Why is my AC making a hissing noise?

July 25, 2019

A hissing noise inside your HVAC system is not something to be disregarded. Among the potential causes are leaking5 refrigerant lines, an internal valve leak or a serious problem with your compressor. If the hissing noise is originating from your ducts, 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 a little more.

Does the hissing sound stop after a few seconds?

If you hear a hissing noise that stops after a few moments, you may not have any issues. That could be refrigerant in your expansion valve, which is part of the normal day to day operation of your HVAC system.

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 might notice a slight hissing sound as the refrigerant escapes via the leak. The coolant 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 take a look.

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 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 any leak will create 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 outdoor air conditioning unit, which is also called a condenser. Listen around here for the hissing noise. If it turns out that the compressor is the cause, this could be a dangerous situation because it is a signal that the pressure inside the compressor is too much. If you hear hissing, whistling, or shrieking coming from your compressor, shut off your air conditioner pronto and call a professional technician.

AC compressor located in exterior condenser unit 

Compressors are some of the most expensive units to repair or replace inside an AC. Compressors are the part responsible for pushing refrigerant through the system. You cannot power on an HVAC system and cool your home without a compressor. The expense varies based on factors like the type, unit size, and brand requirements. If you have a two stage compressor in the unit today, 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 in order to operate safely. While it’s impossible to say how much a compressor replacement is because of the variable costs, the expense is frequently high enough to think about a replacement in older units. This is why it’s critical to shut off the air conditioning and call a reliable HVAC company if you hear hissing sounds coming from the compressor.

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