Name what you notice
What kind of smell is it?
Do not group every odour under the same cause.
Follow the smell pattern
Why does your air conditioner smell when it starts?
The timing and type of smell matter. Buildup may be relevant, but smell alone is not a diagnosis.
The short answer: A stale or musty startup smell can justify checking filters and accessible internal areas. Burning, strong chemical or electrical smells require the system to be switched off and assessed.
Musty or staleCheck maintenance and visible buildup
Drain-likeConsider moisture and drainage as well as cleaning
Burning or electricalSwitch off and arrange technical assessment
Timing matters
When does the smell happen?
Record the pattern before requesting help.
- 01At startup only
Note how long the smell lasts after the unit starts.
- 02While running
Record whether it continues in one mode or every mode.
- 03After rain or humidity
Note any connection with moisture or weather.
- 04With a leak or noise
Mention any water, unusual sound, error code or performance change.
Accessible checks
What can you inspect safely?
Keep the system off while checking removable filters and visible openings.
Cleaning or assessment
Which response fits the signs?
Cleaning addresses accessible buildup; other causes may need technical work.
Cleaning may be relevant
- Stale or musty odour with visible internal buildup.
- Dirty filters and overdue maintenance.
- Accessible grime around the airflow path.
- No immediate electrical or safety concern.
Technical assessment is important
- Burning or electrical smell.
- Strong chemical smell of unknown origin.
- Persistent leak or drain issue.
- Error code, tripping or sudden failure.
Real MACC work
See the condition and the cleaned result.
Use genuine job evidence to understand the process without assuming every air conditioner has the same condition.
Before condition
Document what is visible without claiming every system is identical.
Professional process
Show access, containment, internal cleaning and reassembly.
Completion
Operate and check the system after the listed work is complete.
Service area
See what is available for your system.
MACC organises Sydney, Central Coast and Newcastle work through serviceable routes. Availability is checked before a time is offered.
SydneyWestern SydneyNorthern SydneySouthern SydneyCentral CoastNewcastle
Provide your email and system type once. You can then continue in Messenger and add the number of systems, suburb, photos or symptoms without repeating the form.
Quick answers
Questions people ask before contacting MACC
Can a musty smell confirm mould?
No. Smell alone cannot identify the material or the complete cause.
Should I keep running a unit with a burning smell?
No. Switch it off and arrange technical assessment.
Will washing filters remove the smell?
It may help if the filters are the only issue, but internal buildup or drainage problems can remain.
Can professional cleaning guarantee every smell is removed?
No. Cleaning addresses accessible contamination; unrelated faults may require separate work.
Need help with your system?
Continue in Messenger after one short identification step.
Once your email and system type are recorded, every contact button takes you directly back to Messenger.