Why is my AC making a hissing noise?

July 25, 2019

A hissing noise inside your HVAC system is not something to be overlooked. Among the possible causes are leaking5 refrigerant lines, an internal valve leak or a serious failure with your compressor. If the hissing noise is heard from your ductwork, then you could have leaking air ducts. This is annoying, but not necessarily a reason to worry. A hissing sound may indicate 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 seconds, you may not have any issues. That could 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 can indicate a refrigerant leak. If a refrigerant leak presents itself, you may notice a light hissing sound as the refrigerant escapes via the leak. Refrigerant escapes as a gas and can be a serious health concern. If you have signs of a refrigerant leak, power down your HVAC and call a professional HVAC company to come inspect the system.

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 if unresolved, the leak will worsen. When it does, the hissing sound will often intensify, which can be a signal if you’re looking for the cause. You must maintain proper pressure in your system for it operate correctly, and leaks create additional health and mechanical problems. You want to get this fixed quickly if possible.

Are Hissing Noises Coming from the Compressor?

The compressor can be located 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 issue, this could be an unsafe situation because it is an indication that the pressure inside 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 unit. Compressors are the part responsible for pushing refrigerant through the system. You cannot run an AC and cool your home sans compressor. The pricing is variable 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 components 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 high enough to think about a replacement in older ACs. This is why it’s so important 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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