What to Check Before Installing a New Air Conditioner in Your Adelaide Home

Most Adelaide homeowners start shopping for a new air conditioner by looking at brands and price. That's understandable, but it skips the four decisions that actually determine whether the finished install performs well, runs safely, and doesn't need revisiting in twelve months: correct sizing, electrical capacity, physical placement, and the right system type for your home's layout. Get any one of these wrong and you can end up with a unit that's technically installed but never quite does the job.

We're Voltas Electrical & Airconditioning (licences BLD 274739 · PGE 265145 · AU 61210), and because we handle both the electrical and air conditioning side of an installation, we see the jobs where these checks were skipped — usually by a previous installer who only ever quoted the unit itself. This checklist runs through what we actually check on-site before quoting any air conditioning installation across Adelaide metro, so you know what to ask for even if you're getting quotes from more than one installer.

1. Get the Sizing Right — Avoid Over- or Undersizing the Unit

Air conditioner capacity is rated in kilowatts (kW) of cooling output, and it needs to match the space it's cooling — not be rounded up "to be safe" or down to save money. Both mistakes cause real problems. An undersized unit runs at full output constantly and still struggles to reach temperature on a hot Adelaide day, which shortens its working life and pushes running costs up rather than down. An oversized unit cools the air too quickly without properly removing humidity from it, which means the room reaches temperature but still feels clammy, and the compressor short-cycles — switching on and off more often than a correctly sized unit would, which is harder on the system long-term.

As a rough starting point, Adelaide homes typically need somewhere around 2.0–3.5kW for a small bedroom, 3.5–5.0kW for a standard bedroom or study, 5.0–7.0kW for a single living room, and 7.1kW or more for an open-plan living/dining/kitchen area — but ceiling height, insulation age, window orientation, and how open-plan the space is can shift that up or down a full size bracket. We cover the full breakdown, including what specifically pushes sizing up or down, in our guide to what size split system you actually need. The reference ranges are a useful starting point, but the only reliable way to land on the right capacity is a licensed technician's on-site heat-load assessment — not an online calculator working from two dimensions.

2. Check the Electrical Circuit Can Handle the New Unit

This is the check that gets skipped most often, because it's invisible until something trips or overheats. Air conditioners — especially anything above a small single-room split system — draw a meaningful electrical load, and in South Australia that load has to be wired in line with AS/NZS 3000, the wiring rules the state's electrical safety regulator enforces. In practice, that generally means a fixed appliance like a split system needs its own dedicated circuit sized to the unit's actual current draw, rather than sharing a circuit with general power points or lighting.

Before any new air conditioner goes in, a licensed electrician should check three things: whether your switchboard has a spare circuit available, whether the switchboard itself has the capacity and safety switch protection to take the new load safely, and whether the existing wiring from the switchboard to the installation point is adequate or needs upgrading. This matters more in older Adelaide homes — a switchboard installed decades ago, before ducted or multiple split systems became common, can be at or near capacity before the new unit is even connected. If yours needs attention, our guide on when to upgrade your switchboard covers the warning signs worth checking first.

Because we hold both electrical (BLD 274739 · PGE 265145) and air conditioning licences, we check the circuit and switchboard as a standard part of quoting any installation — not as an add-on discovered halfway through the job. A qualified electrician must carry out this work regardless of which installer you use; it's not something to leave to a general handyman or DIY.

3. Plan Indoor and Outdoor Unit Placement — Noise, Airflow and Aesthetics

Where the indoor head and outdoor compressor actually sit affects how well the system performs and how much you notice it day to day, and it's easy to get wrong when placement is chosen for convenience rather than checked properly.

4. Split System, Multi-Split, or Ducted — What Actually Suits Your Home's Layout

Sizing and placement assume you've already picked the right type of system, and that decision comes down to how many rooms you actually want conditioned and what your roof space allows — not which option a salesperson leads with.

A single split system suits one room — a living area, main bedroom, or a small unit or townhouse — and is the fastest and cheapest option to install. A multi-split system runs two to four indoor head units off a single outdoor compressor, which is a genuinely useful middle ground when you need several rooms conditioned but ducting isn't practical or affordable — an older home with a low-pitch roof is a common case where multi-split ends up the more realistic option rather than the cheaper one. Ducted air conditioning suits homes where most rooms are used regularly and there's enough roof cavity space to run ductwork — it disappears from view entirely and is controlled from one central panel or app, at a meaningfully higher installed cost than either split option.

We cover this decision in full, including real Adelaide installation cost ranges, in our comparison of split system vs ducted air conditioning, and our complete guide to ducted air conditioning if that's the direction your home is leaning. All of our systems come from genuine, trusted manufacturers — see our full air conditioning brands range — across every price point and system type.

5. Questions to Ask an Installer Before You Commit

A genuinely thorough installer should be comfortable answering all of the following before you sign off on a quote. If any of these get brushed off, that's worth treating as a warning sign.

• "How did you calculate the capacity for this room?" — a real answer references ceiling height, insulation, sun exposure and room shape, not just square metres.
• "Have you checked my switchboard and circuit capacity?" — this should happen before quoting, not discovered as an unexpected extra cost on installation day.
• "Where exactly will the outdoor unit sit, and why there?" — a considered answer covers airflow, noise, and sun exposure, not just "wherever's closest to the wall."
• "What's included in the quote — is it fixed or an estimate?" — ask specifically whether electrical work, old-unit removal, and refrigerant recovery are included or billed separately.
• "Are you licensed for both the electrical connection and the refrigerant handling?" — both are legally required in Australia; a technician without a current refrigerant handling licence under Commonwealth ozone protection law cannot legally connect a new system, and the electrical connection needs a licensed electrician.
• "What warranty applies, and who backs the workmanship?" — the manufacturer covers the unit; a reputable installer backs their own install with a separate workmanship guarantee.

Every installation we quote across Adelaide — from established suburbs like Burnside to newer developments in Golden Grove — comes with a fixed, itemised quote covering sizing, electrical checks, and placement upfront, backed by our 100% satisfaction guarantee and workmanship guarantee on every install.

Sources referenced include AS/NZS 3000 wiring rules and energymining.sa.gov.au for South Australian electrical safety requirements, and the Australian Refrigeration Council's refrigerant handling licence requirements under Commonwealth ozone protection law, cross-checked against our own Adelaide installation experience.