When temperatures drop across the Surf Coast, Bellarine and Geelong region, many homeowners switch on their gas heaters for the first time in months — only to notice an unusual smell coming from the unit.
Sometimes this is harmless. Other times, it can indicate a serious safety issue that should never be ignored.
In this guide, we’ll explain the most common gas heater smells, what they may mean, and when it’s time to arrange professional gas heater servicing
Is It Normal for a Gas Heater to Smell?
A mild smell when first turning on your heater after months of non-use can be completely normal.
Dust often settles inside the unit during warmer months. When the heater is switched back on, that dust burns off and can create a temporary “hot dust” smell for a short period.
This smell should:
- disappear within a few minutes,
- not be overpowering,
- and not cause headaches, nausea, or irritation.
If the smell continues, becomes stronger, or smells unusual, it may indicate a fault that requires professional attention.
Different Gas Heater Smells — And What They Could Mean
Burning Dust Smell
This is the most common and usually the least concerning smell.
Cause:
- Dust build-up on internal components during periods of non-use.
What to do:
- Allow the heater to run for several minutes with ventilation.
- If the smell persists, book a service inspection.
Rotten Egg or Sulphur Smell
This smell should always be taken seriously.
Natural gas itself is odourless, but suppliers add a chemical called mercaptan to make leaks easier to detect.
Possible causes:
- gas leak,
- loose fittings,
- damaged gas connections,
- faulty valves.
What to do immediately:
- turn the heater off,
- avoid flames or electrical switches,
- ventilate the area,
- and contact a licensed gas plumber as soon as possible.
If the smell is strong or widespread, leave the property and contact emergency services or your gas provider.
Musty or Damp Smells
A damp smell can sometimes indicate:
- moisture inside ducting,
- mould build-up,
- blocked filters,
- or poor airflow.
This is more common in:
- older ducted systems,
- heaters unused for long periods,
- homes with high humidity.
Regular maintenance and cleaning can help prevent these issues.
You can also read more about the importance of servicing your gas heater before winter arrives.
Metallic or Electrical Smells
A sharp metallic or electrical smell may indicate:
- overheating components,
- wiring faults,
- motor issues,
- or internal damage.
If you notice this type of smell:
- switch the heater off,
- avoid continued operation,
- and arrange gas heater repairs promptly.
Could a Smelly Gas Heater Mean Carbon Monoxide?
Potentially — yes.
While carbon monoxide itself has no smell, faults that produce dangerous gases can sometimes also create unusual odours or poor combustion symptoms.
Warning signs may include:
- headaches,
- dizziness,
- nausea,
- excessive condensation,
- yellow instead of blue flames,
- or soot marks around the heater.
Learn more about carbon monoxide risks and why regular servicing is so important for gas heater safety.
How Often Should Gas Heaters Be Serviced?
Most manufacturers and gas safety professionals recommend servicing gas heaters every two years — or more frequently for older systems or heavy use.
Professional servicing can help:
- improve efficiency,
- reduce breakdowns,
- extend heater lifespan,
- improve indoor air quality,
- and identify potential safety issues early.
Signs Your Gas Heater Needs Immediate Attention
Contact a professional if you notice:
- persistent unusual smells,
- headaches when heater is running,
- yellow flames,
- soot marks,
- pilot light problems,
- excessive condensation,
- unusual noises,
- or difficulty starting the heater, or it not staying lit for very long.
Ignoring early warning signs can lead to larger repairs and serious safety risks.
While unusual smells can sometimes be harmless, they can also be one of several warning signs that your heater may need professional attention. If you've noticed other issues such as poor heating performance, unusual noises, frequent shutdowns, or rising energy bills, read our guide on the 7 warning signs your gas heater needs servicing to learn what to watch for.
Professional Gas Heater Servicing in Geelong
At Tomlinson Plumbing, we provide professional gas heater servicing, fault diagnosis, and repairs across Torquay, Geelong, Ocean Grove and surrounding areas.
Whether your heater smells unusual, isn’t operating efficiently, or simply hasn’t been serviced in years, we can help ensure your system is operating safely and correctly.
Call us on 5261 2422 today, or contact us via our website