Why is my AC making a hissing noise?

July 25, 2019

A hissing noise coming from your HVAC system is not something to be overlooked. Among the possible causes are leaky refrigerant lines, an internal valve leak or a serious issue with your compressor. If the hissing noise is coming from your ducts, then you might have leaky air ducts. This is annoying, but not necessarily a cause for alarm. A hissing sound may indicate 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 seconds, you may not have any problems. That could 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 along with a hissing sound? This could indicate a refrigerant leak. If a refrigerant leak presents itself, you may hear a light hissing sound as the refrigerant escapes from the leak. Refrigerant escapes as a gas and can be a major health concern. If you notice signs of a refrigerant leak, shut down your HVAC and call a professional HVAC company to come take a look.

If the issue is a valve leak, it should be repaired by a professional 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 increase, which can be a signal if you’re looking for the cause. You need to maintain adequate pressure in your HVAC system for it run as intended, and any leak will create additional health and mechanical problems. You ought to get this fixed quickly 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 unit. Listen nearby the condenser for the hissing noise. If it turns out that the compressor is the issue, this could be an unsafe situation because it is a sign that the pressure in the compressor is too high. If you hear hissing, whistling, or shrieking coming from your compressor, power down your air conditioner without delay 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 air conditioner. Compressors are the part responsible for circulating refrigerant through the system. You cannot run an AC and cool your home sans compressor. The cost is variable based on factors like the type, unit size, and brand requirements. If you have a two stage compressor now, you will need to replace it with another two stage compressor. It’s not possible to upgrade or downgrade the compressor type - your unit has specific requirements for what compressors are installed in order to operate safely. While it’s impossible to give a quote online because of the variable costs, the expense is often large enough to think about a replacement in older units. This is why it’s crucial to shut off the air conditioning and call a reputable HVAC company if you hear hissing sounds coming from the compressor.

Contact Us