling, or shrieking coming from your compressor, shut off your air conditioner without delay and call an expert technician.

AC compressor located in exterior condenser unit 

Compressors are some of the most expensive parts to repair or replace inside an AC unit. Compressors are the part responsible for circulating refrigerant through the system. You cannot turn on an air conditioner and cool your home without a compressor. The cost changes based on factors like the type, unit size, and brand requirements. If you have a two stage compressor in your AC, you will need to replace it with another two stage compressor. It’s impossible to upgrade or downgrade the compressor type - your unit has specific requirements for what components are installed and can’t be MacGyvered. While it’s impossible to provide estimates because of the variable costs, the receipt is often high enough to think about a replacement in older air conditioners. This is why it’s critical to shut off the air conditioning and call a trustworthy HVAC company if you hear hissing sounds coming from the compressor.

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