A hissing noise coming from your HVAC system is not something to be overlooked. Among the potential causes are leaky refrigerant lines, an internal valve leak or a serious failure with your compressor. If the hissing noise is heard from your air ducts, then you might have leaky air ducts. This is annoying, but not necessarily a cause for alarm. A hissing sound could indicate any of these things, but we’ll try to narrow it down further.
Does the hissing sound end after a few seconds?
If you hear a hissing noise that ceases after a few seconds, you may not have any issues. That could be refrigerant in your expansion valve, which is part of the normal day to day 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 develops, you may 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 notice signs of a refrigerant leak, power down the AC and call a professional 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 help with the pressurization of the refrigerant gas and left alone, the leak will worsen. When it does, the hissing sound will increase, which can be a tell if you’re looking for the cause. You need to maintain proper pressure in your HVAC system for it operate correctly, and any leak will create additional health and maintenance problems. You want to get this fixed quickly if possible.
Are Hissing Noises Coming from the Compressor?
The compressor is found in the outdoor air conditioning unit, which is also known as a condenser unit. Listen quietly for the hissing noise. If you find the compressor is the issue, this could be an unsafe 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, switch off your air conditioner without delay and call a professional technician.
Compressors are some of the most expensive parts to repair or replace inside an AC. Compressors are the part responsible for cycling refrigerant through the system. You cannot power on an HVAC system 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 a 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 can’t be MacGyvered. While it’s impossible to give a quote online because of the variable costs, the expense is often high enough to consider a replacement in older units. This is why it’s critical to shut off the air conditioning and call a reputable HVAC company if you hear hissing sounds coming from the compressor.