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If you’re comparing 7kW vs 5kW split system installation cost, the honest answer is that the gap is smaller than most people expect, usually $300 to $700, but the decision between the two matters more than the price difference suggests. Get the sizing wrong and you’ll either pay for cooling capacity you don’t need, or end up with a unit that runs flat out on the worst days of the year and still can’t keep up. Here’s what each capacity actually costs installed, and how to work out which one your room needs.

Installed Cost: 5kW vs 7kW

A 5.0kW split system typically costs $1,800 to $2,800 fully installed, back-to-back, on a standard brick veneer wall with a short pipe run. A 7.0kW unit runs $2,200 to $3,500 installed under the same conditions. The unit itself only accounts for 50 to 60% of that total, the rest is labour, copper pipe, drain line, mounting, electrical work, and the compliance certificate.

Stepping up from 5kW to 7kW mostly adds cost to the unit, not the labour, typically $400 to $700 more for the equipment itself, since the install process (mounting, piping, commissioning) is largely the same job. Brand tier moves the price far more than the kW jump does: a 5kW Fujitsu or Panasonic can land $1,000 or more below a Daikin or Mitsubishi Electric at the same capacity.

Melbourne metro labour rates sit at the higher end nationally, and Geelong and the Surf Coast generally track close behind. Anything quoted well under $1,800 for a 5kW or $2,200 for a 7kW installed is worth a second look, it’s either missing line items you’ll be charged for on install day, or the installer isn’t covering the job under a current refrigerant handling licence.

Which Size Do You Actually Need?

This is the decision that matters more than the price gap. As a rough guide for a well-insulated room with standard 2.4m ceilings:

  • 5.0kW suits roughly 30 to 40m², a large bedroom, home office, or a modest open-plan kitchen-dining area.
  • 7.0kW suits roughly 40 to 55m², a larger open-plan living zone, a room with a cathedral ceiling, or a west-facing space with a lot of afternoon sun.

If your room sits right on the boundary between those two ranges, size up. A 5kW unit working at its limit on a 40°C day will run constantly, use more power per hour of comfort delivered, and wear out faster than a 7kW unit doing the same job comfortably.

Victoria adds a wrinkle Brisbane guides don’t cover: our climate needs genuine heating capacity too, not just summer cooling. Older weatherboard homes around Torquay, Anglesea, and the Bellarine, common in this region and often with less wall and ceiling insulation than newer builds, lose heat faster in winter, which pushes the sizing call toward the larger unit even in a room that would otherwise sit comfortably in the 5kW range. If your home is exposed to coastal wind, that’s another reason to round up rather than down.

What Changes the Price Beyond the Unit

Whichever size you land on, a handful of factors move the final invoice more than the kW rating does:

Pipe Run and Wall Type

Standard quotes include up to 3 metres of insulated copper pipe. Every extra metre typically adds $40 to $80, and runs past about 7 metres usually need extra refrigerant on commissioning as a separate line item. Double brick or rendered walls add $80 to $250 over standard brick veneer for the penetration.

Condenser Placement

Ground-mounted on a slab is usually included or a small add-on. A wall bracket adds $150 to $300, and anything requiring roof mounting or scaffolding can add $400 to $1,000.

Electrical Work

A 7kW unit is more likely to need a new dedicated circuit and RCBO than a 5kW unit on an older switchboard, typically adding $300 to $600. In Victoria, any electrical work on the install must be certified with a Certificate of Electrical Safety (CES), issued by a licensed electrician, this is separate from the refrigerant handling licence and both need to show up on your paperwork.

Licensing You Should Check For

Anyone handling refrigerant on a split system installation, connecting, charging, decommissioning an old unit, needs a current ARCtick refrigerant handling licence, and the business needs a Refrigerant Trading Authorisation. A legitimate quote will show this licence number. If it’s missing, ask before you book. Installers offering prices well below the ranges above are the ones most likely cutting corners here, and if something goes wrong later, a refrigerant leak, a failed compressor, water damage from a bad drain line, a home insurer can decline the claim if the work wasn’t performed under a valid licence.

Running Cost Difference

The running cost gap between 5kW and 7kW is smaller than the upfront cost gap, since both are modern inverter systems that scale their output to the room’s actual demand rather than running at full capacity constantly. A 5kW unit typically costs $0.15 to $0.30 per hour to run; a 7kW unit sits close behind at $0.20 to $0.35 per hour under equivalent conditions. Correct sizing matters more for running cost than the kW number alone, an undersized unit working overtime on a hot day will often cost more to run than a correctly sized larger unit doing the same job at a comfortable load.

Get the Right Size Quoted Properly

The cheapest quote isn’t always the better deal, and the bigger unit isn’t always the safer bet either, it comes down to your room, your walls, and how exposed your home is to Victorian weather. If you’re deciding between a 5kW and 7kW split system for a home in Geelong, Torquay, or anywhere along the Bellarine, we at Newflo Plumbing are happy to take a look at the space and give you a straight, itemised quote for the size that actually fits. Get in touch for a free onsite assessment.