What is an Open Flued Gas Heater?

If you’ve ever come across the term “open flued gas heater” and wondered what it means, you’re not alone.

These types of gas heaters have been used in Australian homes for years, but they’re now attracting more attention – mainly due to safety concerns.

An open flued gas heater draws air from the room to fuel the flame and expels combustion gases through a flue or vent, usually connected to the roof or wall. While effective for heating, they can pose serious risks if not properly installed or maintained.

In this blog, we’ll explain exactly what an open flued gas heater is, how it works, the benefits and risks, and what the current safety regulations are. Whether you already have one or are considering your options, this guide will help you make informed decisions.

Why are Open Flued Heaters a Potential Risk?

An open flued gas heater is a type of space heater that burns gas to generate warmth, using the air inside the room to fuel the flame.

The term “open flued” means the heater is open to the air in the room and relies on a flue (or vent) to carry away the combustion gases, like carbon monoxide (CO), to the outside.

These heaters were once a popular choice for many Australian homes due to their affordability and effective heat output. However, they can be risky if the room isn’t properly ventilated or if the flue becomes blocked.

Without enough fresh air coming in, harmful gases can leak back into the room, creating a serious health hazard. That’s why understanding how these systems work – and the conditions they need to operate safely – is so important for anyone using or considering one.

How Open Flued Gas Heaters Work

Open flued gas heaters may look simple, but there’s a specific process behind how they operate. Here’s a breakdown of how they work:

• Air intake from the room: These heaters draw in air from inside the room to support the combustion process. This means they rely on the room’s natural airflow to function safely.
• Gas combustion: Once the gas ignites, it produces a flame that heats up a metal surface or heat exchanger. This generates warm air that’s circulated into the room.
• Exhaust through a flue: The combustion gases – like carbon monoxide – are vented outside through a flue, typically through the wall or roof.
• No sealed chamber: Unlike room-sealed heaters, there’s no barrier between the flame and the room, making ventilation absolutely critical.
• Safety depends on airflow: If there’s not enough fresh air, or if the flue is blocked, dangerous gases can leak back into your living space.

Benefits of Open Flued Gas Heaters

Despite their safety concerns, open flued gas heaters do offer some practical benefits – especially in certain settings. Here are a few reasons they’ve been popular in Australian homes:

• Lower upfront cost: These heaters are generally more affordable to purchase compared to room-sealed or ducted systems.
• Simple installation: With fewer components and no need for a sealed air supply, they’re easier and quicker to install in older homes.
• Effective heating: Open flued models can warm up a space quickly and maintain a comfortable temperature, making them suitable for cold climates.
• Compact design: Many models are small and wall-mounted, ideal for homes with limited space.
• Widespread availability: Replacement parts and servicing knowledge are still readily available for many open flued models.

While the benefits are clear, it’s important to weigh them against modern safety expectations and the suitability for your specific home setup.

Safety Concerns and Risks

While open flued gas heaters can be effective, they also come with significant safety concerns. Here’s what you need to know:

• Carbon monoxide risk: If the flue is blocked or ventilation is poor, carbon monoxide – a colourless, odourless and potentially deadly gas – can leak into your home.
• Gas leak: Like any gas appliance, an open flued heater can also leak gas into the home, which is easier to detect than CO (due to the odour) but still potentially dangerous.
• Back-drafting: Strong winds or negative air pressure can reverse the airflow in the flue, pushing exhaust gases back into the room.
• Poor ventilation hazards: These heaters rely on air from the room, so if your home is tightly sealed (common in modern builds), dangerous gases may not be vented properly.
• Outdated models: Older open flued heaters may lack modern safety features, increasing the risk of malfunction or gas leaks.
• Incorrect installation or servicing: DIY fixes or unqualified technicians can compromise the heater’s safety.

Due to these risks, regular servicing and carbon monoxide testing are essential if you have an open flued gas heater.

Legal Regulations and Compliance in Australia

In Australia, open flued gas heaters are subject to strict safety regulations – and for good reason.

Over the years, there have been serious incidents involving carbon monoxide poisoning, prompting regulatory bodies to tighten the rules. In some states, the sale and installation of certain models of open flued gas heaters have been banned altogether, especially those that don’t meet modern safety standards.

For example, Victoria has introduced mandatory carbon monoxide testing for all gas appliances during routine servicing, and older open flued heaters may need to be disconnected if they pose a risk. Installers must follow the relevant Australian Standards, including AS/NZS 5601 for gas installations, and ensure adequate ventilation.

If you’re using one of these heaters, it’s important to have it serviced by a licensed gasfitter at least once a year. Staying compliant isn’t just about following the rules – it’s about keeping your household safe.

Alternatives to Open Flued Heaters

If you’re thinking about upgrading from an open flued gas heater, there are several safer and more efficient alternatives available. Here are some great options to consider:

• Room-sealed gas heaters: These gas-powered units draw air from outside and expel exhaust gases externally, reducing the risk of carbon monoxide entering your home.
• Flued gas heaters (modern models): Newer flued gas systems are designed with improved safety features and are compliant with current regulations.
• Reverse cycle air conditioners: Reverse cycle systems provide both heating and cooling, are energy efficient, and don’t produce combustion gases.
• Electric panel heaters: Great for smaller spaces, they’re easy to install and safe for bedrooms or enclosed areas.
• Hydronic heating systems: A hydronic heating system is quiet, efficient, and ideal for whole-home heating, though they do come at a higher cost.

Each alternative has its own pros and cons, so it’s worth speaking to a licensed technician about what’s best for your home.

Should You Replace Your Open Flued Heater?

If you have an open flued gas heater at home, you might be wondering whether it’s time for an upgrade – and in many cases, the answer is yes. While these heaters were once a go-to option for affordable warmth, they come with serious safety concerns.

The main issue is the risk of carbon monoxide leaking back into your living space, especially in tightly sealed or poorly ventilated homes. If your heater is older, hasn’t been regularly serviced, or is located in a bedroom or small room, it could be putting your family at risk.

Replacing it with a room-sealed or flued gas heater that meets modern safety standards is a smart move. Not only will you enjoy better energy efficiency, but you’ll also have peace of mind knowing your home is safer.

Always speak to a licensed gas fitter about your options and any government rebates that may help with replacement costs.

Have Your Heater Checked Regularly

Open flued gas heaters were once a popular choice for many Australian homes, offering simple and effective heating.

But as our understanding of gas safety has improved, so too have the standards around these appliances. While they may still work well in some settings, the potential risks – especially carbon monoxide leaks – mean they’re no longer the go-to option.

If you currently have one, it’s important to stay on top of maintenance, ensure proper ventilation, and have it checked regularly by a licensed gas fitter. And if your heater is old or in a high-risk area, it might be time to consider a safer alternative.

With plenty of modern, efficient options available, upgrading can offer peace of mind and better performance. Always prioritise your family’s safety when it comes to home heating.

Please note: This information is provided for advice purposes only. Regulations differ from state to state, so please consult your local authorities or an industry professional before proceeding with any work. See Cyber Air Conditioning’s Terms & Conditions here.