Why is my AC making a hissing noise?

July 25, 2019

A hissing noise inside your HVAC system should not be overlooked. Among the possible causes are leaking5 refrigerant lines, an internal valve leak or a serious problem with your compressor. If the hissing noise is coming from your ductwork, then you may 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 further.

Does the hissing sound end after a few seconds?

If you hear a hissing noise that ends after a few moments, 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 paired with a hissing sound? This could 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 serious health concern. If you see signs of a refrigerant leak, power down the AC and call a expert HVAC company to come inspect the system.

If the problem is a valve leak, it should be repaired by a 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 adequate pressure in your HVAC system for it operate correctly, and leaks create 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 found in the outdoor air conditioning unit, which is also known as a condenser unit. Listen nearby the condenser for the hissing noise. If it turns out that the compressor is the issue, this could be a hazardous situation because it is a sign that the pressure inside the compressor is too much. If you hear hissing, whistling, or shrieking coming from your compressor, power down your air conditioner pronto and call an expert technician.

AC compressor located in exterior condenser unit 

Compressors are some of the most pricey parts to repair or replace inside an air conditioner. Compressors are the part responsible for cycling refrigerant through the system. You cannot turn on an air conditioner and cool your home sans compressor. The expense varies based on factors such as 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 impossible to upgrade or downgrade the compressor type - your unit has specific requirements for what parts are installed and won’t accept substitutes. While it’s impossible to give a quote online because of the variable costs, the bill is frequently big enough to think about a replacement in older units. This is why it’s so important to shut off the air conditioning and call a trustworthy HVAC company if you hear hissing sounds coming from the compressor.

Contact Us