If you can smell gas near your gas heater, this is not something to think about later. It is not something to open a window and hope goes away. It is not something to investigate by sniffing around the appliance.
A gas smell from a heater is a potential safety emergency. Natural gas and LPG are flammable. In an enclosed space, a gas leak can reach explosive concentration. A single spark from a light switch, a mobile phone or a doorbell can ignite it.
This article explains the causes of a gas smell from a heater and, most importantly, exactly what to do right now if you are smelling gas.
What to Do Right Now If You Smell Gas
If you are reading this because you can currently smell gas in your home, stop reading and follow these steps.
Do not touch any switches
Do not turn any light switches, power points or appliances on or off. Do not use your mobile phone inside the property.
Turn off your gas at the meter
Find your gas meter: usually at the front of the property or on the side of the house. Turn the valve 90 degrees until it is perpendicular to the pipe. This shuts off the gas supply.
Open all doors and windows
Ventilate the property to disperse any accumulated gas.
Evacuate if the smell is strong
If the smell is strong, leave immediately. Do not stop to collect belongings.
Call us from outside on 0468 279 956
We respond to gas emergencies 24 hours a day, 7 days a week. Do not re-enter the property until a licensed gas fitter has inspected and cleared it.
Common Causes of a Gas Smell from a Gas Heater
Once the immediate safety situation is managed, here is what typically causes a gas smell from a heater.
A gas leak at a flexible hose connection
The flexible gas hose connecting your heater to the gas supply is one of the most common sources of domestic gas leaks. These hoses have a manufacturer-recommended replacement interval of 10 years. A hose that is older than this, or one that has been kinked, physically disturbed, exposed to heat or cleaning products, or has deteriorated with age, can develop a slow leak at the connection fittings or along the hose body itself.
This is particularly common in Melbourne homes where the flexible hose was installed when the heater was first fitted and has never been replaced. If your heater is more than 10 years old and you cannot recall the flexible hose ever being replaced, it is overdue.
A faulty or deteriorated gas valve seal
The gas valve inside the heater controls the flow of gas to the burner. The valve body and its internal seals can deteriorate with age. A leaking gas valve seal can allow small quantities of gas to escape from the valve body itself rather than through the burner as intended.
This type of leak is often intermittent: detectable when the heater has been running for a while and components are warm, less obvious when the heater is cold.
A gas connection fitting leak
The threaded or compression fitting connecting the flexible hose to the gas outlet on the wall, and the fitting connecting the hose to the appliance, can develop micro-leaks over time. These are often the result of thermal cycling: the connection expanding and contracting with temperature changes over many years of use. They are typically too small to detect by smell and are only reliably identified through a professional gas pressure test.
A brief gas accumulation during ignition
When a gas heater attempts to ignite and fails, the gas valve opens briefly, gas flows to the burner, the ignition fails and the gas valve closes, a small quantity of gas can linger near the appliance before dispersing. This can produce a brief, faint gas odour during a failed ignition attempt.
This is not a leak in the traditional sense, but if you notice a gas smell during or immediately after a failed ignition, it is a sign the heater has a fault and requires professional attention.
Incomplete combustion
When a gas heater's burner is dirty or the air-to-gas mixture is incorrect, incomplete combustion can occur. The byproducts of incomplete combustion include carbon monoxide and various other compounds that can produce an odour sometimes confused with raw gas. Yellow or orange flames instead of blue are the visual indicator of incomplete combustion.
This is both a safety concern in its own right (incomplete combustion produces carbon monoxide) and a sign that the heater requires a professional service.
What Gas Actually Smells Like
Natural gas itself has no odour. Gas companies add a chemical odorant called ethyl mercaptan to natural gas specifically so that leaks can be detected. This odorant has a distinctive smell commonly described as:
- Rotten eggs
- Sulphur
- Skunk-like
LPG has a similar odorant added. The smell is slightly different: often described as stronger and more pungent than natural gas.
If you detect this odour near your heater, near your gas meter or anywhere in your home, treat it as a gas leak immediately.
What You Should Never Do
When you smell gas near a heater, never do any of the following regardless of how mild the smell seems.
Never try to find the leak yourself
Do not apply soap to fittings and look for bubbles. Do not use a lighter to test for gas. Do not sniff closely at connections. Turn the gas off and call a licensed gas fitter with professional detection equipment.
Never reset the heater when you can smell gas
If the heater has a failed ignition and you can smell gas, do not attempt to relight or reset. The smell indicates gas has accumulated. Clear the area first.
Never assume a mild smell is nothing to worry about
A mild gas smell is a warning. It does not become a problem only when the smell is strong. A slow leak can gradually increase in concentration in a closed room without the occupants noticing the change.
Never go back to sleep if you smell gas overnight
A gas smell that wakes you from sleep is a serious warning sign. Evacuate and call us immediately.
After the Immediate Situation Is Managed
Once we attend your property and resolve the gas leak emergency, we will:
- Carry out a full gas pressure test to confirm no residual leaks remain
- Inspect all gas connections, fittings and flexible hoses across the property
- Replace the flexible gas hose if it has reached or exceeded its service life
- Carry out a carbon monoxide test on all gas appliances
- Provide a written report documenting everything found and everything repaired
We do not leave a property after a gas leak call until the post-repair pressure test confirms zero leaks and the CO test confirms all appliances are operating safely.
Preventing Gas Smells from Your Heater
The most effective prevention is regular professional servicing. Our annual gas heater service includes a full gas pressure test and a check of all connections and flexible hoses. We identify deteriorating hoses and micro-leaks before they become detectable by smell.
We also recommend replacing flexible gas hoses every 10 years as a precautionary measure, regardless of apparent condition. The cost of a hose replacement is minimal compared to the cost and risk of a gas leak.
