Split System vs Ducted: What Melbourne Homes Actually Need Electrically

Most homeowners comparing split system and ducted air conditioning focus on comfort, cost, and aesthetics — which is fair, but it skips a genuinely important factor: what each option actually requires from your home's electrical system. Getting this wrong after the units are already ordered is an expensive mistake. Here's what actually matters electrically before you decide.

Split Systems: Smaller Load, More Flexibility

A single split system unit generally draws less power than a ducted system and can often be added to an existing switchboard without a major upgrade, provided there's spare circuit capacity. This makes split systems a more flexible option for homes with an older or nearly-full switchboard, or for homeowners wanting to add cooling to just one or two rooms without a large electrical project. The trade-off is that if you're planning multiple split systems across a home over time, the cumulative electrical load needs to be assessed properly rather than adding units one at a time without checking total capacity.

Ducted Systems: Bigger Commitment, Bigger Load

Ducted air conditioning conditions an entire home from a single, more powerful unit, which draws significantly more power than an individual split system. This almost always requires a dedicated circuit, and depending on the unit's size and your home's existing supply, may require a switchboard upgrade or even three-phase power if it wasn't already available. This needs to be assessed and quoted before you commit to a ducted system, not discovered after installation day.

What to Check Before Choosing Either Option

• Current switchboard capacity: Does your existing switchboard have spare circuit space, or is it already near capacity with ceramic fuses and no room to add safety switches for a new circuit?
• Single-phase vs three-phase supply: Larger ducted systems, and sometimes multiple split systems, may require three-phase power. Confirming what your home currently has avoids a surprise mid-project.
• Cable run distance: Where the outdoor unit sits relative to your switchboard affects both cost and feasibility, particularly for ducted systems where the unit is often positioned away from the house.
• Future plans: If you're renovating or planning other electrical upgrades (EV charger, battery storage), it's worth assessing your total future electrical load together rather than one appliance at a time.

Why This Should Be Assessed Before You Buy the Unit

Air conditioning suppliers and installers are focused on the unit itself — the electrical assessment is a separate, genuinely important step that's easy to skip when a quote looks straightforward. We regularly get called in after a unit has already been purchased, only to find the existing switchboard can't safely support it without an upgrade that wasn't budgeted for. Getting an electrical assessment before finalising your air conditioning choice avoids this entirely.

Frequently Asked Questions

Do I need a switchboard upgrade for a split system?

Not always. If your switchboard has spare capacity and modern circuit breakers, a single split system can often be added without an upgrade. This should be confirmed by an electrician first.

Does ducted air conditioning always need three-phase power?

Not always, but larger ducted systems often do. This depends on the specific unit's power draw and should be confirmed against your home's existing supply before purchasing.

When should I get an electrical assessment done?

Before finalising your air conditioning purchase, not after. This avoids discovering a switchboard upgrade is needed once the unit has already been ordered.

Can I add multiple split systems to my home over time?

Yes, but the cumulative electrical load should be assessed as a whole rather than adding units individually without checking total switchboard capacity.