Noise + Vibration Complaint Handling Reference

Why this matters

Customer says "this is too loud" OR "it's vibrating the walls." Equipment that works perfectly but annoys customer = customer dissatisfaction. The tech who understands noise / vibration sources + remedies can address customer concerns without unnecessary equipment replacement. This is the field card.

Noise vs vibration

Noise:

• Sound waves traveling through air
• Measured in decibels (dB)
• Frequency in Hz (low rumble, high whine)

Vibration:

• Mechanical movement transmitted through structure
• Felt in walls, floors, sometimes objects
• Often more annoying than airborne noise (passes through structure regardless)

Both can come from same equipment. Different remediation.

Decibel levels for context

• 0 dB: hearing threshold
• 30 dB: whisper
• 60 dB: normal conversation
• 70 dB: vacuum cleaner
• 80 dB: typical city traffic
• 90 dB: lawn mower (hearing damage with extended exposure)
• 100 dB: chainsaw
• 110 dB: rock concert
• 120 dB: jet engine

Equipment standards typically:

• Indoor air handler: 50-65 dB
• Outdoor AC unit: 60-75 dB
• Refrigerator: 30-45 dB

What's "loud" is subjective; customers vary.

Common noise sources

HVAC indoor:

• Blower motor (loudest usually)
• Air rushing through ducts
• Burner ignition (gas)
• Inducer fan
• Filter rack vibrating
• Cabinet vibration

HVAC outdoor:

• Compressor (loudest in condenser)
• Condenser fan
• Refrigerant flow sounds
• Vibration through pad

Appliances:

• Refrigerator (compressor, fan, defrost)
• Dishwasher (pump, motor)
• Washer / dryer (motor, drum, vibration)
• Garbage disposal

Plumbing:

• Water flow (high-velocity at faucets)
• Water hammer
• Toilet fill
• Drain venting

Garage door:

• Motor (chain drives loudest; belt drives quieter)
• Door rolling on tracks
• Spring tension
• Belt squeaking

Roof equipment:

• Rooftop AC unit on commercial / multi-family
• Whirlybird vents
• Loose flashing in wind

Diagnosing the noise

When customer reports:

1. Listen with customer:

• Have them point to where + when
• Replicate conditions
• Verify what they hear

1. Identify source:

• Sometimes obvious
• Sometimes need to start / stop components
• Stethoscope OR sound meter helps

1. Determine if normal OR abnormal:

• New noise = problem
• Always there = part of equipment design
• Worse over time = developing issue

1. Recommend solution:

• Fix the cause
• Mitigate (insulation, isolation)
• Customer education ("this is normal")

Vibration sources

Vibration usually from:

• Motor imbalance
• Compressor (HVAC, refrigerator)
• Pump (plumbing, sump, pool)
• Loose mounting
• Building structure resonance

Remediation approaches

Source elimination:

• Replace failing component
• Balance motor
• Tighten mounting

Source isolation:

• Rubber feet / vibration pads
• Spring isolators (for heavy equipment)
• Flexible connections (electrical, gas, ductwork)

Sound dampening:

• Sound-absorbing material (acoustic foam, insulation)
• Sound barrier (mass; sometimes drywall layer)
• Enclosure

Distance:

• Move equipment farther from living space
• Rare option after install

Sound-blocking:

• Wall thickness
• Insulation in walls
• Acoustic ceiling tiles

HVAC noise remediation

Air handler / furnace too loud:

• Verify proper filter (clogged filter = motor straining)
• Check blower wheel balance
• Verify proper ductwork sizing (small duct = high velocity = loud)
• Acoustic lining on supply / return at unit
• Variable-speed motors are quieter than single-speed

Outdoor AC too loud:

• Verify proper refrigerant charge
• Check for loose / damaged fan blade
• Vibration pad under unit
• Sound barrier (fence, wall) but with airflow clearance

Ductwork noise:

• Velocity (CFM / duct area) too high
• Larger duct, smoother runs
• Acoustic lining
• Flexible connections to equipment

Whistling registers:

• Damper partially closed
• Register opening too small
• High velocity through register

Plumbing noise remediation

Water hammer:

• Quick-closing valves (washer, dishwasher)
• Install water hammer arrestor at fixture
• Reduce water pressure if excessive (40-60 PSI ideal)

Banging pipes (when starting flow):

• Pipes loosely supported
• Air in lines
• Strap pipes to studs
• Check pressure-reducing valve

Singing pipes / whistling:

• Worn valve seat (faucet OR shutoff)
• Excessive water pressure
• Adjust pressure-reducing valve OR replace fixture

Toilet vibration:

• Old fill valve
• Replace with quieter model

Sink drain rumbling:

• Air admittance valve (AAV) failing
• OR vent stack issue
• Replace AAV OR address vent

Appliance noise

Refrigerator:

• Compressor noise (cyclical, normal)
• Knocking compressor: failing
• Whining: condenser fan
• Vibration: not level OR loose pan

Washer:

• Tumbling = normal
• Banging = unbalanced load
• Walking = uneven surface OR worn shocks
• Squealing = belt OR bearing

Dryer:

• Tumbling normal
• Squealing = drum bearing
• Thumping = drum support OR foreign object

Dishwasher:

• Pumping = normal
• Grinding = food in disposal sump
• Loud all-cycle = pump bearing failure

Garage door noise

Squeaking + rattling:

• Dry hinges + rollers
• Lubricate (silicone OR garage-door specific; not WD-40)
• Worn rollers
• Loose hardware

Loud motor:

• Chain drive vs belt drive
• Customer can upgrade for quieter operation
• Mounting on living-space wall = bedroom noise

Customer subjective vs objective

Customer's complaint may be:

• "Too loud" but objectively normal
• "Too loud" + objectively excessive
• Vibration but no detectable equipment fault

For objective measurement:

• Decibel meter (smartphone apps OK for indicative)
• Compare to ambient
• Compare to spec for that equipment
• Document

If equipment is within spec:

• Educate customer
• Suggest cosmetic remediation (acoustic foam, distance)
• Customer may need to accept (replacement isn't always the answer)

When customer just doesn't like the noise

Sometimes the equipment works perfectly + customer doesn't like the sound:

• New equipment may have different sound than old (customer used to old)
• Customer's home has unusual acoustic properties
• Hearing sensitivity varies

Honest answer:

• "Your [equipment] is operating normally"
• "Here's options to reduce the noise you hear..."
• Customer chooses what to invest

Some customers will not be satisfied; some equipment can't be made silent.

When complaint is from neighbor

Common with outdoor units:

• Neighbor complains about your customer's AC
• Local noise ordinance enforced
• Custom solution required (sound barrier, relocate)

This is between neighbors + customer; you advise.

Building noise considerations

References

• ASHRAE 62.2 (Indoor Air Quality + Ventilation)
• HVI (Home Ventilating Institute) sound ratings
• AHRI 270 (Sound Performance Rating of Outdoor Unitary Equipment)
• Local noise ordinances (varies by municipality)
• Manuall internal: HVAC Common Error Codes, Common Bearings + Lubricants