How to Choose the Right HVAC Split System for Your Next Project
Whether you're fitting out a residential build, upgrading a commercial space, or managing a renovation, choosing the right HVAC split system can make or break the project. The challenge? With so many options — split, ducted, or multi-split — knowing which one fits your client’s needs (and your installation setup) can be tricky.
In this guide, we’ll walk you through how to size, select, and specify the right split system for your job — and what to watch out for before you order.
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Split System vs Ducted vs VRV / Multi-Split — What’s the Difference?
Before choosing, it’s important to understand how each system works:
- Split Systems – These are the most common for single rooms or small areas. You have one indoor and one outdoor unit. Quick to install, affordable, and ideal for homes, offices, or small shops.
- Ducted Systems – Designed for whole-home or large commercial cooling/heating. Air is distributed via ceiling or floor ducts for a clean look and even temperature control.
- VRV / Multi-Split Systems – Perfect for projects needing multiple indoor units connected to one outdoor unit (e.g. apartments, offices, hotels). These systems are efficient and flexible but require careful sizing and planning.
Trade tip: When quoting a project, confirm whether the client wants individual room control (split/multi) or whole-building comfort (ducted/VRV). It saves time and headaches later.
Key Specs That Matter: kW, SEER, and Speed Type
kW Rating / Capacity
Choose a system that matches the room size. Undersizing will overwork the unit, oversizing wastes energy and reduces comfort.
- Small bedroom / office: 2.5–3.5kW
- Living area: 5–7kW
- Open plan / commercial space: 7–10kW+
Use a heat load calculator or consult the product spec sheets to get it right.
SEER / Energy Efficiency
A system’s Seasonal Energy Efficiency Ratio (SEER) shows how well it performs across seasons. The higher the SEER, the lower the running costs — and happier clients.
Many models like Daikin and Fujitsu use inverter technology, improving energy efficiency by automatically adjusting compressor speed instead of cycling on and off like fixed-speed units.
Inverter vs Fixed-Speed
- Inverter: Quieter, more efficient, longer-lasting — the go-to choice for modern installs.
- Fixed-speed: Budget-friendly, but less efficient and can be noisy under load.
What to Watch Out For Before You Order
- Refrigerant Type: Look for systems using R32 refrigerant — it’s more efficient and has a lower environmental impact than R410A.
- Noise Levels: Check the indoor and outdoor unit dB ratings — especially for apartments or night installations. Quiet operation keeps both clients and neighbours happy.
- Warranty and Brand Support: Stick with reliable brands that back up their products with strong after-sales support. Fujitsu and Daikin are trusted choices for Aussie tradies because parts and servicing are easy to access locally.
Trade Tips for Sizing and Installation
- Pre-size before you quote. Use product spec sheets and site measurements — don’t rely on guesswork.
- Avoid oversizing. Bigger isn’t always better; an oversized unit cycles off too quickly and wears out faster.
- Plan your pipe runs early. Keep your lines short and clean for efficiency and fewer call-backs.
- Check electrical and mounting clearances. Always follow manufacturer installation guides to ensure compliance with AS/NZS standards.
Product Picks from James Group
Here are a few popular options from our range that tradies trust:
- Fujitsu Lifestyle Range Wall-Mounted Split Systems – Great efficiency, simple install, and reliable performance.
- Daikin CORA Series Wall-Mounted Split Systems – A trusted choice for Aussie homes, featuring inverter technology, R32 refrigerant, and whisper-quiet operation. Available in sizes from 2.0kW to 9.0kW, perfect for anything from bedrooms to open-plan areas.
Browse Split Systems at James Group
Wrapping Up
Choosing the right HVAC split system doesn’t have to be complicated — it just takes the right info, a good sizing plan, and reliable gear. Whether you’re fitting out a single room or a multi-zone setup, getting it right means fewer call-backs, happier clients, and better project margins.
Trade Support from James Group
Need help finding the perfect system for your next job?
Our team can help you compare models, check specs, and secure trade-exclusive pricing on trusted brands.
Contact us today or register for a trade account — and get the right system, right away.