What Size Ducted Air Conditioner Do I Need

Ducted Aircon Size Calculator

Estimate the right system with our ducted air conditioning size calculator. Find the ideal kW based on your home and cooling requirements.

Use our ducted air conditioning size calculator to estimate the ideal kW system for your home. This tool considers home size, layout and conditions to help determine the right ducted air conditioning unit size, so you can choose a system with confidence.

Ducted System Size Estimator Tool

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About your home

Home conditions

Homes with higher heat load, more glazing and lower insulation levels typically need a larger ducted system for effective cooling.

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How Ducted Air Conditioning Size Is Calculated

Our ducted air conditioning size calculator estimates the ideal kW system based on your home's size, layout and conditions. While this provides a reliable guide, it also helps to understand how ducted air conditioning sizing is calculated and what factors influence the final system selection.

Overview

Ducted air conditioning size is calculated by estimating the total heat load of your home, which is then converted into the required cooling capacity (kW).

As a General Guide

  • Most homes require around 0.08 to 0.12 kW per m²
  • Higher heat load = higher kW required

Key Factors That Affect Ducted Air Conditioning Size

The final system size depends on a combination of factors:

  • Home size (m²): Larger homes require more cooling capacity.
  • Ceiling height: Higher ceilings increase air volume and cooling demand.
  • Sun exposure: Homes with more direct sunlight typically need a larger system.
  • Insulation quality: Poor insulation allows heat in, increasing system size requirements.
  • Windows and glazing: Large windows or glass areas increase heat load.
  • Number of rooms and zones: More rooms or complex zoning can impact system sizing.
  • Usage patterns: Heavier usage or higher comfort expectations may require a larger system.

How the Calculator Works

Our ducted air conditioning kW calculator combines all of these factors to estimate the most suitable system size for your home.

Instead of showing a single number, it provides a recommended range (e.g. 12kW–14kW) to better reflect real-world conditions.

Important to Know

In real installations, additional factors are considered, including:

• Duct layout and airflow design
• Return air positioning
• System availability and brand options
• Installation constraints

This is why the calculator should be used as a guide, with final sizing confirmed by a professional.

Next Steps

Use the calculator above as a starting point, then request a quote to get a tailored recommendation based on your home and layout.

To learn more, explore our guides below covering ducted air conditioning sizing, costs and other key considerations.

Ducted System Guides & Insights

Choosing the right ducted air conditioning system isn’t just about picking a size — it’s about getting the balance right for your home, layout and lifestyle. From system sizing and zoning through to costs and long-term performance, these guides will help you make a confident, informed decision before you move forward.

Ducted Air Conditioning Cost

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Split System vs Ducted Air Conditioning

Split vs Ducted Air Conditioning

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How Often To Service Air Conditioner

How Often to Service a Ducted System?

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Not Sure If Your Ducted Aircon Size Calculator Result Is 100% Accurate?

A ducted air conditioning size calculator is a great starting point, but it can’t account for every detail that affects real-world performance.

Our experienced aircon specialists assess factors like ceiling height, window exposure, insulation quality, room usage and zoning layout — all of which can significantly impact the final ducted air conditioning unit size.

This ensures the system is not just “close”, but properly matched to your home for consistent comfort, efficiency and long-term reliability.

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Speak with our team or request a free quote to get started.

0448 752 327

Find the Right Size & Get a Free Quote

Our local aircon specialists will help confirm the correct ducted system size for your home and provide a detailed, obligation-free quote based on your specific requirements.

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