Why is my AC making a hissing noise?

July 25, 2019

A hissing noise coming from your HVAC system should not be ignored. Among the probable causes are leaky refrigerant lines, an internal valve leak or a serious failure with your compressor. If the hissing noise is coming from your ducts, then you might have leaking air ducts. This is annoying, but not necessarily a cause for alarm. A hissing sound may 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 ceases after a few moments, you may not have any issues. That might be refrigerant in your expansion valve, which is a part 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 can indicate a refrigerant leak. If a refrigerant leak presents itself, you may hear a light hissing sound as the refrigerant escapes through the leak. It escapes as a gas and can be a worrisome health concern. If you notice signs of a refrigerant leak, power down the unit and call a qualified HVAC company to come evaluate the noise.

If the cause is a valve leak, it should be repaired by a qualified technician as soon as possible. The job of the valves is to manage the pressurization of the refrigerant gas and without repair, the leak will worsen. When it does, the hissing sound will sometimes grow louder, which can be a signal if you’re looking for the cause. You must maintain proper pressure in your system for it run as intended, and refrigerant leaks cause additional health and mechanical problems. You ought to get this fixed post haste if possible.

Are Hissing Noises Coming from the Compressor?

The compressor is found in the exterior air conditioning unit, which is also known as a condenser. Listen quietly for the hissing noise. If you find the compressor is the cause, this could be a dangerous situation because it is an indication that the pressure inside the compressor is too much. If you hear hissing, whistling, or shrieking coming from your compressor, switch off your air conditioner pronto and call an expert technician.

AC compressor located in exterior condenser unit 

Compressors are some of the most costly units 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 sans compressor. The expense is variable based on factors like the type, unit size, and brand requirements. If you have a two stage compressor in your AC, you would 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 won’t accept substitutes. While it’s impossible to give a quote online because of the variable costs, the expense is frequently large enough to think about a replacement in older units. 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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