---
title: Do you need to replace the ductwork when upgrading your Ducted Heater?
description: Upgrading to refrigerated ducted air conditioning? Learn why replacing old ductwork can improve efficiency, comfort and system performance.
image: https://gthvace.com.au/hubfs/This%20is%20an%20image%20of%20old%20ductwork%2c%20insulation%20and%20ventilation%20components%20removed%20during%20a%20ducted%20gas%20heating%20upgrade%20to%20a%20refrigerated%20ducted%20air%20conditioning%20system%20by%20GT%20HVAC%20%26%20Electrical%20in%20Melb.jpg
---

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# Do you need to replace the ductwork when upgrading your Ducted Heater?

![GT HVAC & Electrical](https://gthvace.com.au/hubfs/Screenshot%202025-04-14%20at%202.51.13%20PM.png) [GT HVAC & Electrical](https://gthvace.com.au/latest-news/author/gt-hvac-electrical)  Sep 10, 2026, 1:00:00 AM

- [Ducted Heating](https://gthvace.com.au/latest-news/tag/ducted-heating),
- [Melbourne](https://gthvace.com.au/latest-news/tag/melbourne)

![This is an image of old ductwork, insulation and ventilation components removed during a ducted gas heating upgrade to a refrigerated ducted air conditioning system by GT HVAC & Electrical in Melb](https://gthvace.com.au/hs-fs/hubfs/This%20is%20an%20image%20of%20old%20ductwork%2c%20insulation%20and%20ventilation%20components%20removed%20during%20a%20ducted%20gas%20heating%20upgrade%20to%20a%20refrigerated%20ducted%20air%20conditioning%20system%20by%20GT%20HVAC%20%26%20Electrical%20in%20Melb.jpg?width=960&height=960&name=This%20is%20an%20image%20of%20old%20ductwork%2c%20insulation%20and%20ventilation%20components%20removed%20during%20a%20ducted%20gas%20heating%20upgrade%20to%20a%20refrigerated%20ducted%20air%20conditioning%20system%20by%20GT%20HVAC%20%26%20Electrical%20in%20Melb.jpg)

 

Upgrading from an ageing ducted gas heater to a modern refrigerated ducted air conditioning system is one of the best investments you can make for year-round comfort. Not only do you gain efficient heating during Melbourne's cold winters, but you'll also enjoy whole-home cooling through the summer months.

One of the most common questions we hear at **GT HVAC & Electrical** is:

**"Do I need to replace my existing ductwork?"**

The short answer is **in many cases, yes.**

While it might seem like a way to save money by reusing the existing ducts, older ductwork is often not suitable for today's refrigerated ducted air conditioning systems. Differences in airflow requirements, ageing insulation and deteriorating materials can significantly affect the performance of your new system.

Let's look at why replacing your ductwork is often the smartest long-term investment.

---

## Why Your Existing Ductwork May Not Be Suitable

Your home's ductwork is responsible for distributing conditioned air throughout every room.

Although it sits hidden in your roof space, it plays a critical role in how efficiently your heating and cooling system performs.

When upgrading from a ducted gas heater, many homeowners assume the existing ductwork can simply be connected to the new unit.

Unfortunately, this isn't always the case.

---

## 1. Refrigerated Air Conditioning Requires Much Higher Airflow

The biggest difference between ducted gas heating and refrigerated air conditioning is the amount of airflow each system requires.

### Ducted Gas Heating

A ducted gas heater is designed to operate with **lower airflow**.

Reducing the airflow allows air to spend longer passing over the heat exchanger, absorbing more heat before being distributed throughout the home.

This design works perfectly for heating.

### Refrigerated Ducted Air Conditioning

A refrigerated system must provide both:

- Heating
- Cooling

Cooling works very differently.

To cool your home effectively, the system must move a **much larger volume of air** throughout the house.

If the ductwork is too small, the airflow becomes restricted, meaning your new system has to work much harder to achieve the desired temperature.

---

## Problems Caused by Undersized Ductwork

Installing a new refrigerated system on undersized ductwork can result in several issues, including:

- Reduced cooling performance
- Poor heating efficiency
- Uneven temperatures between rooms
- Increased energy consumption
- Louder system operation
- Additional wear on the fan motor
- Reduced system lifespan

Instead of enjoying the full benefits of your investment, you may find the system never performs as well as it should.

Replacing the ductwork ensures your new air conditioning system operates exactly as the manufacturer intended.

---

## 2. Old Ductwork Doesn't Last Forever

Another major reason we recommend replacing ductwork is simply its age and condition.

Roof spaces experience extreme temperatures throughout the year.

During summer, temperatures inside a Melbourne roof cavity can become incredibly hot.

Over many years, this heat causes:

- Insulation to deteriorate
- Outer duct lining to become brittle
- Flexible ducting to collapse
- Air leaks to develop
- Connections to loosen

On a recent installation completed by GT HVAC & Electrical, we removed the existing ductwork and discovered it had deteriorated so badly that it literally crumbled apart during removal.

Although it looked acceptable from the ceiling vents, once removed it was obvious it had reached the end of its service life.

---

## What Happens When Ductwork Deteriorates?

Damaged ductwork doesn't just reduce efficiency.

It can have a noticeable impact on your home's comfort.

Common problems include:

### Energy Loss

Air escaping into the roof space means you're paying to heat or cool an area nobody uses.

### Reduced System Efficiency

Your air conditioner has to operate longer to compensate for the lost airflow.

### Higher Power Bills

The harder your system works, the more electricity it consumes.

### Uneven Room Temperatures

Some rooms may receive too much airflow while others remain uncomfortable.

### Increased Wear

Restricted airflow places extra strain on the fan motor and other system components.

---

## New Ductwork Maximises Your Investment

A new refrigerated ducted air conditioning system represents a significant investment.

Replacing old ductwork ensures you receive the maximum return on that investment.

Modern insulated ductwork offers:

- Better airflow
- Improved insulation
- Reduced energy loss
- More even temperatures
- Quieter operation
- Improved efficiency
- Longer system life

It also allows your installer to correctly size every duct to suit the airflow requirements of the new system.

---

## Can Existing Ductwork Ever Be Reused?

In some situations, existing ductwork may still be suitable.

This generally depends on factors such as:

- Age of the ductwork
- Overall condition
- Correct duct sizing
- Insulation quality
- Layout of the home
- Number of outlets
- Type of new air conditioning system

Every home is different.

At GT HVAC & Electrical, we inspect each installation individually before making recommendations.

If your ductwork is in excellent condition and correctly sized, we will always discuss the most practical solution with you.

---

## Upgrading Through the VEU Rebate

Many homeowners upgrading from ducted gas heating are taking advantage of the **Victorian Energy Upgrades (VEU) Program**.

Replacing an older gas heating system with an energy-efficient refrigerated ducted air conditioning system may qualify for significant rebates, helping reduce the overall installation cost.

When assessing your eligibility, GT HVAC & Electrical also evaluates whether your existing ductwork is suitable for the upgrade, ensuring your new system delivers the efficiency and performance expected.

---

## Why Professional Design Matters

Every home has different heating and cooling requirements.

Professional system design considers:

- Home size
- Ceiling height
- Insulation
- Room layout
- Window orientation
- Airflow calculations
- Duct sizing
- Outlet locations

Simply connecting a new unit to old ductwork without these considerations often results in poor performance.

A properly designed duct system ensures every room receives balanced airflow and consistent temperatures.

---

## Why Choose GT HVAC & Electrical?

GT HVAC & Electrical provides professional refrigerated ducted air conditioning installations throughout **Melbourne, Bayswater, Kilsyth, Croydon, Lilydale, Ringwood, Boronia, Wantirna, Vermont, Glen Waverley, Box Hill, the Yarra Valley and surrounding suburbs**.

Our experienced team specialises in:

- Ducted air conditioning upgrades
- Ducted gas heater replacements
- Refrigerated heating and cooling systems
- Daikin installations
- Ductwork replacement
- Air conditioning servicing
- Heating maintenance
- VEU rebate upgrades

Every installation is carefully designed to ensure maximum comfort, efficiency and long-term reliability.

---

## Thinking About Upgrading Your Heating?

If you're planning to replace your ageing ducted gas heater with a refrigerated ducted air conditioning system, don't overlook the importance of your ductwork.

While reusing existing ducts may seem like a cost-saving option, outdated or undersized ductwork can significantly reduce the performance of your new system.

By replacing ageing ductwork during your upgrade, you'll enjoy:

- Better airflow
- Lower running costs
- Improved heating and cooling
- Greater energy efficiency
- More consistent temperatures
- Longer system life

The team at **GT HVAC & Electrical** can assess your existing ductwork and provide honest, expert advice on the best solution for your home.

**Contact us today** to discuss your ducted heating upgrade and discover how a professionally designed refrigerated air conditioning system can keep your home comfortable all year round.

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