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Types of Gas Furnaces: Choose the Right Heating System for Your Home

When choosing a furnace, are you just going for the cheapest? Affordability matters, but choosing the right gas furnace type is more important. Spending a bit more upfront could save you money on utilities later.

In this guide, we’ll walk you through the different gas‑furnace options and show you how to pick the best one for your needs before calling a professional for a  new gas installation. Let’s get into it.

What Should You Consider Before Choosing a Gas Furnace?

Before you compare types of furnace, it’s good to know what matters when it comes to heating your home:

1. Climate Zone

Melbourne winters range from 0 to 15°C, making adjustable heating important. Sydney’s milder winter, between 8 and 18°C. This often reduces the need for a powerful system.

Coastal areas face salt air corrosion, which can shorten furnace life. And in Brisbane, basic heating usually meets infrequent needs. In short, start with your local climate and environment.

2. Home Size and Layout

The size of your home affects how much heating you need. A small, one-story house is easier to heat, but a big five-bedroom or multi-story place is tougher.

Larger homes often have cold spots. Those rooms that stay cold. So, you might need more advanced systems that gently move the air to keep every part of your house cosy.

3. Existing Infrastructure

Ductwork, gas supply, and venting influence your choice of gas furnace type.

If your home already has ducts in the roof or under the floor, replacing the unit is simple for a tradie. On the flip side, installing new ductwork can cost thousands and may affect which furnace type works best for you.

4. Upfront Budget

Now we’re talking about the upfront cost. Gas furnace prices vary. A single-stage costs between 3,000 and 4,000 to 6,000. That initial difference can seem steep, right?

But, what seems cheaper at first might end up costing you more later if you don’t pick the right gas furnace type. When choosing a furnace, you’re not just making a one-time purchase, you’re investing for 15 to 20 years.

5. Energy Efficiency

Upfront costs are important, but efficiency matters. How well your furnace turns gas into heat decides whether you’re cozy or frustrated this winter.

A 3-star single-stage unit costs less upfront but uses more gas over time than a 6-star modulating system. Upgrading can reduce gas use by 20% to 30% annually, saving money over 15 years.

6. Comfort Priorities

It’s not just about temperature that makes you comfortable. You also need to think about the noise level. Those are things to think about when choosing a gas furnace type.

Basic single-stage furnaces are like a light switch. They’re either all the way on or off. And if you work from home or have kids sleeping, the noise from a single-speed blower running full blast can be distracting.

7. Control and Compatibility

Another thing to think about when choosing a gas furnace is the zoning feature. It lets you heat only the rooms you are using. If you set it up right, it can save you around 30% on your winter energy bills.

Modern systems offer Wi-Fi, so you can turn on the heat remotely before leaving the office. And smart thermostats can learn your schedule and adjust the temperature automatically while you sleep.

8. Brand and Warranty

For some Australian homeowners, brand reputation is a key filter. That’s why they often stick with trusted brands like Brivis, Braemar, Bonaire, or Rinnai.

But, reputation alone doesn’t guarantee a good furnace. You need to check out the warranty, especially for the heat exchanger, since it’s the priciest part to replace.

And make sure your installer is a licensed gas fitter. That way, you’ll avoid problems later, like a furnace that smells like gas

6 Types of Gas Furnace You Should Know

To choose the right type of gas furnace, you need to look at three main parts: the burner, the blower, and the gas type.

1. Single-Stage Gas Furnace

  • Type: Burner Type

Single-stage gas furnaces work like a light switch. When your thermostat calls for heat, the furnace turns on at full power until the room reaches the set temperature.

The gas valve opens fully, quickly heating the heat exchanger. The blower runs at full speed, pushing air through the ducts. When the room reaches the set temperature, the furnace turns off.

Single-stage gas furnace with vertical design and dual access panels for residential heating

Image: Durastar.com

Pros:

  • Lowest upfront purchase cost, typically 3,000 to 6,000 installed in Australian homes
  • Simple mechanical design with fewer components to fail
  • Easy for any licensed gas fitter to service and repair
  • Fast initial heating when you first switch it on

Cons:

  • Highest ongoing running costs due to inefficient cycling
  • Noticeable temperature fluctuations as the system switches on and off
  • Loudest operation with frequent start-up noise

2. Two-Stage Gas Furnace

  • Type: Burner Type

Two-stage furnaces have two gas settings: about 65% for low and 100% for high. It mostly runs on low and switches to high only when very cold.

Low-stage provides gentler, more even heat without the hot blast of single-stage systems. It runs longer at lower power, distributing warmth more evenly.

Two-stage gas furnace with dual vent ports and front access panels for efficient home heating

Image: geappliancesairandwater.com

Pros:

  • Significantly better energy efficiency, saving 300 to 600 annually on power bills
  • More consistent room temperatures with smaller fluctuations
  • Quieter operation since low-stage runs produce less noise
  • Longer equipment lifespan from less stressful operation

Cons:

  • Higher upfront cost at 5,000 to 9,500 installed
  • Slightly more complex to service than single-stage units, like when your gas fireplace smells like gas
  • Not all brands available in every Australian region

3. Modulating Gas Furnace

  • Type: Burner Type

Modulating furnaces make heating way more precise. Instead of just two settings, they can run anywhere from 40% to 100% capacity, adjusting in 1% steps.

Your furnace watches your home’s temperature and changes how much it works to keep it just right. On warm mornings, it might run at 45%, but on very cold nights, it goes all the way to 100% without any problem.

Modulating gas furnace with dual-panel access and variable heat output for precise comfort

Image: Arcoaire.com

Pros:

  • Highest energy efficiency, saving 600 to 1,200 annually compared to single-stage
  • Near-perfect temperature consistency with minimal fluctuations
  • Quietest operation of all furnace types
  • Optimal for large or multi-storey homes with complex heating needs

Cons:

  • Highest upfront investment at 7,000 to 12,000 installed
  • Quite complex, requiring a professional for installation and gas leak detection service for maintenance.
  • Limited availability in some Australian regions
  • May be overkill for small homes or mild climates

4. Single-Speed Blower Gas Furnace

  • Type: Blower Speed

A single-speed blower is the simplest fan you’ll find in cheap gas furnaces. It works on a basic idea: when the burner turns on, the blower runs at full speed, and it stays that way until the heating cycle is over.

When your thermostat calls for heat and the burner starts, the blower kicks to full speed instantly, pushing warm air through your ducts with a loud “whoosh.” When the burner turns off, the blower stops immediately.

Pros:

  • The most affordable you can buy, usually 200–400 more than basic single-stage furnace units
  • Simple mechanical design that’s easy to understand and fix
  • Easy to replace if the motor fails after 15+ years
  • Very reliable with few electronic controls that can break

Cons:

  • High electricity use for the blower motor increases power bills, alongside gas costs
  • Can be very noisy in open-plan areas, disrupting TV viewing or sleep
  • Wastes energy by running at full speed even in mild weather, when less power is enough

5. Multi-Speed Blower Gas Furnace

  • Type: Blower Speed

A multi-speed blower furnace has a few fixed fan speeds. Unlike variable-speed systems, it doesn’t change speeds automatically; your installer sets the speed once during installation.

If it’s set to Medium, it stays there; if High, it stays high. The good thing is, they can adjust it just right for your home before finishing, instead of a single speed blower that might not fit.

Single-stage gas furnace with vertical design and dual access panels for residential heating

Image: amazon.com

Pros:

  • Better airflow control
  • Quieter than single-speed fans once set up properly
  • Cheaper than variable-speed options but still offers better performance than single-speed fans
  • Easier to install in large, complicated, or hard-to-heat homes

Cons:

  • Less energy-efficient than modern variable-speed DC motors
  • Changes in your home’s heating needs may make the fixed speed unsuitable
  • Less effective during shoulder seasons (autumn/spring) when heating needs vary daily

6. Variable-Speed Blower Gas Furnace

  • Type: Blower Speed

This type of gas furnace has a variable-speed blower with a high-efficiency DC motor, called an ECM, that can smoothly and constantly change the fan speed.

When you turn on the heat, the variable-speed furnace slowly ramps up the fan. This avoids the sudden “cold draft” you get with single- or multi-speed blowers before the heat exchanger warms up.

Variable-speed blower gas furnace with dual-panel access and precise airflow control

Image: comfortmaker.com

Pros:

  • Uses up to 50% less electricity
  • The quietest fan technology, ideal for open spaces and noise-sensitive homes
  • Stops the “cold draft” problem

Cons:

  • Its advanced electronics can lead to costly repairs if the motor fails
  • Requires a compatible thermostat and control system
  • This technology is rare in Australia, available only in Braemar’s premium 7-star range

Which Gas Furnace Type Should You Pick?

Here’s how to match these gas furnace types to your situation:

If you are on a tight budget

  • Choose a Single-stage + Single-speed heater.
  • If you can spend $500 more, a multi-speed fan makes it quieter.

If you want the best value

  • Get a Two-stage burner + Multi-speed blower.
  • It’s a big upgrade from an old 3-star heater and makes your home more comfortable.

If you live in a multi-story or forever home

  • Buy a Modulating burner + Variable-speed blower.
  • Being able to control the heat helps with zoning in multi-story homes, and it saves energy over time, making the extra cost worth it.

FAQ About Types of Gas Furnace

Here are some of the common gas furnace questions most homeowners ask:

1. What is the most common type of gas furnace in Australia?

The most common modern setup is a two-stage burner with a multi-speed blower. It gives you a good balance of a 4 or 5-star energy rating without the high cost of a premium modulating gas furnace.

2. What type of furnace is usually used in Australian homes?

Most Australian homes use natural gas heaters. Older houses usually have single-stage burners, but newer ones and renovations are moving toward two-stage and modulating gas furnaces to save energy.

3. Is a gas furnace considered an HVAC system?

“HVAC” means Heating, Ventilation, and Air Conditioning. A gas furnace, or ducted heater, is the “H” part. You can often add refrigerated cooling to make it a full HVAC system.

Conclusion

Whether you want a budget-friendly single-stage basic or an ultra-efficient modulating premium, the best gas furnace for you depends on your location, budget and how long you’ll stay in your home.

Remember, a gas furnace is a 15–20 year investment, so your choice now will affect your comfort for years.

And if you’re unsure and need a professional assessment, call us at Melbourne Gas Plumber. We’ll help you explore your options and choose the right gas furnace.

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