Very often our inspections report on very noisy air conditioning systems which either need remedial work or replacement. Building owners can often save time and money by being aware of the usual noise output from their air conditioning system and should then be alerted if there is any change because this indicates there is an issue with the system somewhere.
To start tracking down the cause (and cure) of noises from your air conditioning or heat pump system it will be necessary to listen carefully to determine the location of the sound. This is the first and most obvious tactic. There may be ductwork noises or the noise may be conducted by the ductwork from another location that may not even be anything to do with the air conditioner or heat pump equipment.
It is also important to try and identify the type of noise to give you more clues.
Buzzing sounds (also crackling) at electrical components anywhere, including compressor relay switches, electrical connections at any component, and more seriously, at circuit breakers can be an indication of arcing and an electrical problem needing prompt attention.
Clicking noises from relays & controls can be heard either at the compressor/condenser or at the indoor air handler unit: A failing or defective thermostat or a defective control can cause relays to click on and off repeatedly.
Animals in the ductwork can make a variety of sounds, depending on the creature from fluttering and clanging (a trapped bird), scratching, and gnawing (squirrel, mouse, or rat), buzzing, and humming (bees or wasps).
Other noises duct systems make are hisses, whistles, roars, and occasionally clunk or clank sounds from expanding or contracting metal ductwork. These sounds can be due to a bad vibration dampener, or other component.
Clicking and ticking sounds in air conditioning systems can be traced to a loose or bent fan blade hitting an obstruction.
Bubbling, clicking, duct noises, fan noises and vibration dampener noises can all be related to the air handler/ indoor blower-cooling unit.
Clicking, rumbling, ticking, rattling, clanging and clunking at start-up can be down to loose hardware components in the compressor.
Sometimes there can even be voices heard in the ductwork! HVAC ducts in buildings can transmit sound between building areas, more so when air is not moving through the ducting system.
Becoming familiar with the normal sounds of your air conditioning system means you will be alert to any abnormalities so will be able to trace any problems sooner, leading to less expensive repairs.
