Why is my AC making a hissing noise?

July 25, 2019

A hissing noise coming from your HVAC system should not be disregarded. Among the probable causes are leaky refrigerant lines, an internal valve leak or a serious issue with your compressor. If the hissing noise is heard from your air ducts, then you could have leaky air ducts. This is annoying, but not necessarily something to panic over. A hissing sound may be a sign for 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 ends after a few seconds, you may not have any issues. That might 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 paired with a hissing sound? This can indicate a refrigerant leak. If a refrigerant leak is present, you might notice a light hissing sound as the refrigerant escapes through the leak. The coolant escapes as a gas and can be a worrisome health concern. If you have signs of a refrigerant leak, shut down the AC and call a expert HVAC company to come evaluate the noise.

If the issue is a valve leak, it should be repaired by a qualified technician 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 increase, which can be a tell if you’re looking for a cause. You must maintain adequate pressure in your HVAC system for it cool your home, and refrigerant leaks cause additional health and maintenance problems. You ought to get this fixed quickly if possible.

Are Hissing Noises Coming from the Compressor?

The compressor can be found in the outdoor air conditioning unit, which is also called a condenser unit. Listen nearby the condenser for the hissing noise. If the compressor is the issue, this could be an unsafe 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, power down your air conditioner immediately and call an expert technician.

AC compressor located in exterior condenser unit 

Compressors are some of the most pricey units to repair or replace inside an AC. Compressors are the part responsible for cycling refrigerant through the system. You cannot run an AC and cool your home without a compressor. The cost varies based on factors such as 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 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 and won’t accept substitutes. While it’s impossible to provide estimates because of the variable costs, the bill is often big 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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