A hissing noise inside your HVAC system should not be ignored. Among the probable causes are leaking5 refrigerant lines, an internal valve leak or a serious problem with your compressor. If the hissing noise is coming from your air ducts, then you could have leaking air ducts. This is annoying, but not necessarily a cause for alarm. A hissing sound may be a sign for 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 ceases after a few seconds, you may not have any issues. 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 paired with a hissing sound? This could indicate a refrigerant leak. If a refrigerant leak presents itself, you may hear a slight hissing sound as the refrigerant escapes via the leak. Refrigerant escapes as a gas and can be a major 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 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 without repair, the leak will worsen. When it does, the hissing sound will sometimes grow louder, which can be a tell if you’re looking for a cause. You must maintain adequate pressure in your system for it operate correctly, and leaks create additional health and mechanical problems. You want 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 called a condenser unit. Listen quietly for the hissing noise. If the compressor is the problem, this could be an unsafe situation because it is a sign that the pressure inside the compressor is too high. If you hear hissing, whistling, or shrieking coming from your compressor, shut off your air conditioner pronto and call a professional technician.
Compressors are some of the most costly parts to repair or replace inside an AC unit. Compressors are the part responsible for circulating refrigerant through the system. You cannot turn on an air conditioner and cool your home sans compressor. The cost is variable based on factors such as the type, unit size, and brand requirements. If you have a two stage compressor in your AC, you will 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 parts are installed and won’t accept substitutes. While it’s impossible to give a quote online because of the variable costs, the receipt is often large enough to think about a replacement in older units. This is why it’s critical to shut off the air conditioning and call a trustworthy HVAC company if you hear hissing sounds coming from the compressor.