Carbon monoxide safety and gas heater servicing: what Victorian homes should know

What carbon monoxide is, and why a gas heater can produce it

Carbon monoxide, or CO, is a gas produced whenever a fuel like natural gas is burned. In a heater that is installed correctly, burning cleanly, and venting properly, the small amount of CO produced during normal combustion is carried safely outside through the flue. The danger starts when that combustion is not clean, or when the CO it produces cannot escape the way it is meant to. Energy Safe Victoria is direct about the risk: carbon monoxide is a gas you cannot see or smell, and when it spills from a gas heater into a living space, it can make a household seriously ill or worse. [1][2]

There are a small number of ways this typically goes wrong, and they share a common thread: something is stopping the heater from burning fuel completely or venting the by-products properly. An unserviced burner can develop a dirty or maladjusted flame that burns incompletely, producing more CO than a clean flame would. A blocked or damaged flue, whether from debris, corrosion, birds' nests, or a knocked or disconnected flue pipe, can stop combustion gases escaping the way they are designed to. A cracked heat exchanger, the part of a ducted gas heater that separates the combustion chamber from the air being blown through the house, can let combustion by-products leak directly into the airstream being pushed into living rooms and bedrooms. [1][2]

None of these faults are visible from the outside in the way a leaking tap or a cracked pipe would be. A heater with a developing flue blockage or a hairline crack in its heat exchanger can keep producing heat normally, keep the house warm, and give no obvious sign anything is wrong, right up until the fault becomes severe enough to spill a dangerous amount of CO into the home. That is precisely why this is a servicing and inspection issue rather than something a household can reliably judge by how the heater looks or sounds. [1][2]

It is also worth being clear that this applies to any gas heater, not just older units. Energy Safe Victoria's guidance covers central ducted heaters, gas space heaters, wall furnaces, and decorative gas log fires alike, old or new. Newer appliances are generally built with better safety shutdown features, but none of that removes the need for regular servicing, because the risk comes from how the appliance is installed, maintained, and vented over time, not just from its age or its original build quality. [1]

The Energy Safe Victoria guidance: service at least every two years

Energy Safe Victoria's standing recommendation is straightforward: have every gas heater in the home serviced at least once every two years by a licensed or registered gasfitter. That applies regardless of how the heater has been performing, because the faults that lead to CO spillage are not always the kind a household would notice from ordinary daily use. Its 'Be Sure' campaign exists specifically to push that message, because CO incidents keep occurring in homes where the heater seemed to be working fine right up until it was not. [2][1]

Open-flued heaters deserve a specific mention here. These are heaters that draw combustion air from inside the room and vent exhaust gases through a flue, rather than drawing air from outside and sealing the combustion process off from the living space the way a room-sealed appliance does. Energy Safe Victoria has taken a firm position on this technology, restricting the sale of older open-flued space heaters that lack safety shutdown features, including second-hand units, and treating open-flued heaters generally as harder to reconcile safely with modern, well-sealed, energy-efficient homes. An exhaust fan, a rangehood, or even a clothes dryer running elsewhere in a well-sealed house can create enough negative pressure to pull combustion gases back into the room instead of up the flue, which is a genuinely different risk profile to a room-sealed system. [1]

A renovation is a specific trigger point worth flagging on its own. Sealing up a home for energy efficiency, adding insulation, replacing draughty windows, or closing off old vents, all genuinely good things for a comfortable, efficient house, can change how an existing gas heater behaves if it relies on air movement through the room to vent properly. Energy Safe Victoria's guidance specifically calls out post-renovation servicing for this reason. A heater that vented safely in a draughty house is not guaranteed to vent safely in the same house after it has been sealed and insulated. [1]

The two-year interval is a minimum, not a target to stretch toward. Older heaters, heavily used heaters, heaters that have never been serviced since installation, and open-flued heaters in a recently sealed or renovated home are all reasonable candidates for more frequent checks, and a licensed gasfitter is the right person to advise on that rather than a general rule of thumb. [2][1]

Warning signs a homeowner can actually notice

While a developing CO problem is not something a household can reliably diagnose on its own, there are warning signs worth knowing, and the Better Health Channel lists them clearly. Watch the flame itself: a healthy gas flame burns a steady blue, and a flame that has turned yellow or sooty, other than on a heater specifically designed to look like a decorative log fire, is a signal to stop using the appliance and have it checked. Soot marks around the heater casing, heat discolouration or scorching on nearby walls, an unusually hot exterior casing, or a pilot light that will not stay lit are all documented signs of a heater that is not burning or venting the way it should. [3][1]

Unusual sounds matter too. Popping, banging, or a noticeably different noise from the heater compared to how it has always sounded can indicate a burner or ignition problem worth having looked at, even if the heater still seems to be producing heat normally. Energy Safe Victoria's own guidance is blunt about this category of change: if the flame changes colour, or the heater starts behaving differently to how it always has, that is reason enough for an inspection, not something to wait out until the next scheduled service. [1]

The symptoms of CO exposure itself are the other half of this picture, and they are easy to mistake for something else entirely. The Better Health Channel lists tiredness, headaches, dizziness, nausea, shortness of breath, weakness, and confusion as the common signs, and low-level, longer-term exposure can look more like general malaise, poor concentration, or irritability rather than an obvious poisoning. Energy Safe Victoria's own consumer messaging adds a genuinely useful pattern to watch for: several people, or pets, in the same household feeling unwell at similar times, or a household member who feels noticeably better away from home and worse again after returning, both of which point toward the building rather than an unrelated illness. [3][2]

None of these signs are a substitute for regular servicing, and it is worth being honest about that rather than implying a household can simply watch for symptoms instead of booking a service. By the time CO symptoms are noticeable, exposure has often already been happening for some time. The warning signs are useful for catching a developing problem between services or acting quickly if something changes suddenly, not for replacing the two-yearly service as the primary safeguard. [3][2][1]

What a proper gas heater service actually includes

It is worth being precise about this rather than treating carbon monoxide checking as a separate add-on service, because it is not sold that way by the regulator or by a competent gasfitter, and Hyde does not frame it that way either. Energy Safe Victoria's guidance describes CO testing as something a qualified gasfitter does as part of inspecting the heater and its installation, using a CO analyser to test for spillage, alongside checking the appliance itself, its installation, and its flue. A competent gas heater service simply includes this testing as a normal, expected part of the visit, in the same way a technician checks gas pressure or ignition, not as a premium extra a household has to specifically ask for. [1]

A proper service therefore covers more ground than a quick clean and a flick of the pilot light. It should include inspecting the burner and flame for even, correct combustion, checking the heat exchanger for cracks or corrosion, checking the flue and its connections for blockages, damage, or incorrect installation, verifying safety shutdown and lockout functions are working, and testing for CO spillage at the appliance and around the casing while it is running. If a fault is found, Energy Safe Victoria's guidance is direct: a gasfitter is required to make the installation safe, which may mean adjusting or repairing the appliance, or in some cases red-tagging it and turning it off until it can be properly repaired. [1]

The gasfitter doing this work matters as much as the checklist itself. Only a licensed or registered gasfitter, with current registration through Victoria's Building and Plumbing Commission, is legally permitted to service, inspect, or repair gas heating appliances and their flues in Victoria. Consumer Affairs Victoria's guidance for rental gas checks specifically calls out the need for a gasfitter endorsed in servicing Type A gas appliances, the category most household gas heaters fall into, and that same standard is the sensible benchmark for any household booking a service, rental or not. [4][5]

Hyde's gas ducted heating service and its broader service and repairs work both include this kind of proper inspection as standard, not as something bolted on afterward. A service that skips flue inspection, heat exchanger checks, or CO testing is not a complete gas heater service, whoever is doing it, and it is worth a household asking directly what a quoted service actually includes before booking it. [1][5]

CO alarms: a genuine backup, not a substitute for servicing

A carbon monoxide alarm is a sensible, inexpensive addition to a home with gas heating, and the Better Health Channel recommends one that meets a recognised safety standard, such as the European EN50291 or American UL2034 standards, as a backup precaution. It is worth being clear about the word backup. A CO alarm detects a dangerous concentration of gas that is already accumulating in the room; it does not prevent a heater from producing CO in the first place, and it does nothing to catch a developing fault before it becomes a spillage event. [3]

Placement matters for an alarm to actually do its job. The Better Health Channel's guidance is to install alarms in rooms containing gas appliances and to make sure they can be heard from sleeping areas, since CO exposure during sleep is one of the more dangerous scenarios precisely because the symptoms, drowsiness and confusion, are easy to sleep through rather than notice and react to. [3]

The honest way to frame a CO alarm to a household is as one layer in a system that starts with proper servicing, not as the primary safeguard. A well-serviced heater with correctly checked combustion and an intact flue should not be putting meaningful CO into the home in the first place. The alarm exists to catch the rare case where something goes wrong between services, or where an installation or appliance fault develops faster than the service interval anticipated, not to make servicing optional. [1][3]

Rental property obligations in Victoria

Victoria's rental minimum standards include a specific gas safety obligation, and it is worth Peninsula landlords and property managers knowing the detail rather than assuming a general maintenance clause covers it. Under the Residential Tenancies Regulations, a rental provider entering into a residential rental agreement must ensure a gas safety check is carried out on the gas installations and fittings at the property at least every two years, by a gasfitter licensed or registered and endorsed for servicing the relevant class of gas appliance. [4]

If a gas safety check has not been done within the last two years by the time a renter moves in or a tenancy is renewed, Consumer Affairs Victoria's guidance is that the rental provider must arrange one as soon as possible rather than waiting for the next natural service window. Records of the check need to be kept, including the gasfitter's name and licence number, the date of the check, the results, and any repairs required, and a renter can request a copy of that record, which the rental provider must be able to produce within a set timeframe. [4]

This obligation exists for the same underlying reason as the general two-yearly servicing guidance from Energy Safe Victoria, but it carries legal weight for rental providers specifically rather than being general good-practice advice. A tenant living with a poorly maintained gas heater has no practical way to arrange their own service or inspect the flue and heat exchanger themselves, which is exactly why the obligation sits with the rental provider rather than being left to the household using the appliance. [4][1]

For landlords and property managers across the Peninsula, the practical takeaway is to treat the two-yearly gas safety check as a standing calendar item tied to the property rather than to a specific tenancy, and to keep the paperwork somewhere it can actually be found on request. A gas heater service booked through Hyde's service and repairs team can be scheduled to satisfy this obligation directly, with the CO testing, flue inspection, and record-keeping that a compliant check requires handled as part of the one visit. [4][5]

When to shut a heater off and call someone

Some situations call for switching the heater off immediately and arranging a service before using it again, rather than waiting to see if the issue resolves itself. A flame that has turned yellow or sooty, soot marks or heat discolouration around the unit, a pilot light that will not stay lit, unusual banging or popping noises, or a household member developing headaches, dizziness, or nausea that eases when they leave the house and returns when they come back are all reasons to stop using the heater and call a licensed gasfitter. [3][1]

If a CO alarm actually sounds, the response is more urgent again: get everyone, including pets, out into fresh air immediately, do not go back inside to investigate the appliance, and call for emergency help if anyone is showing symptoms of CO exposure. This is not a situation to troubleshoot from inside the house, and it is not a situation where turning the heater off and reopening a window is an adequate response on its own before the appliance has been properly inspected. [3]

Outside of an active alarm or acute symptoms, the safe next step for a suspected fault is the same short list every time: turn the heater off at the appliance, do not attempt to inspect or repair the burner, flue, or heat exchanger directly, and book a licensed gasfitter to inspect it properly, mentioning the specific symptom or sign that triggered the call so the technician knows where to look first. That is squarely within the same territory Hyde treats seriously across every gas appliance it services: the checks a homeowner can safely do stop well short of the gas and combustion components, and that line exists for real safety reasons rather than as caution for its own sake. [1][6]

The Hyde takeaway on carbon monoxide safety

Carbon monoxide risk from a gas heater is well understood, well documented, and genuinely preventable. It comes from incomplete combustion or a blocked or damaged vent path, most often in a heater that has gone too long without a proper service, and Energy Safe Victoria's core message, service every gas heater at least every two years through a licensed gasfitter, remains the single most effective thing a Victorian household can do about it. [1][2]

CO testing is not a separate product to add to a booking. It is simply what a competent gas heater service already includes, alongside checking the burner, the heat exchanger, and the flue, and it should be treated that way by any household or landlord comparing quotes. A CO alarm is a sensible, genuinely useful backup layer, and Victoria's rental rules make the two-yearly check a legal obligation for rental providers rather than optional good practice, but neither replaces the inspection itself. [1][3][4]

For Peninsula homeowners and landlords, the practical next step is straightforward: know when the heater was last serviced, watch for the warning signs the Better Health Channel and Energy Safe Victoria both document, install a CO alarm as a backup, and book a proper service through Hyde's service and repairs or gas ducted heating team if it has been close to, or past, two years. That is a small, routine piece of home maintenance standing between a household and a risk that is otherwise very hard to detect on its own. [1][5]