Why is my AC making a hissing noise? 

A hissing noise inside your HVAC system should not be overlooked. Among the probable causes are leaking refrigerant lines, an internal valve leak or a serious failure with your compressor. If the hissing noise is heard from your ductwork, then you may 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 issues. That might be refrigerant in your expansion valve, which is part of the normal operation of your HVAC unit. 

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 might hear a slight hissing sound as the refrigerant escapes through the leak. The coolant escapes as a gas and can be a major health concern. If you see signs of a refrigerant leak, shut down your HVAC and call a professional HVAC company to come inspect the system. 

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 help with the pressurization of the refrigerant gas and left alone, the leak will worsen. When it does, the hissing sound will often intensify, which can be a sign if you’re looking for the cause. You must maintain proper pressure in your system for it cool your home, and refrigerant leaks cause additional health and mechanical problems. It’s best to get this fixed quickly if possible. 

Are Hissing Noises Coming from the Compressor? 

The compressor is located in the outdoor air conditioning unit, which is also called a condenser unit. Listen around here for the hissing noise. If the compressor is the cause, this could be a dangerous situation because it is a sign that the pressure within the compressor is too great. If you hear hissing, whistling, or shrieking coming from your compressor, switch off your air conditioner immediately and call an expert technician. 

Photo of AC unit showing location of compressor

Compressors are some of the most pricey parts to repair or replace inside an AC unit. Compressors are the part responsible for cycling refrigerant through the system. You cannot turn on an air conditioner and cool your home without a compressor. The expense is variable based on factors such as 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 compressors are installed in order to operate safely. While it’s impossible to give a quote online because of the variable costs, the receipt is frequently high enough to consider a replacement in older units. This is why it’s crucial to shut off the air conditioning and call a trustworthy HVAC company if you hear hissing sounds coming from the compressor. 

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