BG electrical & Air Con - Logo (3)

Call: 3279 1835 or 0434 288 108

a man holding a tablet in front of a furnace

A Quick Guide to Furnace Replacement (+ Signs You Need to Do It)

So your rickety old furnace is not turning on again. Perhaps a professional repair service could get it working again. But then it gets you thinking.

Is it time for a furnace replacement?

Let us not forget that the furnace is one of the most important contraptions in your home and also one that consumes the maximum energy. Replacing it with a more efficient model can be a great way to reduce your energy expenses.

If you are not sure about when and how to replace a furnace, you are in the right spot. Here we’ll answer some of the most common questions about a home furnace replacement.

How Long Does a Furnace Last?

a set of white pipes with red valves for central heating

When maintained well, a furnace can last between 15 to 20 years. Higher-end varieties have better build quality and tend to last longer. Now, even a 20-year-old furnace can be repaired to stretch its life.

“Can” doesn’t always mean it should, though.

Once a furnace is worn out, It loses efficiency and heating ability. Besides, frequent repair costs of an out-of-warranty furnace can add up quickly. So, replacing it can be a more practical (and actually cheaper) option.

Keep in mind that furnace life expectancy can depend on multiple factors. 

  • The longevity comes down if it isn’t sized appropriately for your home
  • Poor installation can impact system efficiency and lifespan
  • Setting the thermostat too high or too low can bring down the furnace’s lifespan
  • Lack of maintenance will reduce a furnace’s lifespan.

When Should You Replace Your Furnace: 3 Tell-Tale Signs

News flash: in older furnaces, the efficiency can drop between 56% to 70%. Replacing it with a high-efficiency heating system will bounce efficiency to more than 90%. (100% being the point of ideal conditions, which in real life never happens.) Not only will it save energy costs, but your home’s carbon dioxide emissions will come down as well.

If you pay attention, the furnace will give you signs that it is nearing the end of its running period. Increased frequency of service calls and high repair bills are two pointers that are easily noticed. Beyond that, here are some common signs to look out for.

1. Noise

Thumping or grinding noises in a furnace can indicate issues with the blower motor. If there is a constant clicking sound while running, the problem can be with the compressor. Sometimes popping or rumbling sounds can be heard from the ignition chamber. They can indicate issues with the chamber or the burners.

Any unusual sounds in a furnace should not be taken lightly. Some of these sounds can indicate potentially dangerous internal issues and should be checked by a technician without delay.

2. Poor air quality

The truth is that oil and gas furnaces generate residual gases and harmful pollutants. If your home feels stuffy and there is a rise in allergy symptoms, the venting system may not be working efficiently. Sometimes, a simple thing like cleaning filters will help. But in some cases, there may be strange smells like that of burning dust or plastic. This may indicate gas leaks from the furnace.

Older furnaces lose the ability to manage indoor humidity levels and toxic combustion products can stick to humid air more easily.

Plus, carbon monoxide can leak through cracks in the heat exchanger of an older system. Make no mistake about it, carbon monoxide poisoning can be lethal.

3. Rise in operation frequency

An ageing furnace will lose its ability to generate heat. To compensate, the thermostat will increase the frequency of operation. This, in turn, leads to a vicious cycle. Higher operating times will generate higher stress on the mechanical components and reduce performance further. 

As a result, the system will fail to generate sufficient heat for warming the space. At this stage, you will find inconsistent temperatures across the rooms. Ultimately, the furnace components will start breaking down.

What’s the Cost of Furnace Replacement?

a technician testing things during furnace replacement

The cost of a gas furnace replacement varies depending on the furnace quality and fuel type. For an electric furnace, the cost of replacement can be around $4,000 including installation. The price can be around $6,000 for gas furnaces. Finally, solid fuel furnaces are the costliest option.

Beyond the size, the price will depend on the furnace efficiency, and also on the brand. For example, a furnace with 90% efficiency can cost $1,000 more than a unit with 80% efficiency. Likewise, a two-stage or a variable-speed furnace delivers better efficiency than a single-stage furnace and will cost more.

Then again, if you are installing the furnace only, the cost will be lower. However, if the old ductwork needs to be replaced as well, there will be additional material and labour costs.

Usually, the actual process of installing a new furnace takes anywhere between 4-8 hours. Electrical, ductwork, or gas line modifications will take additional time.

At first glance, the furnace replacement costs seem high. But, you will save money on the energy bills from a high-efficiency model. Plus, you will get better comfort during winters, and much improved indoor air quality.

Can You Replace a Gas Furnace With an Electric One?

Shifting to an electric furnace from using a limited natural resource like gas is a great idea and is very much possible. Modern electric furnaces provide energy efficiency and if you are using solar power, it is a much better choice environmentally. 

In reality, many Australian states, as well as homeowners, are planning to shift to electricity from gas. Besides, the Home Energy Support Program provides rebates to eligible homeowners for installing energy-efficient products.

That said, make sure to check the costs to find out if such a switch makes sense for you. Besides, electric furnaces may not be the ideal heating solution for all homes.

Now, you can’t simply plug a new electrical furnace into an electrical outlet. Firstly, check the building codes in your area and look for regulations you need to follow. Once you get the green light, get help from a licensed electrician to set up a dedicated circuit for the furnace. 

The wiring of some older houses may not be capable of handling an electrical furnace. Depending on the wattage of the new system, the existing circuit may need modifications. (If all of that sounds like too much and your home isn’t very big, you may want to consider smaller and affordable solutions like gas space heaters.)

At the same time, the existing gas lines need to be disconnected and any unnecessary ducting has to be removed. Next, get help from a professional installer for installing the system.

Can a Heat Pump Replace a Gas Furnace?

The answer is yes! However, the conversion process will be expensive and you will need professional installation. On the plus side, heat pumps have multiple advantages. Take a look.

  • Heat pumps are more efficient than combustion heating. So, you will be able to save more on energy expenses.
  • The other advantage is the dual functionality of heat pumps. They can heat and cool your home all year round. Much like a reverse cycle aircon!
  • Heat pumps require less maintenance the gas furnaces. They also emit less greenhouse gases than furnaces.

That said, the air delivered by a furnace is usually warmer than a heat pump. If the winters are super chilly in your area, a gas furnace can make the indoors feel warmer. As always, it is best to make a cost comparison to find out if shifting to a heat pump makes sense for your home.


Why replace a furnace?

Just like all other devices, a furnace loses efficiency as it ages. As the heating ability drops, the furnace will not be an economical option for your home anymore.

How often does a furnace need to be replaced?

The average lifespan of a furnace is between 15 to 20 years. If you invest in a high-quality product and maintain it in the right way, it can perform for 20 years. 

How can I make my furnace run longer?

Here are 5 simple ways to make a furnace last longer.

  • Change or clean the filters as per the manufacturer’s guidelines.
  • Ensure yearly maintenance
  • Keep the air ducts clean and free from leaks
  • Insulate your home to prevent heat leakage and control indoor humidity levels
  • Install a programmable thermostat so that the furnace runs only when needed

Is replacing a furnace difficult?

While it is not difficult, replacing the furnace is not a DIY activity either. You will need professional help to ensure a proper and safe installation.

Call Now Button