Why is my AC making a hissing noise? 

A hissing noise coming from your HVAC system is not something to be ignored. Among the probable causes are leaking refrigerant lines, an internal valve leak or a serious problem with your compressor. If the hissing noise is heard from your ducts, then you may 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 ceases after a few moments, you may not have any issues. That might be refrigerant in your expansion valve, which is a 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 can indicate a refrigerant leak. If a refrigerant leak presents itself, you might notice a light hissing sound as the refrigerant escapes through the leak. It escapes as a gas and can be a serious health concern. If you have signs of a refrigerant leak, power down the AC and call a qualified HVAC company to come evaluate the noise. 

If the problem is a valve leak, it should be repaired by a qualified technician as soon as possible. The job of the valves is to manage 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 a cause. You must maintain adequate pressure in your HVAC system for it operate correctly, and leaks 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 can be found in the exterior air conditioning unit, which is also known as a condenser unit. Listen quietly for the hissing noise. If the compressor is the issue, this could be an unsafe 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, shut off your air conditioner immediately and call a professional technician. 

Compressors are some of the most expensive parts to repair or replace inside an air conditioner. Compressors are the part responsible for circulating refrigerant through the system. You cannot power on an HVAC system and cool your home without a compressor. The cost 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 impossible 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 large enough to consider a replacement in older units. 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.