Strange Smells from Your Heating System - Causes and Solutions

As Canberra homes rely more on heating in the cooler months like July, strange odours can become more common and harder to ignore. Whether it’s something burning, musty or sharp like gas, no smell from your heater should be dismissed.

Some smells can be harmless and go away on their own, but others should get checked quickly. A simple issue like dust build-up might sort itself out, but something more serious like a gas leak or mould in the system can put your health at risk. Knowing the difference helps you act fast when it matters.

Common Causes Of Strange Smells

Every type of smell comes with its own problem, and understanding where these odours come from is the first step towards fixing them. Here are the most common smells you might notice and what they usually mean:

1. Burning Dust Smell

This is one of the most common smells when a heater is switched on after sitting unused. Canberra winters aren’t the longest, so it’s normal for a heater to sit idle for much of the year. Dust collects inside the unit and once it's turned back on, that dust burns off. The smell should go away fairly quickly.

2. Musty or Damp Odours

A musty smell can point to mould or mildew growing somewhere in the heating system, most often in the ducts or vents. This happens when there’s excess moisture or poor airflow. In areas like Canberra where winters tend to be cold and dry, condensation inside old or poorly sealed ducting can still trigger mould. This type of smell usually lingers and returns quickly after the unit turns off, which makes it harder to ignore.

3. Rotten Egg or Sulphur Smell

This one’s serious. That strong, rotten egg smell can mean there’s a gas leak. Gas suppliers add this smell to help people detect leaks quickly, as the gas itself has no odour. If you come across this smell, turn off your heating straight away and leave the area. Contact a professional immediately. Never try to investigate this on your own.

4. Electrical or Burning Plastic Scent

If something smells like wiring or plastic is melting, it could mean a part inside the heater is overheating or short-circuiting. This might happen due to worn wires or a motor problem. These types of smells tend to be sharp and unpleasant. It's a warning sign that your system may not be working safely.

Understanding what these smells mean is one thing, but knowing how they could affect your home and health is even more important.

Potential Health Risks You Shouldn’t Ignore
Strange smells from your heating system aren’t always just a minor nuisance. Sometimes they can create real risks for the people in your home, so it’s important to deal with them before small issues turn into bigger ones.

Mould hiding in the ducts can release spores into the air that might cause mild to severe respiratory issues. For someone with asthma or allergies, this can be even more irritating. Children, pets, or seniors could feel the effects more strongly. If you or someone in the house gets a sore throat, itchy eyes, or a cough that seems to come and go, it might be a sign your air isn't as clean as it should be.

Rotten egg odours can suggest a gas leak, which could lead to dangerous situations like fire or even carbon monoxide exposure. You won't always detect carbon monoxide by smell, so it’s worth treating any strong or strange gas-like smell as a warning and taking action as soon as possible.

When components overheat or wiring burns inside your heater, it might also pose fire risks. This can be harder to pick up on if the unit is inside a wall or roof cavity, which makes regular servicing even more important.

Getting ahead of these problems helps you avoid health risks and keeps your home safe. The sooner strange smells are looked into, the better off you and your family are for both comfort and safety.

Solutions To Address The Smells
Once you’ve identified a strange smell from your heating system, the next step is working out what to do about it. While it might be tempting to poke around and try to solve the problem yourself, the smartest move is to act fast and get help where needed. Some odours signal issues that need attention from experienced professionals, especially if there’s a safety risk involved.

Here’s how to go about tackling the problem:

- Stop and assess. If the smell is strong or unpleasant, switch off your heater. This is especially important if it smells like gas or smoke. Avoid turning it back on until it’s been checked properly.

- Don’t mask the smell. Sprays or air fresheners won’t fix the root issue. It only hides it for a short while, and the real problem continues to grow behind the scenes.

- Call in a professional. Odd odours that don’t go away, or ones linked to gas, electrical faults, or mould, should be checked by a qualified technician. They can inspect the inside of the unit and the ductwork to find what’s going on.

- Regular servicing. Having your heating system serviced once a year helps with performance as well as smell prevention. Technicians can clean out dust, check for leaks, and keep things safe.

- Replace old filters. Dirty or clogged air filters make it harder for your heater to work properly and can cause smells to hang around longer. A technician can inspect and replace old filters during a scheduled check-up.

Avoid putting off the call when something smells strange. Canberra winters might not be as long as other regions, but when the heating is on, it needs to be clean, safe, and working as it should.

When Professional Heating Services Are A Must
Sometimes smells go away quickly, like when you first turn on your heater and it's just a bit of dust burning off. But certain situations are a clear sign you need qualified help. If any of the signs below show up in your home, don’t wait.

- The smell is sharp, chemical-like, or smells like burning wiring or plastic

- Odours come back even after cleaning vents or replacing filters

- You notice symptoms like dizziness, sore eyes, or headaches when the heater is running

- The smell is stronger when you’re near vents or ductwork

- You have an older heating system that hasn’t been checked in over a year

It’s also smart to get help if you’ve made changes to your home layout or insulation. Small things like blocked wall space or poor airflow can affect how your system performs, which might also make smells worse or more frequent.

One Canberra family we helped had a heater that made the lounge room smell like damp towels every time it ran. Turns out, a leak in the ducting was collecting moisture and growing mould. The smell had become so normal they barely noticed until guests did. Once inspected and repaired, the air smelled clean again within a day.

Calling in heating professionals isn’t just about fixing breakdowns. It’s about peace of mind, especially when comfort and safety are both at stake.

Time to Breathe Easy Again
Smells coming from your heater are usually trying to tell you something. Whether it's a simple dust burn-off or a deeper issue needing expert repair, listening to those signs can save you trouble down the line. Canberra’s winters are cold enough without having to worry about strange odours wafting through your house every evening.

Taking early action can prevent health problems, avoid major repairs, and give you a more reliable heating system through the coldest months. Instead of pushing the issue aside, it’s better to get it looked at right away by someone who knows what they’re doing. Keeping your home warm should never come at the cost of safety or air quality. A properly serviced heater will run better, smell cleaner, and help keep everyone in the house feeling comfortable.

Stay warm and worry-free this winter with the help of AGA Air Conditioning. If you're dealing with strange smells or other issues that make your home less comfortable, don't let small problems grow. Explore our expert heating services to keep your system running smoothly. Our experienced team in Canberra is here to help your heating stay safe, efficient, and reliable all season long.