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Preparing your gas heater before winter can help identify issues early, support efficient operation where the appliance is in good working order, and reduce the chance of avoidable problems during the months you rely on heating most. This checklist is designed for any homeowner, whether you carry out annual upkeep on a familiar system or are looking after a gas heater for the first time.

It covers the visual inspections and basic maintenance tasks you can do yourself, how to test your heater before cold weather arrives, the signs that a professional service is needed, and when to call a licensed gasfitter. None of the steps below require technical knowledge or tools beyond what most households already have.

As your gas distributor, Australian Gas Networks is here to help you understand what to look out for and get the right support. If you ever smell gas at any point, stop what you are doing and go directly to our gas leaks and emergencies page for immediate guidance.

Key Summary

• Start Early: Run your heater on a mild day in late summer or early autumn to catch problems before cold weather arrives.

• DIY Checks: Many homeowners can carry out simple visual checks, filter checks, and a short test run, provided they follow the manufacturer’s instructions and do not open, adjust, or interfere with gas components.

• Professional Service: A full gas heater service, including any work on gas supply connections, burners, flues, heat exchangers, internal components or safety controls, must be performed by an appropriately licensed gasfitter. Book before winter when availability is better.

• Warning Signs: Unusual noises, persistent odours, or repeated ignition failures all warrant a call to a licensed gasfitter.

• Gas Emergency: If you smell gas at any point, turn off the heater, ventilate the space, leave the property, and call 1800 427 532 immediately.

Why preparing your gas heater before winter matters

Gas heaters that sit idle over summer can accumulate dust, develop minor faults, or lose efficiency without any obvious sign. A pre-season check can improve your heater run as intended and can help identify safety issues before they become serious. It also puts you in a better position practically: gasfitters are significantly more in demand  once winter sets in, so if your heater does need attention, organising it in autumn is far easier than finding someone available mid-July. 

What you can check yourself before winter

Several basic checks can be done by any homeowner without tools or technical knowledge. These checks help you spot obvious issues before booking a professional service. They do not replace a professional service, and none of them involve opening the heater or adjusting any internal components. If you are ever unsure whether something is within your scope, the safe choice is to contact a licensed gasfitter.

Visual inspection of external vents and flues

Walk around the outside of your home and locate the external vent outlets or flue for your gas heating system. These are typically grilles, louvres, or pipes mounted on an external wall or roof. Check that they are free from obvious blockages such as leaves, cobwebs, bird nests, debris, or objects that may have been placed in front of them over summer.

Blocked vents can prevent combustion gases from escaping properly, which is a safety concern. Clearing an accessible external vent of debris you can reach without tools or ladders is a reasonable task for a homeowner. If a vent appears damaged, corroded, or blocked in a way you cannot clear safely from the outside, contact a licensed gasfitter to inspect it before using the heater.

Checking and Replacing Filters

Ducted gas heating systems typically have a return air filter, usually located behind a grille on a wall or ceiling inside the home. This filter captures dust and particles before air enters the heating unit. A clogged filter restricts airflow, makes the system work harder than it needs to, and can reduce the warmth delivered to your rooms.

Locate your filter grille and remove it to inspect the filter inside. If it is visibly coated in dust and debris, it needs cleaning or replacing according to the manufacturer’s instructions. Many filters can be vacuumed gently or washed according to the manufacturer's instructions. Check your owner's manual for the correct method and replacement specifications for your model.

Not all gas heater types have user-accessible filters. Wall furnaces and some space heaters have different maintenance arrangements. If you are unsure whether your system has a filter or how to access it, consult your owner's manual or contact a licensed gasfitter. For an overview of the types of gas heating systems available in Australian homes, see AGN's gas heating buyer's guide.

Testing Your Heater Before Cold Weather Arrives

Turn your gas heater on for 10 to 15 minutes on a mild day before you need it in earnest. This gives you the opportunity to observe how it starts and runs without the pressure of needing heat urgently.

When you first switch the heater on after a long period of inactivity, a brief dusty or musty smell is common as accumulated dust burns off the heat exchanger. This typically clears within a few minutes. If the smell is persistent, resembles gas, or is accompanied by other changes such as unusual noises or error codes, turn the heater off.

If the answer to any of these is unsatisfactory, note what you observed and contact a licensed gasfitter before relying on the heater through winter.

IF YOU SMELL GAS AT ANY POINT

• Turn off the heater and all other gas appliances immediately.
• Do not operate any electrical switches, lights, or ignition sources.
• Open windows and doors to ventilate the space.
• Leave the property.
• Call the 24-hour gas emergency line on 1800 427 532 from a safe distance outside. Do not re-enter until the situation has been assessed as safe.

When to book a professional gas heater service

While homeowners can carry out the checks above, a full gas heater service must be performed by a licensed gasfitter. This is not a DIY task. Gas appliance servicing involves inspecting and adjusting internal components, testing gas pressure, checking for leaks, and testing safety controls. These steps require a licensed professional with the appropriate qualifications and equipment.

Energy Safe Victoria recommends all gas heaters be serviced at least every two years by a qualified gasfitter. Most manufacturers will also specify a service interval in your appliance manual. If you are overdue for a service, or if your heater showed any concerns during the test run above, this is the time to book.

A professional gas heater service typically covers the following, though inclusions vary by provider, heater type, and condition:

• Inspecting and cleaning the burner and combustion components
• Checking gas pressure and supply connections
• Testing the flue for correct operation and checking for blockages or spillage
• Inspecting the heat exchanger for cracks or deterioration
• Testing safety controls, thermostats, and ignition systems
• Checking for gas leaks at connections and fittings
• Testing for carbon monoxide spillage where applicable

When booking, ask the gasfitter what their standard service covers and whether there are any additional checks recommended for your specific heater type or age.

Signs your gas heater may need repair or replacement

• The heater does not ignite, or requires repeated attempts before starting
• The flame appears yellow or orange rather than blue, which may indicate
• incomplete combustion and should be assessed by a licensed gasfitter
• Unusual sounds during operation such as banging, rattling, loud popping, or persistent clicking
• Unusual odours during normal operation, other than a brief dusty smell when first switched on
• The heater runs but fails to heat the space adequately, or heats unevenly
• Warning lights or error codes are displayed on the unit
• Visible soot, staining, or unusual condensation around the heater or its flue

A professional gas heater service is a thorough inspection and maintenance check carried out by a licensed gasfitter. It is designed to assess how the heater is operating, identify any wear or developing faults, and confirm the appliance is safe and performing efficiently. This is not something a homeowner should attempt. 

A service commonly includes some or all of the following, depending on the heater type and its condition: 

• Inspecting and cleaning the burner and combustion components 
• Checking gas pressure and supply connections 
• Testing the flue and ventilation for correct operation 
• Inspecting the heat exchanger for cracks or deterioration 
• Testing safety controls, thermostats, and ignition systems 
• Checking for gas leaks at connections and fittings 
• Assessing overall system performance and flagging any components for attention 

If your heater is older and experiencing recurring faults, a licensed gasfitter can also advise on whether repair or replacement is the more practical option. See our article on gas heater service: signs you need one and what it costs for a more detailed look at each of these warning signs. 

How much does a gas heater service cost? 

There is no single gas heater service cost that applies across the board. Service costs vary depending on a number of factors, and quoting a specific price without knowing your situation would not give you an accurate picture.

The factors that typically influence what a service costs include: 

• Heater type: ducted gas heating systems are generally more involved to service than a single space heater, and this is reflected in the time and cost required 
• Location: gasfitters in regional or remote areas may include additional travel costs 
• Scope of the visit: a routine maintenance inspection differs from a visit that involves diagnosing an active fault or identifying unknown issues 
• Parts and repairs: if the gasfitter identifies components that need replacing during the service, these will typically be quoted separately 
• Age and condition of the heater: older units or those that have not been serviced recently may require more time and attention 

The most reliable way to understand what a gas heater service will cost for your specific heater and location is to contact two or three licensed gasfitters and ask for a quote, including what is covered in the service. You can find a licensed gasfitter in your area through your state’s relevant licensing authority.

How often should a gas heater be serviced? 

Energy Safe Victoria recommends all gas heaters be serviced at least every two years by a qualified gasfitter, and this guidance is echoed by state regulators across Australia, including WA's Department of Energy, Mines, Industry Regulation and Safety. Your appliance manufacturer may specify a different interval in the product manual, which takes precedence for warranty purposes. 

A practical rule of thumb: the older the heater, the more frequently it warrants attention. 

Timing matters too. Booking a service in autumn before the peak winter period generally means gasfitters are more likely to have availability, and any issues are identified before you need the heater most.  

For renters in Victoria, servicing obligations are specifically set by law. Under the Residential Tenancies Regulations 2021, rental providers must ensure a gas safety check of all gas installations is conducted every two years by a licensed gasfitter with a Type A appliance servicing endorsement. Renters in other states should confirm current requirements with their property manager or the relevant state tenancy authority, as obligations differ significantly by jurisdiction and may have changed since this article was published. 

References

Australian Government (energy.gov.au):  Winter energy savings - energy.gov.au

Australian Government (energy.gov.au):  Heating and cooling - filter and servicing guidance - energy.gov.au

Australian Government (YourHome):  Heating and cooling - thermostat efficiency guidance - yourhome.gov.au

Victorian Building Authority:

This article is general information only and does not take your specific circumstances into account. Costs, eligibility, and connection requirements can differ by state, property type and over time. For appliance selection, servicing and safety advice, speak with a licensed gasfitter and follow the manufacturer instructions.

All information provided in this article was correct at the time of publishing (June 2026)

Want to know more? Give us a call on 1300 001 001 or  click here to learn more about our gas network and connection process, including current eligibility, fees and restrictions in your area.