Why is my AC making a hissing noise? 

A hissing noise coming from your HVAC system should not be disregarded. Among the possible causes are leaking refrigerant lines, an internal valve leak or a serious failure with your compressor. If the hissing noise is originating from your ductwork, then you could have leaky 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 more. 

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 problems. That might be refrigerant in your expansion valve, which is part and parcel of the normal 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 notice a slight hissing sound as the refrigerant escapes through the leak. The coolant escapes as a gas and can be a serious health concern. If you see signs of a refrigerant leak, turn off the AC and call a qualified HVAC company to come take a look. 

If the cause 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 tell if you’re looking for the cause. You need to maintain proper pressure in your system for it cool your home, and refrigerant leaks cause additional health and mechanical problems. You want to get this fixed quickly if possible. 

Are Hissing Noises Coming from the Compressor? 

The compressor can be located in the exterior air conditioning unit, which is also called a condenser. Listen around here for the hissing noise. If the compressor is the problem, this could be a dangerous situation because it is a signal that the pressure in the compressor is too high. If you hear hissing, whistling, or shrieking coming from your compressor, turn off your air conditioner pronto and call an expert technician. 

Compressors are some of the most expensive parts to repair or replace inside an AC. Compressors are the part responsible for pushing 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 in your AC, you would need to replace it with a two stage compressor. It’s not possible to upgrade or downgrade the compressor type – your unit has specific requirements for what parts are installed in order to operate safely. While it’s impossible to provide estimates because of the variable costs, the expense is often big enough to just do 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.