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 potential causes are leaky refrigerant lines, an internal valve leak or a serious failure with your compressor. If the hissing noise is coming from your ductwork, then you could have leaking air ducts. This is annoying, but not necessarily a reason to worry. A hissing sound may be a sign for any of these things, but we’ll try to narrow it down a little further.

Does the hissing sound stop after a few seconds?

If you hear a hissing noise that ends 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 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 is present, you might hear a light hissing sound as the refrigerant escapes through the leak. Refrigerant escapes as a gas and can be a worrisome health concern. If you have signs of a refrigerant leak, turn off the AC and call a professional HVAC company to come evaluate the noise.

If the cause is a valve leak, it should be repaired by a professional as soon as possible. The job of the valves is to help with the pressurization of the refrigerant gas and if unresolved, 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 must maintain adequate pressure in your system for it cool your home, 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 located in the exterior air conditioning unit, which is also known as a condenser unit. Listen nearby the condenser for the hissing noise. If you find the compressor is the issue, this could be an unsafe situation because it is a sign that the pressure within the compressor is too high. If you hear hissing, whistling, or shrieking coming from your compressor, power down your air conditioner immediately and call an expert 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 circulating refrigerant through the system. You cannot run an AC and cool your home sans compressor. The cost varies based on factors like the type, unit size, and brand requirements. If you have a two stage compressor now, you would 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 parts are installed and can’t be MacGyvered. While it’s impossible to provide estimates because of the variable costs, the receipt is frequently big enough to just do a replacement in older ACs. This is why it’s crucial to shut off the air conditioning and call a reliable HVAC company if you hear hissing sounds coming from the compressor.

Contact Us